Paper Bone graft

Document Sample
Paper Bone graft Powered By Docstoc
					Paper #1

Treatment of Adolescent Idiopathic Scoliosis with Pedicle Screw-Only Constructs: Minimum 3-Year Follow-
up of 103 Consecutive Cases

Ronald A. Lehman, Jr. MD (Washington University Medical School); Lawrence G. Lenke, MD; Kathryn
Keeler, MD; Yongjung J. Kim, MD; Gene Cheh, MD; Jacob Buchowski, MD; Craig A. Kuhns, MD; Brenda Sides,
MA; Keith H. Bridwell, MD

Purpose: To analyze the intermediate-term follow-up of a large,consecutive series of adolescent idiopathic
scoliosis(AIS) patients treated with pedicle screw constructs at one institution by radiographic parameters,
pulmonary function testing(PFT), Scoliosis Research Society(SRS) scores and complications. There have been no
reports of the intermediate-term findings in North America following posterior spinal fusion with the use of pedicle
screw-only constructs in a larege series of AIS patients.

Methods: 103 consecutive AIS patients with a minimum 3-yr-follow-up (mean=4.8;range=3.01-7.30years) were
evaluated. Radiographic measurements(AP,LAT,supine,side-bending films) included preoperative (PreO),
postoperative(PO), 2-year(2Yr) and final follow-up(FFU). Chart review evaluated: PFTs, SRS scores, presence of
thoracoplasty, Lenke classification and complications.

Results: The average age at time of surgery was 15.1+2.2years. The most frequent curve type was Lenke
Type1(40.24%), followed by Lenke Type3(26.83%). The average main thoracic(MT) curve measured 59.2
+12.2SD(PreO), and corrected to 16.8 +9.9SD(PO)(p<0.0001). Thoracic kyphosis(T5-12) decreased from 25.81° to
15.5° at FFU (p=0.05). Nash-Moe grading for apical vertebral rotation (AVR) in the MT curve decreased from
2.04(PreOp) to 1.09 at FFU(p<0.0001), while AVR in the TL/L spine decreased from 1.6(PreOp) to 1.14 at FFU
(p<0.0001). Importantly, the horizontalization of the subjacent lower disc measured (-8.32°)PreO and decreased to (-
0.94°)PO (p<0.001). Finally, the clavicle-angle (α) improved from (-2.20°)PreO to 1.14° at FFU(p<0.0001). PFTs
follow-up averaged 2.44yrs with improvement in FVC of 7.1%(p=0.004) and FEV1 of 8.8%(P<0.0001). SRS scores
averaged 83% at latest follow-up. One case of distal adding-on and 2 deep wound infections required additional
surgery. No neurologic, pseudarthrosis or implant complications developed.

Conclusions:This is the largest(N=103), consecutive series of North American patients with AIS treated with
pedicle screws having a minimum 3-year follow-up. The average curve correction was 68%(MT), 50%(PT), and
66%(TL/L) at FFU. We found excellent coronal/sagittal balance, curve correction and improved AVR at follow-up.
There were no construct-related complications/decompensation, pseudarthrosis or neurologic deficits.
     Paper #2

     Surgical Revision Rate of Hooks vs. Hybrid vs. Screws vs. ASF/PSF for AIS

     Timothy R. Kuklo, MD, JD (Walter Reed Medical Center); Lawrence G. Lenke, MD; Benjamin K. Potter,
     MD; David W. Polly, Jr., MD; Brenda Sides, MA; Keith H. Bridwell, MD

     a - Medtronic Sofamor Danek

     Background: Much debate continues on the safety, efficacy and cost of thoracic pedicle screws in AIS to determine
     the need for repeat surgery; and therefore, the added indirect costs and risks Nonetheless, there are no large series
     which have evaluated the revision rate of various constructs of additional procedures.

     Methods: We retrospectively reviewed the surgical case logs of 1,428 patients with AIS at two institutions from
     1990-2004, and the clinical records and radiographs of revision cases. Patients were classified into one of 4 groups:
     hook constructs, hybrid constructs, all screw constructs, and combined ASF/PSF. Overall, there were 64 (4.5%)
     returns to the OR, or 54 (3.8%) cases after excluding infections without pseudarthrosis.

     Results: Of the 64 revision cases, there were 51 females and 13 males, at an average age at first surgery of 13.9
     years (range, 9-18), and an average age at revision of 14.7 (range, 12-23). For the revision cases, the average Cobb
     was 61.9 (range 44-110 ), and this was not statistically different within the cohorts (p>0.05). In terms of revision
     rate, all hook constructs had a higher revision rate 2 instrumentation failure when compared to screws, while both
     hooks and hybrid constructs had an overall higher surgical revision rate when compared to screw constructs or
     anterior/posterior constructs (all p≤0.05; see table). The pseudarthrosis rate trended toward, but did not meet, (added
     comma) statistical significance between these same groups. (See table)

     Conclusions: All pedicle screw constructs have a lower surgical revision rate when compared to hook and hybrid
     constructs. The hidden costs of these findings should be considered when evaluating instrumentation efficacy.

              N          Dislodged                             Prominent
                                           Pseudarthrosis                     Infection    Crankshaft      Other      Total
             (%)      Instrumentation                           Implant
                                                                                                                       25
 Hooks        389         9 (2.3)**           6/2* (2.1)         3 (0.8)       4 (1.0)        2 (0.5)      1 (0.3)   (6.4)**
                                                                                                                       24
 Hybrid       423          7 (1.7)            10/1* (2.6)         0 (0)        6 (1.4)         0 (0)       1 (0.2)   (5.7)**
 Screws       295           0 (0)               2 (0.7)          2 (0.7)       1 (0.3)         0 (0)       2 (0.7)   7 (2.4)

ASF/PSF     321          1 (0.3)              3 (0.9)            2 (0.6)        2 (0.6)        0 (0)        0 (0)     8 (2.5)
 Total     1428            17                   21                  7             13             2            4      64 (4.5)
*concomitant pseudarthrosis with infection (3 cases); **statistically significant chi-squared analysis vs. screws (p <
0.05).
Paper #3

Re-Operation Following Primary Posterior Multiple Anchor Instrumentation and Arthrodesis for Idiopathic
Scoliosis

Douglas C. Burton, MD (University of Kansas Medical Center); Marc A. Asher, MD; Sue Min Lai, PhD

d – Isola Implants

Purpose: A post-market surveillance study to determine re-operation indications and frequency.

Materials and Methods: From 1989 through 2002, 208 consecutive patients, index patient included, age < 20 years
were operated. Charts and questionnaires were reviewed. One hundred ninety-nine (96%) patients were followed an
average 7 years 2 months (range, 2 years to 16 years 7 months) and 9 (4%) an average 11 months (range, 3 to 22
months).

Results: Nineteen patients (9.1%) had re-operation: Three (1.4%) peri-operative and unrelated to implants: Eight
(3.85%) for pseudarthrosis (3), delayed deep wound infection (2), implant prominence (1), or spondylolisthesis (2; 1
with adjacent de-novo and 1 with peri-adjacent, pre-existing spondylolysis): and Eight (3.85%) for late operative site
pain (LOSP). The principle variable affecting re-operation was the transverse connector utilized. From 1989 to
October 1995 threaded transverse connectors were utilized in 96 of 98 patients. From October 1995 through 2002
closed drop entry transverse connectors, with 3+ times greater gripping strength, were utilized in 107 of 110
patients. None of the constructs with closed drop entry transverse connectors required re-operation because of
LOSP, whereas 8 of the constructs with threaded transverse connectors did, p = 0.0086 (likelihood ratio). Interval to
re-operation for LOSP averaged 5 years 11 months; and for lumbar spondylolisthesis the intervals were 11 years 5
months and 15 years 5 months. Both had three mobile lumbar motion segments following their index surgery.

Conclusions: Provision of a stronger transverse connector significantly decreased frequency of re-operation for late
operative site pain. We believe this added strength decreased fretting corrosion, the probable cause of late operative
site pain. Others have reported that it requires ≥ 10 years for lumbar spine degeneration and instability below
idiopathic scoliosis instrumentation constructs to appear. Long-term follow-up is an indicated part of care.
Paper #4

Maturity Assessment and Curve Progression in Girls with Idiopathic Scoliosis

James O. Sanders MD (Shriners Hospitals for Children); Richard Browne, PhD; Sharon McConnell; Sue
Margraf; Timothy Cooney; David Finegold

a - Scoliosis Research Society Grant

Background: Scoliosis progression during adolescence is closely related to patient maturity. Being
multidimensional, maturity includes various components including chronological age, height and weight changes,
skeletal and sexual maturation. It is not certain which of these dimensions correlates most strongly with scoliosis
behavior. This study’s purpose is to evaluate various maturity measurements relative to scoliosis progression.

Methods: Physically immature girls with idiopathic scoliosis were followed every six months through their growth
period with serial spinal radiographs, hand skeletal ages, Oxford pelvic scores, Risser sign determinations, heights,
weights, sexual staging and serologic studies of IGF-1, IGFBP-3, DHEA-s, estradiol, bone specific alkaline
phosphatase and osteocalcin levels. These measurements were then correlated with the curve acceleration phase
(CAP).

Results: The period and pattern of curve acceleration began during Risser 0 for all patients. Skeletal maturation
using the Tanner-Whiteside III (TWIII) RUS method, particularly of the metacarpals and phalanges, was superior to
all other dimensions of maturity determination. Regression of the scores allows good estimates of maturity during
the period of curve progression (Pearson r=0.93). The initiation of this period occurs simultaneously with digital
changes from TWIII stage F to G or covered to capped. At this stage curves also separate into rapid, moderate, and
low acceleration patterns with specific curve types for the rapid (Lenke 1 and 3) and moderate groups (Lenke 2, 4, 5,
and 6) with distinct prognosis. The low acceleration group is not confined to a specific curve type.

Conclusions: The curve acceleration phase (CAP) separates curves into various types of curve progression with
differing prognosis. The TWIII RUS scores are highly correlated with timing relative to the CAP and provide better
maturity determination and earlier prognosis during adolescence than the other parameters tested. Accurate skeletal
maturity determination should be used as the primary maturity measurement in girls with idiopathic scoliosis.
                                             (Paper #4 attachment)

Stage             Estimated   Corresponding Maturity       Skeletal age attributes of        Metacarpal and
                    CAP       Marker in Girls              the metacarpals and             phalangeal portion of
                                                           phalanges                            RUS score
                                                           (TWIII stages in                   (DSA Scores)
                                                           parenthesis)
Juvenile Slow     Before -6   Tanner 1                     All may be covered (F) but
                                                           capping (G) rare
Pre Adolescent       -6       Tanner Breast 2              All covered and 6-7 capped              375
Slow                                                       (G)
Curve                0        Peak Height Velocity         All but 1 or 2 capped                   400
acceleration                  TRC stage 2
phase begins
Rapid                +6       Tanner Breast 3              A few starting to fuse (H)              420
Adolescent
Acceleration
Early               +12       TRC Closed                   Distal phalanges fused (I) or           440
Adolescent                    Menarche                     fusing
Steady
Progressive
Late Adolescent     +18       Positive Risser sign         Most phalanges are fusing or            500
Steady                                                     fused
Progressive
Early Maturity      +24       Risser 4                     All phalanges fused                     600
                              Distal Radius beginning to
                              fuse
Paper #5

Curve Progression at Least Ten Years after Maturity in Patients with Moderate Adolescent Idiopathic
Scoliosis – A Prospective Comparison of Observation or Brace Treatment

Alf L. Nachemson MD, PhD (Sahlgrenska University Hospital); Aina J. Danielsson, MD; Ralph Hasserius;
Acke Ohlin, MD, PhD

INTRODUCTION: Brace treatment was shown to be superior to electrical muscle stimulation or observation in the
previously performed prospective SRS brace study, including consecutive series of immature patients with AIS of
moderate curve size (Cobb 25-35).

PURPOSE: To perform a long term follow up regarding curve changes of the Swedish patients included in the
original study.

METHODS: Sixty-five patients were treated with observation only as the intention to treat and 41 patients received
Boston brace treatment. The majority of the patients attended a clinical and radiological follow-up, including
(re)measurement of curve sizes (Cobb). Patients having undergone surgery after maturity were identified through
search of the mandatory national database for performed surgeries.

RESULTS: The age at FU for all patients was mean 32 years and follow-up time 16.0 years after completed
treatment/maturity. So far, 79% of the patients have been followed.

The group with observation as the intention to treat had a Cobb value of 30.1° at base-line. Twenty-three (35.4%)
patients had a curve increase ≥ 6° during the original study and were counted as failures. Of those, thirteen (20.0%)
patients underwent brace treatment and six underwent surgery before maturity.

Curve size now was mean 35.9° for observed only patients, 50% had increased ≥ 6°, but only four had a curve size
beyond 45°.

Patients brace treated originally now had a curve size of mean 31.8°, 48% had increased by ≥ 6° and one patient had a
curve size beyond 45°.

No patients had undergone surgery after maturity.

CONCLUSION: Six patients in the observed group and none in the brace group were operated during adolescence
and no one during the mean 16 year follow-up.

Patients observed only have not increased their curves more often than patients initially brace treated. The number of
patients with a curve size beyond 45° does not differ between these groups either.
Paper #6

Scoliosis After Solid Organ Transplantation in Children and Adolescents

Ilkka Heleniu, MD, PhD (Helsinski University Central Hospital); Hannu Jalanko; Ville Remes, MD; Sari
Salminen; Christer Holmberg; Jari Peltonen, MD

a - Foundation for Paediatric Research
a - Paulo Foundation
a - Päivikki and Sakari Sohlberg Foundation

Summary: The occurrence of scoliosis was high after solid organ transplantation in childhood. Heart transplantation
and growth hormone treatment were most significant risk factors.

Introduction: The occurrence of scoliosis in children after solid organ transplantation is not known.

Methods: A total of 196 children (75 females), which is 93% of patients surviving kidney, liver and heart
transplantation (tx) in our country, participated. The subjects were transplanted at the mean age of 6.5 years (range,
0.4 to 18.1 years) and were postoperatively followed for a mean of 9.2 years (range, 2.4 to 20.5 years). Their mean
age at follow-up was 15.7 years, range 3.7 to 30.4 years. All children were screened for rib hump, and those with
clinically significant hump (>6 degrees) underwent radiographs of the spine. The occurrence of scoliosis was
compared to data obtained from a previously published comparison group.

Results: Forty-six (23.5%) children showed a hump of 6 degrees or more in the clinical examination. Forty-three
(21.9%) had a scoliosis greater than 10 degrees, and 21 (10.7%) of them had curves greater than 20 degrees (p45
degrees), and five have been operated. The RR (95%CI) for scoliosis needing treatment (over 25 degrees) was 17.0
(6.75–42.7) as compared with control population. The occurrence of scoliosis was 17.9% of the kidney, 13.6% of
the liver, and 51.7% of the heart transplant patients (p <0.001). After adjusting for age at tx and gender, heart
transplantation (OR [95%CI] 7.27 [2.62–20.2]) and growth hormone treatment (3.98 [1.77–8.94]) were most
significant risk factors for scoliosis. Low bone mineral density, female gender, frequency of rejection episodes, and
methylprednisolone dosing were not associated with increasing risk of scoliosis.

Conclusion: Every fifth chil developed scoliosis after solid organ transplantation. Growing spine needs close
follow-up after solid organ transplantation.


Scoliosis              Kidney tx (n=123)        Liver tx (n=44)        Heart tx (n=29)         Controls (n=855)*
≥10°                   22 (17.9%)               6 (13.6%)              15 (51.7%)              79 (9.2%)†
10°-19°                14 (11.4%)               3 (6.8%)               5 (17.2%)               73 (8.5%)
20°-44°                7 (5.7%)                 0 (0%)                 4 (13.8%)               6 (0.7%)
≥45°                   1 (0.8%)                 3 (6.8%)               6 (20.7%)               0 (0.0%)†
*Control values from the study of Nissinen et al (Acta Pediatr 1993;82:77-82). †χ2-test p<0.001.
Paper #7

Thoracoplasty in Thoracic Adolescent Idiopathic Scoliosis

Se-Il Suk, MD; Jin-Hyok Kim, MD; Sung-Soo Kim, MD (Inje University Sanggye Paik Hospital); Jeong-Joon
Lee, MD; Yong-Taek Han,MD; Beom-Cheol Cho, MD

Purpose: To evaluate the effect and outcome of thoracoplasty in conjunction with pedicle screw instrumentation in
the treatment of thoracic adolescent idiopathic scoliosis (AIS).

Materials and Methods: Eighty-seven patients with thoracic AIS (mean age, 14.4 years) treated by pedicle screw
instrumentation and a minimum follow up 2 years were retrospectively analyzed. Patients were divided into three
groups; N-T group (no thoracoplasty with iliac bone graft, n=37), T-N-DVR [thoracoplasty with no direct vertebral
rotation (DVR), n=20] and T-DVR group (thoracoplasty with DVR, n=30). In the T (T-N-DVR+T-DVR) group, 5 to
7 ribs were resected and used as bone graft. Patients were evaluated for deformity correction, pulmonary function,
size of rib hump, operating time, complications and clinical outcomes (SRS-30).

Results: In the N-T group, the thoracic curve was corrected from 53 to 16 (69% correction), and in the T-N-DVR
group from 55 to 18 (69%) and in the T-DVR group from 54 to 10 (81%). There was no difference in
postoperative spinal balance and pulmonary function among the three groups. Rib hump was corrected from 31mm
to 19mm (35% correction) in N-T group, from 32mm to 13mm (53%) in T-N-DVR and from 32mm to 9mm (69%)
in T-DVR. The T group showed significantly better correction of rib hump and clinical outcome score in the SRS-30
than N-T group. The operating time was 172 minutes in the N-T group, 190 minutes in the T-N-DVR group and 216
minutes in the T-DVR group. There were 8 iliac donor site problems in the N-T group and 3 pleural effusions in the
T group, which had no adverse effect in the final result. All patients accomplished bony union.

Conclusions: Thoracoplasty showed significantly better rib hump correction, satisfactory clinical outcomes without
pulmonary function compromise or iliac bone graft site morbidity in the treatment of thoracic AIS with pedicle
screw instrumentation.
Paper #8

Increased Kyphosis and Pain Following Implant Removal for Idiopathic Scoliosis

Karl E. Rathjen, MD (Texas Scottish Rite Hospital); Megan Wood; Anna McClung; Zachary Vest

Purpose: To determine the clinical and radiographic results in patients with idiopathic scoliosis who had complete
implant removal following posterior spinal fusion.

Methods: 39 of 54 (72%) patients whose implants had been completely removed at least two years previously
completed a recent SRS-22 questionnaire and standing AP and lateral radiographs.

Results: The average time from implant removal was 10 years (Range: 3 to 18)
3 patients had between 11 º to 20 º of coronal plane progression of a fused thoracic curve.
1 patient had 14 º of progression of a proximal junctional kyphosis.
17 patients had between 11 º to 20 º of progression of their thoracic kyphosis and 5 patients had > 20º of progression
of thoracic kyphosis. Patients with a larger Pre-Op T5 to T-12 kyphosis were statistically more likely to progress
after implant removal.(Logistic regression analysis, p=0.013)
Total SRS-22 scores averaged 75.1 for patients with < 20º of progression of thoracic kyphosis and 68.2 for patients
who progressed > 20º (p= 0.034). The average score in the Pain Domain was 18.3 for patients with < 20º of
progression of thoracic kyphosis and 15.0 for patients who progressed > 20º (p= 0.025) (See Table)

Conclusions: Implant removal after posterior spinal fusion for idiopathic scoliosis may not be a benign procedure.
Patients should be appropriately counseled and monitored.

                        Pre-op       Progression.       Progression        Total             Pain Domain
                        T5-12        T2-T12             T5-12              SRS 22            SRS-22
Group I (n=17)          23 º         2.2 º              3.5 º              76                18.4
Group II (n=17)         23 º         11.6 º             11.1 º             74.2              18.4
Group III (n=5)         42 º         12.2 º             22.8 º             68.2              15

Group I = Patients with < 10 º degrees sagittal progression
Group II = patients with 11 º to 20 º of progression in either T2 to T12 or T5 to T12 Group III = Patients with > 20 º
progression in either T2 to T12 or T5 to T12
Paper #9

The Evaluation of Shoulder Balance in Healthy Adolescent Population and its Correlation with Radiological
Measures

Ibrahim Akel, MD; Murat Pekmezci, MD; Muharrem Yazici, MD (Hacettepe University); Mutlu Hayran;
Orhan Derman; Ilkay Erdogan; Ahmet Alanay, MD; Ozgur Kocak

Introduction: In healthy individuals shoulders are accepted as level, but this general acceptance has not been
confirmed before. The aim of this study is to evaluate the shoulder balance in normal population and to determine
the ideal radiological method that reflects clinical shoulder imbalance.

Methods: Adolescents without orthopedic pathology formed the study group. They were asked to fillout a
questionnaire assessing shoulder perception, and had their digital picture taken simultaneously with a P-A chest X-
ray during which they were asked to stand straight and have their arms on sides. The clinical shoulder balance was
evaluated by measuring the digital pictures with special software. The X-rays were used to evaluate the radiological
shoulder balance. The evaluated parameters were T1-Tilt, clavicular angle (CA), coracoid height difference (CHD),
clavicular tilt angle difference (CTAD) and the difference between clavicula-rib cage intersection points (CRID).

Results: The study group was composed of 71 adolescents. All stated that their shoulders were level. The clinical
shoulder balance demonstrated level shoulders in only 11(16%). Radiological examination showed level shoulders
in 9 with CTAD, 8 with CA, 36 with CRID and 6 with CHD. T1 tilt was zero in 23. The average CTAD was
3.9±3.4(0–20), CA was 2.3±1.8(0–11), CHD was 7.3±5,1mm (0-27.5), T1-Tilt was 1.4±1.4(0–6) and CRID
1.7±2.1mm (0-7.6). The evaluation of the pictures revealed an average 7.7±5.9mm (0-27) heigth difference between
shoulders. All radiological parameters but CRID correlated with clinical picture(p <0.01). Clavicular angle(r=0.80)
and coracoid height difference(r=0.77) demonstrated strong, CTAD demonstrated moderate correlation(r=0.59).
Discussion: In contrast to common belief, the shoulders are not level in healthy adolescents. Clavicular angle and
coracoid height difference can be used reliably to evaluate clinical shoulder balance. Although CTAD demonstrated
moderate correlation, it is still a valuable alternative when the shoulders are not completely seen on the X-ray.

Discussion: In contrast to common belief, the shoulders are not level in healthy adolescents. Clavicular angle and
coracoid height difference can be used reliably to evaluate clinical shoulder balance. Although CTAD demonstrated
moderate correlation, it is still a valuable alternative when the shoulders are not completely seen on the X-ray.
Paper #10

**Hibbs Award Nominee for Best Basic Science Paper

Study of Pathomechanisms Initiating Scoliotic Deformities: Identification of a Novel Factor Essential for the
Initiation and Progression of Scoliosis

Bouziane Azeddine, M.Sc. (Universite De Montreal Research Centre Hopital); Hugo Boulanger; Sacha Blain;
Marc Limosani; Carl-Eric Aubin, PhD; Pierre A. Mathieu, PhD; Hubert Labelle, MD; Benoit P. Poitras, MD;
Charles-Hilaire Rivard, MD; Guy Grimard, MD; Jean A. Ouellet, MD; Keith M. Bagnall, MD; Alain Moreau, MD

a - Fondation Yves Cotrel, Institut de France

Introduction: Melatonin signaling dysfunction in AIS patients (Spine, 29:1772-1781, 2004)and melatonin
deficiency could both induce a scoliosis suggesting that the asymmetrical growth of the spine involves a common
downstream effector regulated by melatonin. This study was then designed to identify this triggering factor.

Methods: 100 newly hatched chickens underwent a complete removal of the pineal gland. Sham (n=20)and intact
chicken (n=25)were used as controls. All chicken underwent radiographic examination and were sacrificed at day 28
to collect tissues for RNA expression analysis by RT-PCR and proteins were examined by Western blot analysis.
Bipedal C57Bl/6 mice (n=50) were generated by surgery and examined by the same methods. Sera of mice, AIS
patients and matched healthy controls were also analyzed to determine the levels of circulating P factor using an
ELISA assay.

Results: A strong expression of a gene encoding a protein, termed P factor, was detected only in paraspinal muscles
of pinealectomized chicken developing a scoliosis. Accumulation of P factor was also confirmed at the protein level
by Western blot analysis. Bipedal C57Bl/6 mice, which are melatonin deficient, developed also scoliotic deformities
in a proportion of 45% over a 2-months period. Interestingly, genetically modified C57Bl/6 mice devoid of P factor
(n=60) or its receptor (n=40)did not develop a scoliosis. Moreover, P factor circulating levels in scoliotic patients
showed a 2-4 fold increase when compared to healthy matched individuals.

Conclusions: The study of molecular changes in animal models led us to identify a novel factor, which is essential
to initiate scoliosis through a specific signalling action. The clinical relevance of the P factor in AIS is further
strengthened by the detection of higher levels of P factor only in scoliotic patients and could lead to the development
of the first pharmacological therapies to prevent scoliosis formation or stop its progression.
Paper #11

“Spine at Risk Signs” to Predict Progression Of Deformity – A Study of the Natural History of Healed
Childhood Spinal Tuberculosis.

S Rajasekaran, MS, DNB, FRCS, MCh, PhD (Ganga Hospital)

Introduction: Post-tubercular kyphosis is unique as some children show spontaneous improvement while others
deteriorate.

Patients and methods: 63 lesions in 61 patients were followed up prospectively at 0, 3, 6, and 12 months and
yearly thereafter for 15 years. All patients were treated by ambulatory chemotherapy. Signs of instability were
dislocation of the facets, posterior retropulsion of the diseased fragments, lateral translation of the vertebrae in the
anteroposterior view and toppling of the superior vertebra. Each sign was allocated one point to create a spinal
instability score. The number of vertebral bodies involved was 2.33 and vertebral body loss was 1.6.

Results: The mean deformity increased from 35 to 41 over 15 years. While increase in deformity occurred in all
during the active phase of the disease, three types of progression were seen after healing - Type-I (n=25; 39%)
where deformity increased until growth had ceased. This was either continuous (type Ia; n=19) or after a lag period
of three to five years (type Ib; n=6). Type-II (n=27; 44%) progression showed decrease in deformity which could
occur immediately after the active phase (type IIa; n=9) or after a lag period of three to five years (type IIb; n=18).
Type-III progression (n=11; 17%) showed minimal change during either the active or healed phases and was seen in
patients with limited disease. Multiple regression analysis showed that a spinal instability score of more than 2 was a
reliable predictor for an increase of more than 30 deformity and a final deformity of over 60.

Conclusion: Signs of radiological instability appear early in the disease and they can be reliably used to identify
children who are at risk for late progressive collapse. Surgery is advised in these cases.
Paper #12

Validation of the SRS Adult Deformity Radiographic Classification

Thomas G. Lowe, MD (Woodridge Spine Center); Sigurd H. Berven, MD; Keith H. Bridwell, MD; Frank J.
Schwab, MD

Introduction: The adult with spinal deformity presents with clinical symptoms and radiographic findings that are
distinct from that of the adolescent with spinal deformity. Important differences include primary curve patterns,
coronal and sagittal imbalance, degenerative components within and outside the primary curve and regional sagittal
abnormalities. Existing classification systems have not dealt with the various components of the adult deformity.
The Adult Deformity Committee of the SRS has developed a radiographic classification specifically for adult
deformity.

Purpose: This classification system is designed to provide a radiographic framework for categorizing adults with
complex spinal deformities, which will be helpful in predicting treatment strategies.

Methods: Seven primary curve types were developed: 1) Single Thoracic, 2) Double Thoracic, 3) Double Major, 4)
Triple Major, 5) Thoracolumbar, 6) Lumbar, and 7) Primary Sagittal Deformity. Three modifiers were developed,
which include a Regional Sagittal modifier (upper thoracic, main thoracic, thoracolumbar, and lumbar), a Lumbar
Degenerative modifier (degenerative disc disease, listhesis, and fractional lumbosacral curve), and a Global Balance
modifier (sagittal and coronal). Erect long AP and Lateral radiographs of 25 adult spinal deformity cases were
reviewed by 17 SRS surgeons (including members of the SRS Adult Deformity Committee) for validation of the
system and prediction of instrumentation levels based purely on radiographic data.

Results: Kappa scores were calculated for the primary curve type (k=0.64), regional sagittal modifier (k=0.73),
degenerative lumbar modifier (k=0.65), global balance modifier (k=0.92), upper instrumented level (k=0.56), and
the lower instrumented level (k=0.77). See table 1 for the Kappa value scale.

Summary: Substantial interobserver reliability was noted when classifying complex adult deformities
radiographically by SRS surgeons. Clinical modifiers are currently being developed to help further define treatment
strategies in adult deformity patients.




                                   Table 1 - Kappa value scale
                             Kappa Value              Degree of Agreement
                                  0                            None
                                0-0.2                          Slight
                               0.21-0.4                         Fair
                               0.41-0.6                      Moderate
                               0.61-0.8                     Substantial
                               0.81-1.0                   Almost Perfect
Paper #13

Surgical treatment analysis of 809 thoracolumbar and lumbar major adult deformity cases by a new adult
scoliosis classification system

Frank J. Schwab, MD (Brooklyn Spine Center); Jean-Pierre C. Farcy, MD; Keith H. Bridwell, MD; Sigurd H.
Berven, MD; Steven D. Glassman, MD; William C. Horton, III, MD; Michael Shainline

a - Medtronic Sofamor Danek

Introduction: A recently proposed radiographic classification of adult scoliosis offers a reliable method of
categorizing patients. Continued work on this classification is expected to develop treatment guidelines. This
investigation analyzed treatment patterns of a large patient population of thoracolumbar and lumbar adult scoliosis,
emphasizing surgical rates and approaches by classification subtypes.

Methods: This investigation analyzed 809 Type IV (thoracolumbar major) and Type V (lumbar major) curves from
the Spinal Deformity Study Group database. Enrolled patients had complete SRS, ODI and SF-12 outcomes
questionnaires and free standing full-length spine radiographs. Analysis compared non-operative versus surgical
treatment (no imposed protocol) with surgical treatment assessed by approach (anterior, posterior, both), +/-
osteotomies.

Results: Of 809 patients, 348 were treated surgically (43%) and classified as lordosis type A (n=422), B (n=313), C
(n=74). Surgical rates were greater for B vs. A (51% vs. 37%, p 0.05)), trend for A vs. C (46%). Subluxation
modifier scores: 0 (n=360), + (n=159), ++ (n=290). Surgical rates were greater for ++ vs. 0 (52% vs. 36 %, p<0.05),
trend vs. + (42 %). Greater sagittal imbalance was more likely to receive surgical treatment. Loss of lumbar lordosis
(modifier B, C) was associated with increased osteotomy rates and posterior or circumferential treatment versus
anterior only procedures (most common in modifier A). Greater subluxation (modifier ++) was associated with more
circumferential surgery. Greater sagittal imbalance was associated with higher rate of posterior only surgery.

Discussion: In this analysis, greater lordosis or subluxation modifier score was associated with higher surgical rates.
Loss of lordosis and greater subluxation grade was associated with higher rates of circumferential surgery than
lordotic spines or those without significant subluxation. This information suggests the ability of this classification
system to predict treatment. Longitudinal follow up will permit validation of optimal treatment by classification of
adult spinal deformity.
Paper #14

Is the SRS-22 Instrument Responsive to Change (Surgical Treatment) in Adult Scoliosis Patients Having
Primary Spinal Deformity Surgery?

Keith H. Bridwell, MD (Washington University School of Medicine); Sigurd H. Berven, MD; Steven D.
Glassman, MD; Christopher L. Hamill, MD; William C. Horton, III, MD; Frank J. Schwab, MD; Christine Baldus,
LPN; Michael Shainline

a - Medtronic Sofamor Danek

Introduction: A number of efforts have been directed at validation of the SRS-22 instrument in the setting of adult
spinal deformity. However, no study has extensively analyzed the ability of the instrument to detect change (i.e.,
surgical treatment) in treated adult scoliosis patients. The purpose of this study is to prospectively analyze
responsiveness of SRS-22 to change (surgical treatment) at 1 and 2 years following surgery.

Methods: A multicenter prospective series of adult scoliosis patients (all primary/no revisions) were administered
SRS-22, ODI and SF-12 questionnaires preop and 1 and 2 years postop. 102 patients had 1-year follow-up, 39 had
2-year follow-up.
Demographics: 90% of patients were female, 10% male. 30% were 20-39, 48% were 40 to 60 and 22% were ≥61
years of age. The average preop Cobb was 59.5 and 29 at ultimate follow-up.

Results: The greatest changes from preop to 2-year follow-up were SRS appearance domain followed by SRS total,
SRS pain and ODI scores. These comparisons were the same at 1- and 2-year follow-up. The proportion of patients
meeting minimally clinically important difference (MCID) threshold at 1- and 2-year postop, respectively, were SRS
appearance (71%,76%), ODI (59%,73%), SRS pain (56%,63%), SF-12 physical (47%,56%) and SRS activity
(40%,42%). All outcome measures, except SF-12 mental health, showed statistically significant improvement from
baseline to 2-year follow-up. Strong correlation (Pearson’s correlation coefficients above r=0.8) was noted for SRS
pain, activity and appearance with total score and SRS activity and total score with ODI.

Conclusion: Based on these 3 outcome tools, the greatest responsiveness to change was demonstrated by SRS
appearance domain followed by SRS total, then SRS pain, then ODI. This suggests the SRS tool is more responsive
than ODI, which is more responsive than SF-12 to change brought on by primary surgical treatment of adult
scoliosis patients.
Paper #15

Why Adult Scoliosis Patients Choose Surgery

Steven D. Glassman, MD (Spine Institute); Frank J. Schwab, MD; Keith H. Bridwell, MD; Stephen L. Ondra,
MD; Sigurd H. Berven, MD; Lawrence G. Lenke, MD

a - Medtronic Sofamor Danek
d – Medtronic Sofamor Danek
e- Medtronic Sofamor Danek

Purpose: To define predictive factors which influence a patient’s decision to select surgical versus nonsurgical
treatment for adult scoliosis.

Methods: This is a retrospective case-control study of 161 matched surgical-nonsurgical pairs that were examined
based upon radiographic parameters, questionnaire responses, and standardized health status measures. Matching
was performed using logistic regression to allow matching based on age, gender, primary curve location and ODI.

Results: The surgical group had larger primary thoracic (51 versus 44 , p=0.006) and thoracolumbar/lumbar Cobb
angles (55 versus 43 , p=0.000). They also had significantly greater thoracolumbar/lumbar apical vertebral
translation (p=0.001). Comparison of pre-operative factors revealed that nonsurgical patients had a higher BMI
(p=0.03), a greater incidence of heart disease (p=0.04) and significantly poorer mean score on the SF-12 general
health subscale (p=0.01). Surgical patients had lower scores on SF-12 role physical (p=0.03) and SF-12 bodily pain
(p=0.04) scores.

There were significant differences with regard to the patients’ perception of appearance and social function between
the two groups. Surgical patients were more likely to report a change in their body shape over the past ten years (p
0.001), and were “very unhappy” with the shape of their back (p<0.001). Nonsurgical patients were more likely to
describe the appearance of their trunk as “good” while surgical patients were more likely to select “fair” (p=0.016).
Nonsurgical patients were more likely (39% versus 24%) to say that their back condition had no effect on their
personal relationships (p=0.03).

Discussion: This study offers a unique insight into surgical decision making for adult scoliosis patients based upon
patient based health status measures in a large sample of adult scoliosis patients. While this information is not a
substitute for long term prospective outcome data, it may help surgeons to better understand the patient/surgeon
decision making process and therefore to counsel patients more effectively.
Paper #16

Surgical Treatment of Adult Lumbar Scoliosis – Is Anterior Apical Release and Fusion Necessary?

Youngbae B. Kim, MD (Washington University School of Medicine); Lawrence G. Lenke, MD; Yongjung J.
Kim, MD; Young-Woo Kim, MD; Keith H. Bridwell, MD; Georgia Stobbs

a - Medtronic Sofamor Danek
d – Medtronic Sofamor Danek
e- Medtronic Sofamor Danek

Purpose: To analyze surgical outcomes in adult lumbar scoliosis following two different surgical techniques with
regard to whether an anterior apical release and fusion is necessary.

Methods: Thirty-eight patients with an average age of 49.7 years (range 22-77) and minimum 2-year follow-up
(average 3.8 years, range 2-10) were surgically treated for a lumbar scoliosis using two different techniques. In
Group I (n=18), anterior release was performed via a thoracoabdominal approach followed by posterior
instrumentation. In Group II (n=20), posterior correction and instrumentation was performed followed by anterior
column support through a separate anterior paramedian retroperitoneal or posterior transforaminal approach.
Preoperative and postoperative radiographs were evaluated and normalized SRS scores were used for clinical
evaluation.

Results: (See table) Groups I and II were well-matched preoperatively, except Group I patients had somewhat more
lumbar curve flexibility (P<0.02) and thoracolumbar kyphosis (P<0.02). Postoperatively, at last follow-up, there
were no significant statistical differences with regard to Cobb angle changes of the lumbar curve (P=0.19), fractional
lower lumbar curve (P=0.34), C7 plumbline to center sacral vertical line (P=0.30), C7 plumbline to the posterior
superior endplate of S1 (P=0.30), and sagittal Cobb angles at the proximal junction (P=0.95), T10-L2 (P=0.06) and
T12-S1 (P=0.56). Postoperative SRS scores at ultimate follow-up were significantly higher in Group II (P<0.05).
There were three pseudarthroses in Group I and only one in Group II.

Conclusion: For adult lumbar scoliosis, performing an apical release and fusion via an open thoracoabdominal
approach does not demonstrate any radiographic improvement over posterior fixation alone, which appears to have
superior clinical outcomes. Lumbosacral fusion should be performed via a separate anterior paramedian approach or
a posterior transforaminal approach.
                                           (Paper #16 attachment)

Table. Values for Treatment of Adult Lumbar Scoliosis

            Average Values                Group I           Group II   P-value
Age at surgery                             49.2               50.2      0.75
Lumbar curve (degrees)
   Preoperative                             60.7              55.8     0.19
   Flexibility (%)                          26.9              37.5     <0.02
   Final follow-up                          37.6              32.3     0.19
   Correction rate (%)                      39.0              42.1     0.50
Fractional lumbar curve (degrees)
   Preoperative                             34.7              31.9      0.39
   Final follow-up                          22.2              19.1      0.34
   Correction rate (%)                      43.5              39.0      0.41
C7-CVSL (mm)
   Preop.                                   24.8              22.6      0.70
   Final follow-up                          18.6              24.0      0.30
Sagittal Cobb angles at the proximal
junction (degrees)
   Preop.                                   2.06              1.90      0.93
   Final follow-up                          11.3              11.5      0.95
Thoracolumbar kyphosis;
T10-L2 (degrees)
   Preop.                                   27.7              14.8     <0.02
   Final follow-up                          21.4              10.9     0.06
Lumbar Lordosis; T12-S1 (degrees)
   Preop.                                   -42.1             -40.2     0.80
   Final follow-up                          -53.2             -49.3     0.56
C7-SSVL (mm)
   Preop.                                   2.11              4.20      0.87
   Postop.                                  -2.94             5.80      0.52
SRS-score (%)
   Preop.                                    61                65      0.36
   Postop.                                   70                78      <0.05
Paper #17

Adult Scoliosis Correction: Clinical and Radiographic Comparison of Techniques

Dennis G. Crandall, MD (Sonoran Spine Center); Matthew Morrison; Douglas Baker; Jan Revella; Claire Moore,
PA-C

a - Medtronic Sofomor Danek
d - Medtronic Sofomor Danek
e - Medtronic Sofomor Danek

Introduction: This study compares outcomes in patients with adult scoliosis treated with the new direct vertebral
translation technique compared to patients treated with rod derotation and in situ bending.

Methods: Sixty consecutive adult scoliosis patients age55(20-80yrs) underwent posterior correction by one surgeon,
followed 4yrs(2-11yrs). Seventeen used rod derotation and in situ rod bending. Forty-three used direct vertebral
translation by slowly pulling the spine to a contoured rod via pivoting reduction posts attached to screws,
simultaneously correcting both coronal and sagittal deformity. Two patients from each group required osteotomies.
Anterior surgery was required in 15/17 control and 39/43 direct translation patients. Oswestry, VAS, pain
medication use, and work status were followed along with radiographs. Clinical and radiographic results were
analyzed by curve type.

Results: The direct translation group curves of 49 (range17–83 ) corrected 72% to 14 (4-40 ) was better (P <0.01)
than control group curves of 55°(25–84°) corrected 48% to 29°(10-59°). Idiopathic scoliosis of 58°(43–83°) in the
translation group corrected 69% to 18°(7–40°) compared to 49% correction in the control group. Correction of
translation group vs control group by curve type was: degenerative 67%vs 49%, thoracic 70%vs51%, thoracolumbar
81%vs44%, lumbar 74%vs67% , double major 62%vs34% . Control group complications included 3 nonunions
(17%), 2 screw loosening (11%), 1 broken rod, 1 infection. The translation group had 4 nonunions (9%), 2
infections, no screw pullout. Eleven of 14 patients working pre-op returned to work. Oswestry and VAS score
improvements were not statistically different between groups at 1 and 2 years.

Conclusions: This study shows statistically improved correction of adult scoliosis by direct vertebral translation
using screws with pivoting reduction posts compared to other techniques. The most dramatic improvement was seen
in patients with thoracolumbar and lumbar scoliosis. The technique appears to be very promising in patients with
adult scoliosis.
Paper #18

The Lumbar Curve Response to Selective Thoracic Fusion in Adult Idiopathic Scoliosis

Michael W. Peelle, MD (Hospital for Special Surgery); Oheneba Boachie-Adjei, MD; Gina Charles; Addisu
Mesfin; Yamuna Kanazawa

Purpose: To determine the radiographic response of the lumbar curve in adult patients with idiopathic scoliosis
following selective thoracic posterior fusion and instrumentation with correlative clinical outcomes.

Methods: A retrospective, minimum 2-year follow-up, radiographic and clinical review of 30 patients with
adolescent-onset (21) and adult-onset (9) idiopathic scoliosis surgically treated at mean age of 40 years (20-66
years) using a posterior translational technique. End-instrumented vertebra were T11 (1), T12 (7), L1 (14), and L2
(8). Rib autograft via thoracoplasty and/or allograft was utilized in all patients. All patients had a preoperative MRI
to ensure disc integrity at end-instrumented levels.

Results: (See Table) At a mean follow-up of 39 (range 24-87) months, lumbar curve Cobb improvement (36 to 18
= 50% correction ) was less than the bending radiograph (12 , 68% correction). EIV tilt and disc angle significantly
improved, whereas lumbar AVT and apical disc angle improvement was minimal. Coronal imbalance of >2cm was
present in 6 patients at final follow-up. One patient required extension to the lumbar curve 4 years post-operatively
due to continued pain. Mean subgroup scores of the SRS-22 questionnaire were 3.8 ± 0.9 for pain, 4.0 ± 0.5 for self-
image, 4.2 ± 0.8 for function, 3.8 ± 0.7 for mental health, and 4.1 ± 0.6 for satisfaction.

Conclusion: The lumbar curve response in adult, selective thoracic scoliosis surgery is characterized by:
1) moderate correction but less than the bending film Cobb
2) greater change in EIV tilt and EIV disc angle than apical vertebra disc angle
3) no change in lumbar AVT or lumbar rotation
4) more significant disc height preservation at the EIV compared to lumbar apex
Adult AIS patients should be offered selective thoracic fusion to preserve motion segments; however, they should be
apprised of potential degeneration requiring an extension of the fusion.
                                          (Paper #18 attachment)

Table: Radiographic Measurements of 30 Adults Undergoing Selective Thoracic Fusion.   P-values compare pre-
operative and latest follow-up values.
                                         Pre-op              Post-op                  Latest Follow-up        p-value
Lenke Lumbar Modifier “A”                        12                   12                        17
                           “B”                   13                   13                        9
                           “C”                   5                     5                        4
Proximal thoracic Cobb                   33° (16-60)         23° (0-40); 32%          21° (8-82); 38%         <0.001
Main thoracic Cobb                       62° (33-90)         23° (10-40); 62%         27° (10-48); 57%        <0.001
Lumbar Cobb                              36° (18-61)         18° (2-36), 50%          18° (2-44); 50%         <0.001

Thoracic Apical Vertebral Translation      50.5 (19-54)      14 (1-47), 74%           14.1 (1-39); 72%        <0.001
(AVT) (mm)
Lumbar AVT (mm)                            17.3 (1-33)       17.4 (2-41); -1%         17.1 (2-48); 1%         0.23
Lumbar rotation (Pedriolle method)         8.2° (0-25)       9.9° (0-22)              9.9° (0-35)             0.11
End-instrumented vertebra tilt angle       24.4° (3-58)      8° (1-17); 67%           9° (2-20); 63%          <0.001
EIV disc angle                             7.8° (0-18)       4.8° (0-15); 38%         4.1° (0-12); 47%        <0.001
EIV disc height, concave side              5.9               6.4                      6.7                     0.002
    (mm)          convex side              9.8               7.9                      7.6                     0.14
Lumbar apex disc angle                     9.8° (5-18)       7.1° (1-19); 28%         7.4° (1-19); 25%        <0.001
Lumbar apex disc height, concave           5.3               6.7                      5.7                     0.01
     (mm)                 convex           9.6               9.2                      8.3                     0.23
Kyphosis (T2-T12)                          39° (18-60)       29° (16-51)              33° (17-55)             0.01
Lordosis (T12-S1)                          62° (40-83)       52° (26-75)              58° (40-75)             0.01
Coronal balance (mm)                       -4.2 (-34-67)     -13.6 (-39-10)           -12.4 (-36-9)           0.01
Sagittal balance (mm)                      -27 (-130-75)     -7 (-112-90)             -22.5 (-62-17)          0.77
Paper #19

**Hibbs Award Nominee for Best Clinical Paper

Is the T9, T11, or L1 proximal level the more stable following lumbar/lumbosacral fusions from the
thoracolumbar junction to L5-S1?

Yongjung J. Kim, MD (Washington University School of Medicine); Keith H. Bridwell, MD; Lawrence G.
Lenke, MD; Seungchul Rhim, MD; Young-Woo Kim,

Purpose: To compare the postoperative proximal junctional change, thoracic kyphosis progression, and sagittal
vertical axis change according to the three different proximal levels following adult lumbar deformity
instrumentation and fusion from the thoracolumbar spine to L5-S1.

Methods: A radiographic and clinical outcome assessment of 90 adult lumbar deformity patients (average age 55.0
years) who underwent long posterior spinal instrumentation and fusion from the thoracolumbar spine to the L5- S1
with a minimum 2-year follow up (2-15.8 year follow-up) was compared according to T9/T10 (Group1, n=25),
T11/T12 (Group 2, n=35), and L1/L2 (Group 3, n=30) proximal fusion levels. Proximal junctional kyphosis (PJK)
was defined by proximal junction sagittal Cobb angle between the lower end plate of the uppermost instrumented
vertebra and the upper end plate of 2 supradjacent vertebra ³ +10 degrees and at least 10 degrees greater than the
preoperative measurement at the ultimate follow-up.

Results: Three group demonstrated similar follow-up (p=0.41), different age at surgery (Group1 48.2 years vs.
Group 2 55.3 years vs. Group 3 60.9 years, p<0.001), nonsignificant differences in the postoperative thoracic sagittal
Cobb angle progression (p=0.14), proximal junctional angle change (p=0.34), and sagittal vertical axis change
(p=0.09) at the ultimate follow-up. The prevalence of the PJK demonstrated no significant relation among 3 groups
(p=0.65), preoperative sagittal imbalance (C7 plumb > 8cm vs <8cm, p=0.39), and older age at surgery (>55 years
vs. 55 years or below, p=0.32). Proximal junctional angle (PJA) change demonstrated positive correlation with
ultimate PJA (R=0.531, p<0.0001), ultimate thoracic kyphosis progression (R=0.488, p<0.0001), and negative
correlation with preoperative PJA (R=-0.330, p=0.002). The SRS outcome scores did not demonstrate significant
differences (p=0.31). (See Table).

Conclusion: Three different proximal fusion levels did not demonstrate significant radiographic and clinical
outcomes differences postoperatively. Therefore the more distal proximal fusion level at a neutral and stable
vertebra is satisfactory.

Sagittal balance after lumbar/lumbosacral fusion
Table. Comparison among three different proximal stops.

                                                T9/T10            T11/T12          L1/L2        P value
                                                 (n=25)            (n=35)          (n=30)
Age at surgery (years)                          48 +12.3          55 +11.8        61 +10.8      <0.001

Follow-up (years)                               5.0 + 8.84        4.3 + 2.19      5.2 + 2.67      0.41

PJA increase at ultimate FU                      8 + 6.5°         10 + 10.9°     12 + 10.4°       0.34

TK increase at ultimate FU                      13 + 12.6°        13 + 11.5°      6 + 15.5°       0.14
SVA increase at ultimate FU(cm)                  -5 + 8.6          -1 + 6.6        0 + 6.0        0.09

SRS 24 outcome score                            88 + 23.3         84 + 18.4       93 + 15.1       0.31
PJA = Proximal junctional angle, FU = Follow-Up, TK = Thoracic Kyphosis (T5-T12), SVA = Sagittal
Vertical Axix, SRS = Scoliosis Research Society
Paper #20

Proximal Junctional Kyphosis following Adult Spinal Deformity Long Posterior Segmental Instrumentation
and Fusion: Minimum 5 years follow-up

Yongjung J. Kim, MD; Keith H. Bridwell, MD; Lawrence G. Lenke, MD; Seungchul Rhim, MD (Asa Medical
Center); Gene Cheh, MD


Purpose: To analyze the time-dependent change, prevalence of and risk factors for proximal junctional kyphosis in
adult spinal deformity following long (> 5 vertebrae) segmental posterior spinal instrumentation and fusion with a
minimum 5 years postoperative follow-up.

Methods: Clinical and radiographic data of 90 (59 female and 31 male) adult deformity patients with a minimum 5
years follow-up (average 7.0 years, range 5-16 years) treated with long posterior spinal instrumentations and fusion
were analyzed. Radiographic data included sagittal parameters. SRS outcome scores at the ultimate follow-up were
evaluated. Abnormal PJK was defined by the proximal junction sagittal Cobb angle between the lower end plate of
the uppermost instrumented vertebra and the upper end plate of 2 supradjacent vertebra ³ +10 degrees and at least 10
degrees greater than the preoperative measurement at the ultimate follow-up.

Results: The prevalence of the PJK at 7.0 years postoperative was 39% (35/90 patients). PJK group (n=35)
demonstrated significant increase in proximal junctional angle at 2 years postoperation and at the ultimate follow-up
(p < 0.0001 and p55 years vs. 55 years or below) demonstrated significantly higher PJK prevalence (p=0.039 and
p=0.044 respectively). The SRS outcome scores did not demonstrate significant differences.

Conclusions: The prevalence of proximal junctional kyphosis at 7.0 years postoperation was 39% and progressed
slightly after 2 years postoperation. All pedicle screw instrumentation and age at surgery (>55 years) were identified
as risk factors for developing PJK. The SRS 24 outcome instrument was not affected by PJK.
Paper #21

Proximal Junctional Kyphosis in Adult Spinal Deformity:Comparison of Hook versus Pedicle Screw
Constructs

Ronald A. Lehman, Jr., MD; Keith H. Bridwell, MD; Kathryn Keeler, MD (Washington University School of
Medicine); Gene Cheh; Jacob Buchowski, MD; Craig A. Kuhns, MD; Lawrence G. Lenke, MD

Objective: To analyze the intermediate-term follow-up of matched groups (pedicle screws vs.hooks) in adult
deformity patients in terms of radiographic parameters, junctional kyphosis and complications.

Background Data: The comparison of hook versus screw constructs in terms of proximal junctional
kyphosis(PJK)in adult spinal deformity patients has never been analyzed.

Methods: 123 consecutive patients (Group-1-79 pedicle screw constructs vs. Group-2-44 hook constructs) with a
diagnosis of adult scoliosis having 2-year follow-up(mean=5.63+2.45SD yrs) were evaluated. Sagittal plane
radiographic measurements were analyzed. Proximal junctional kyphosis was defined as the Cobb angle between the
inferior endplate of the upper instrumented vertebrae(UIV) and the superior endplate of two levels cephalad to the
UIV measuring >10 and having an absolute value of >10 . Significance was defined as p<0.05.

Results: The prevalence of PJK was 36.6%(45/123pts) overall, with 38% in Group-1(Screws) and 34% in Group-
2(Hooks)(p=0.11). Using prior surgery, age and osteotomy as a covariate, Group-1(Screws) demonstrated a
significant increase in PJK preoperatively to postoperatively, and progressed until FFU(p<0.0001). Group-2(Hooks)
showed a significant increase preop to postop, with maintenance until FFU(p<0.0001 and p=0.08,respectively).
Group-2(Hooks) did not show any significant change in the C7 sagittal alignment, while Group-1(Screws) showed a
significant negative balance in C7 plumb postoperatively, with progression towards a positive balance at
FFU(p<0.0001). In terms of thoracic sagittal alignment(T5-12), Group-2(hooks) did not change immediately
postoperatively, but did develop progressive kyphosis at FFU(p=0.01), while Group-1(Screws) demonstrated a
significant change initially, but maintained their correction(p=0.0001). Confounding variables such as smoking,
complications nor SPO’s influenced either group.

Conclusions: At an average of 2.5-years of follow-up, the overall incidence of proximal junctional kyphosis was
36.6%, averaging 38% in Group-1(Screws) and 34% in Group-2(Hooks) after prior surgery, age and osteotomy were
subtracted out as a covariate. Although PJK was nearly equal in both groups, PJK continued to progress
postoperatively in the hook patients, but not in the screw group.
Paper #22

Thoracolumbar Deformity Arthrodesis Stopping at L5: Fate of the L5-S1 Disc with a Minimum 5-year
Follow-up

Craig A. Kuhns, MD (Washington University School of Medicine); Keith H. Bridwell, MD; Lawrence G.
Lenke, MD; Courtney Amor; Ronald A. Lehman, Jr., MD; Jacob Buchowski, MD; Christine Baldus, LPN;
Charles Edwards, II, MD

Background: Two previous studies reported the results of long deformity fusions terminating at L5 with minimum
2-year follow-up only.

Purpose: Evaluate the fate of L5-S1 disc analyzing subsequent disc degeneration and associated risk factors for
degeneration.

Methods: Thirty consecutive patients with an average age 45years(20-62yo)were fused from the thoracic spine to
L5 and were evaluated at a mean follow-up of 8.7 years(5-15.5). Patients were evaluated preoperatively,
postoperatively, and latest follow-up with radiograps and SRS scores. Disc degeneration utilizing validated
radiographic Weiner grades. Grade 0-1 discs were “healthy” and grade 2-3 were degenerated. Patients with
“healthy” discs preop that subsequently degenerated were designated subsequent advanced degeneration(SAD).

Results: 2/30 patients had preoperative advanced degeneration of the L5-S1 disc(Weiner Grade 2-3). 28/30 patients
were assessed as “healthy discs” preop (Weiner Grade 0-1). By latest follow-up, subsequent advanced L5-S1 disc
degeneration(SAD) developed in 19 of these 28 patients(68%) who had “healthy” discs. Younger age at the time of
surgery is an associated risk factor for developing SAD(p=0.04). Preop sagittal balance was not significantly
different between those patients that developed SAD and those who did not. 17/30 patients(57%) were noted to have
sagittal imbalance >5cm at follow-up. At most recent follow-up the average sagittal imbalance in the SAD group
was 72mm. In the “healthy” group it was 3mm (p=0.001). 6/30 patients(20%) were revised with extension to the
sacrum. There was a trend toward inferior SRS pain scores at follow-up in SAD patients(avg. score—4.0 vs
3.2,p=0.08).

Conclusion: Advanced L5-S1 DDD developed in 68% of deformity patients after long fusions to L5 with 5-15 year
follow-up. SAD frequently results in significant positive sagittal balance with minimum 5year follow-up.
Paper #23

Surgical Outcomes of Revision Surgery Extended to Sacrum For Post-Surgical Junctional Degeneration in
Adults

Masayuki Ishikawa, MD; Oheneba Boachie-Adjei, MD; Matthew Cunningham, MD, PhD; Gina Charles

e – DePuy Spine

Purpose: To assess differential outcomes for surgical revision technique used in fusion extensions to the sacrum for
post-surgical junctional degeneration.

Materials and Methods: 23 consecutive adult patients (average age 48) underwent revision surgery using either
combined anterior-posterior spinal fusion (APSF) or posterior spinal fusion with posterior lumbar interbody fusion
with or without pedicle subtraction osteotomy (PSF-PLIF). Follow-up averaged 3.9 years (range, 2-9.7 years). Prior
fusions extended from the thoracic region to L3, 4, or L5. Radiographs were reviewed for sagittal and coronal
balance, and lumbar curve magnitude. Complications were tabulated and functional outcomes were assessed using
SRS-22 questionnaire. Group 1 was APSF (N=13) and Group 2 was PSF-PLIF (N=10).

Results: Mean fusion levels for Group 1 and 2 were 4.5 and 1.8, respectively. Cobb values for Groups 1 and 2
averaged 38.8 and 52.5 degrees preoperatively, and corrected by 16 and 15% postoperatively, respectively. Coronal
balance in Groups 1 and 2 averaged -6mm and 0.7mm preoperatively, and were -8.7mm and -1.7mm
postoperatively, respectively. Likewise, sagittal balance averaged 70mm and 65mm in Groups 1 and 2
preoperatively, and 26mm and 13mm postoperatively, respectively. Nine major complications were observed in six
patients (26%), including one deep wound infection (Group 1), one neurological compromise (Group 2), two
proximal junctional kyphosis, and five implant failures (3 in Group 1). There were also 2 dural tears in Group 1.
SRS-22 scores at final follow-up averaged 4.0 in Group 1 and 3.5 in Group 2.

Conclusion: Overall, comparable improvement of deformity and balance, and patient satisfaction was seen in both
groups. Further work is necessary, but these findings suggest that if a simple extension of an acceptable fusion mass
is required for a revision extension then PSF/PLIF/PSO is an acceptable option, but if revision of the fusion mass is
required then APSF is required.
Paper #24

**Hibbs Award Nominee for Best Clinical Paper

A Large-Scale, Level 1, Clinical And Radiographic Analysis of an Optimized rhBMP-2 Formulation as an
Autograft Replacement in Posterolateral Lumbar Spine Fusion

John R. Dimar II, MD (Spine Institute); Steven D. Glassman, MD; J. Kenneth Burkus, MD; Philip W. Pryor;
MD, James W. Hardacker, MD; Scott D. Boden, MD

a - Medtronic Sofamor Danek
e - Medtronic Sofamor Danek

Purpose: To determine the feasibility of using recombinant human bone morphogenetic protein-2 with a
compression resistant matrix (rhBMP-2/CRM) as an iliac crest bone graft (ICBG) substitute in patients undergoing
posterolateral fusion.

Methods: In this ongoing prospective study, 463 patients with symptomatic single-level degenerative disc disease
with ≤ Grade1 spondylolisthesis were treated with decompression and instrumented single-level posterolateral
fusion through an open midline approach. Patients were randomly assigned to either the rhBMP-2/CRM
(AMPLIFY™, Medtronic Sofamor Danek) group (239 patients) or the ICBG group (224 patients). ODI, SF-36, and
back and leg pain scores were determined preoperatively and at 1.5, 3, 6, 12 and 24 months postoperatively. Two
independent radiologists reviewed radiographs and CT scans taken at 6, 12, and 24 months postoperatively. Fusion
was defined as the presence of bilateral, continuous trabeculated bone connecting the transverse processes and
translation of ≤3 mm and angulation of <5° on flexion-extension radiographs.

Results: No significant differences in demographics existed between the groups. Mean operative time in the
rhBMP-2 group (2.5 hours) was less than in the ICBG group (2.9 hours) (p<0.001). Average blood loss in the
rhBMP-2 group was 343.1 mL compared with 448.6 mL in the ICBG group (p<0.001). Average hospital stay was
similar in both groups. No differences existed between groups in adverse events except nonunion rate was lower in
the rhBMP-2 group (2.5%;6 patients) than in the ICBG group (7.1%;16 patients) (p=0.042). At 12 months, 87.4% of
patients in the rhBMP-2 group and 82.4% in the ICBG group had evidence of fusion (p=0.1992). At 24 months,
94.9% in the rhBMP-2 group were fused compared with 86.8% in the ICBG group (p=0.0737). Both groups showed
similar improvements in clinical outcomes and reduced pain.

Conclusions: The use of rhBMP-2 can eliminate the need for harvesting iliac crest bone in successful posterolateral
lumbar fusions.



** The FDA has not cleared a drug and/or medical device described in this presentation (i.e., the drug or medical
device is being discussed in an (off-label use.) For full information refer to page 5
Paper #25

**Hibbs Award Nominee for Best Basic Science Paper

Can rhBMP-2 Overcome the Inhibitory Effect of Alendronate Sodium on Spinal Fusion?

Timothy R. Kuklo, MD, JD (Walter Reed Medical Center); Anton E. Dmitriev; Christopher J. Neal, MD;
Norman Gill; Ammon Brown; Ronald A. Lehman, Jr, MD

a - Medtronic Sofamor Danek

Purpose: To determine if rhBMP-2 can overcome the inhibitory effect of alendronate sodium on spinal fusion.

Materials and Methods: Sixty New Zealand white rabbits underwent a L4-L5 posterolateral /inter-transverse
process fusion (n=15/group): Group I- iliac crest autograft control; Group II - autograft + Fosamax; Group III -
rhBMP-2 control; Group IV- rhBMP-2 + Fosamax. Based on allometric calculations, rabbits were administered
either 1.4mg/animal/dose of alendronate sodium (Grps II+IV) or saline via oral gavage.

Results: Fifty-four rabbits completed the study, Grp I- 13, Grp II - 14, Grp III - 12 and Grp IV- 15 rabbits. By
palpation, 72% were considered fused (54%, 43%, 100% and 100% respectively; p 6.5 ROM in flexion-extension
as a criteria for pseudarthrosis, inter-group fusion was present in 54%, 36%, 100% and 100% respectively. Both
rhBMP-2 groups exhibited significantly lower ROM in each testing mode (flexion-extension, lateral bending,
rotation), even when compared to “fused” specimens in Grp I and II (p0.05 for all comparisons of Grp I vs. Grp II,
or Grp III vs. Grp IV). Histologically, successful bony union was observed in 54%, 43%, 100% and 100% of cases
respectively.

Conclusions: The rhBMP-2 control group showed a 100% fusion rate; however, surprisingly the rhBMP-2 +
Fosamax group also showed a 100% fusion rate, with an average Emory score, radiographically evaluated bridging
bone, and biomechanical testing which was slightly better than the Fosamax control group. Thus, rhBMP-2 can
overcome the inhibitory effect of Fosamax in a rabbit PL fusion model, as well as have a synergistic effect on spinal
fusion. This implies that Fosamax may NOT need to be discontinued in clinical practice when a spine fusion is
contemplated.
Paper #26

Rib-Strut Graft for Pediatric Spinal Deformity: A Comparison Between Vascularized and Non-Vascularized
Rib Graft

Daniel J. Sucato MD, MS (Texas Scottish Rite Hospital for Children); Nathan Gilbert

Purpose: To compare the radiographic and clinical outcome of patients who had a rib-strut graft for pediatric
kyphosis comparing non-vascularized rib graft (NVRG) to vascularized rib graft (VRG).

Methods: An IRB-approved retrospective review of all patients at a single institution who had a rib-strut graft
placed for pediatric spinal deformity was performed. The medical record was reviewed for demographic data, date
of surgery, complications, postoperative follow-up. The radiographs were reviewed preoperatively, postoperatively,
and at minimum two-year follow-up. The two groups were compared statistically.

Results: There were 32 patients in the NVRG group and 20 patients in the VRG group. The average age of the
patients in the NVRG group was younger (9.3 vs. 12.3 years). The body mass index (21.4 vs. 23.0cm/kg2), weight
(35.1 vs. 42.1 kg), the number of anterior levels fused (4.9 vs. 5.1), and the levels in which the strut was placed (4.7
vs. 5.1) were similar between the NVRG group and the VRG groups. However, the NVRG group had less blood loss
(362 vs 504 ccs), and the anterior surgical time was less (216 vs 282 minutes) (p=0.002). The radiographic
assessment demonstrated no difference between the NVRG and VRG groups with respect to preoperative kyphosis
(61.4º vs 71.2º), postoperative kyphosis (57.2º vs. 59.8º), 1 year (55.0º vs. 59.5º) and 2 year kyphosis (54.8º vs.
60.0º). There was no difference between the NVRG and the VRG groups in the time to union of the anterior strut
graft (4.5 vs. 4.4 months) (p=0.83) or the incidence of complications.

Conclusions: The use of a vascularized rib strut graft does not seem to offer any distinct advantages when compared
to a rib strut graft without a vascular pedicle in pediatric spinal deformity.
Paper #27

VEPTR to treat non-syndromic congenital scoliosis: a multicenter, mid-term follow-up study

John M. Flynn, MD (Children’s Hospital of Philadelphia); Rebecca Gaugler, John B. Emans, MD; John T.
Smith, MD; Randal R. Betz, MD; David L. Skaggs, MD; Kit M. Song, MD; Morey L. Moreland, MD; Robert M.
Campbell, Jr., MD

e – Synthes Spine

Purpose: Traditional surgical management of congenital scoliosis in young children, including fusion in-situ and
hemiepiphyseodesis, did not promote spinal growth nor address the associated thoracic insufficiency. We
hypothesize that VEPTR with expansion thoracoplasty may control the spinal deformity, allow spinal growth, and
address thoracic insufficiency in children with complex congenital spinal deformities.

Materials: Seven pediatric spine centers prospectively entered clinical and radiographic data into a database on
every congenital spinal deformity treated with VEPTR as part of an FDA study. Patients with spina bifida, Jarcho-
Levin or other syndromes were eliminated from this series. Data analysis focused on surgical technique and
expansion frequency, change in Cobb angle and thoracic height, and adverse events for a consecutive series of
patients with at least 2 years of follow-up.

Results: 24 children, with an ave. age at surgery 3.3 years (range 1.0 yrs – 12.5 yrs), were treated with VEPTR
insertion and expansion thoracoplasty and followed for an ave. of 40 mos. (range 25-78 mos.). 23/24 had associated
rib fusions. All patients had subsequent expansion surgery; 50% had 5 or more expansions. 20/24 (83.3%) had
improvement in Cobb angle during treatment; the ave. overall change was -8.9 . 23/24 had an increase in thoracic
height, ave. 2.6 cm during the treatment period. 17/24 had at least 1 adverse event, the most common being device
migration in 7, and infection or skin problems in 6.

Conclusion: VEPTR insertion and expansion thoracoplasty represents a new treatment paradigm for congenital
spinal deformities. We report the first multicenter data, with mid-term follow-up. The vast majority of patients had
improvement in Cobb angle and thoracic height over the treatment period. Challenges include the demands of
multiple procedures, skin problems and device migration.
Paper #28

**Hibbs Award Nominee for Best Clinical Paper

Spinal Growth after Transpedicular Instrumentation in One and Two Year Old Children – a Ten Year
Follow-up

Michael Ruf, MD (Klinikum Karlsbad); Juergen Harms, MD

Introduction: Congenital deformities should be corrected early before rigidity increases and before secondary
structural curves develop. However, in young children the immature posterior elements do not allow for a stable
fixation with hooks or wires. In a one or two year old child transpedicular instrumentation is the only option which
ensures stable fixation. There is, however, a lack of long-term results regarding vertebral growth following
transpedicular instrumentation in this age group.

Methods: Twenty-two operations in 19 one and two year old children were performed between 1991 and 2003. A
total of 120 transpedicular screws were inserted; 20 in the upper thoracic spine (T1-T4), 26 in the midthoracic spine
(T5-T9), 53 in the thoracolumbar region (T10-L1), and 21 in the lumbar spine (L2-S1). Screw diameter was 3.5 mm.

Five patients (group 1) were evaluated with a minimum follow-up of 10 years, 14 patients (group 2) with a follow-
up of 2 to 10 years.

Results: None of the patients showed neurologic deficits, neither by placement of the screws nor during further
growth. MRI or CT studies were performed in 3 patients of group 1; they showed no stenosis of the spinal canal.
Radiographic results demonstrated growth of the instrumented vertebral bodies comparable to adjacent vertebrae.
Complications of pedicle screws: 6 malpositions (5%), 2 screw breakages (1.7%), and one pedicle fracture (0.8%).

Discussion: The results suggest that pedicle screw fixation can be performed safely in one and two year old children
without adverse effects on vertebral growth. Transpedicular screws allow for stable fixation with three dimensional
control of the vertebral body and transmission of adequate correction forces. Although transpedicular screws cross
the neurocentral synchondrosis, no stenosis of the spinal canal was observed. Vertical growth of the vertebral bodies
against posterior transpedicular instrumentation, which acts as a tension band, results in increasing lordosis.
Paper #29

Change in Pulmonsry Function after VEPTR Insertion

Oscar H. Mayer, MD (The Children's Hospital of Philadelphia); Gregory Redding, MD

b – Synthes Spine

Introduction: The vertical expandible prosthetic titanium rib (VEPTR) has been inserted in children with thoracic
insufficiency syndrome for the last decade to expand and support the chest and allow for further lung growth.
Thought there is clincal and radiographic evidence demonstrating an expansion in the thorax, there is a paucity of
data on the post-operative change in lung function after VEPTR insertion.

Hypothesis: There will be a significant increase in lung function after VEPTR insertion and the earlier the insertion
the greater the improvement.

Methods: The Chest Wall Disorders Study Group Database was queried and spirometry was available on 56
subjects and lung volume measurements on 12 subjects before and after VEPTR insertion at 7 different centers.

Results: There was no statistically significant change in FVC, FEV1, total lung capacity, or residual volume after
VEPTR insertion by two-tailed t-test when measured at the first post-operative visit (7.7 ± 4.8 months). There was
no difference relative to diagnosis or correlation between absolute change in pulmonary function and age.

Conclusion: There is no significant improvement in lung function after VEPTR surgery. Age has no impact on the
change in pulmonary function after surgery.

Speculation: This lack of change in pulmonary function after VEPTR insertion may mean that the improvement
may occur over a longer period of time, or that the benefit may instead be preservation of lung volume.
Paper #30

Health Related Quality of Life in Children with Thoracic Insufficiency Syndrome

Michael G Vitale MD (Children's Hospital of New York –Presbyterian); David P. Roye, Jr., MD; Hiroko
Matsumoto, Randal R. Betz, MD; John B. Emans, MD; David L. Skaggs, MD; John T. Smith, MD; Kit M. Song,
MD; Robert M. Campbell, Jr, MD

a - Synthes Spine
b - Synthes Spine
c - Synthes Spine

Purpose: In contrast to children with adolescent idiopathic scoliosis, children with early onset scoliosis often have
significant comorbidities and can rapidly develop thoracic insufficiency and pulmonary compromise which has a
profound effect on their lives. The traditional surgical or non-surgical techniques to treat Thoracic Insufficiency
Syndrome (TIS) are not able to stabilize or improve chest wall size or pulmonary function while allowing spine
growth. To this end, Vertical Expandable Prosthetic Titanium Rib (VEPTR) was specifically designed to treat TIS
by allowing growth of the thoracic cavity and control/correction of spine deformity. The purpose of this study is to
compare quality of life (QOL) of children with TIS, prior to implantation of VEPTR, with previously published
QOL of healthy children as well as to that of children with other diseases.

Method: As part of the original multicenter evaluation of the VEPTR, Child Health Questionnaire (CHQ) was
collected preoperatively on forty five patients who were subsequently treated with expansion thoracoplasty using the
VEPTR. The average age was 8.2±2.6 and parent form of the CHQ was filled out by the primary caretaker. Patients
were divided in to three broad diagnostic categories; Rib Fusion (RF, N=15), Hypoplastic Thorax Syndromes (HT,
N=17) and Progressive Spinal Deformity (PS, N=13).

Results: There were significant differences between the study patients and healthy children in Physical Functioning,
Role/Social Limitations-Physical, General Health Perceptions, Parental Impact-Emotional, Parental Impact-Time,
Family Activities, Physical Summary, and Psychosocial Summary (Table).

Discussion: Patients with thoracic insufficiency syndrome have significant and profound perturbations in QOL
when compared with other children. These scores are among the lowest observed in pediatric populations. Current
efforts are underway to better understand the clinical features that have the most profound effects on the life of these
children. Finally, these data will serve as an important baseline on ongoing studies of these patients after expansion
thoracoplasty.

                                        RF                   HT                  PS               Norms
                                     Mean(SD)            Mean(SD)            Mean(SD)            Mean(SD)
Physical Functioning                81.3(22.7) *        66.0(30.1)**        53.5(37.0) **        96.1(13.9)
Role/Social Limitations –
Physical                             97.8(8.6)           67.6(37.0)*          74.4(40.6)         93.6(18.6)
General Health Perceptions
                                     62.7(20.1)        45.8(19.9)***         50.1(18.9)**        73.0(17.3)
Parental Impact
–Emotional                         52.3(29.9)**        57.8(27.9)**          46.8(29.8)**        80.3(19.1)
Parental Impact –Time              56.3(23.6)***       54.7(24.7)***         60.4(20.8)**        87.8(19.9)
Family Activities                   78.3(19.7)*         74.7(24.7)*           77.4(28.5)         89.7(18.6)
Physical Summary                     47.4(8.3)*         32.2(20.1)**         30.2(14.7)**        53.0(8.8)
Psychosocial Summary                45.4(5.9)**           48.9(6.1)            47.1(8.3)          51.2(9.1)
*p<.05. **p<.01. ***p<.001.
Paper #31

Four Thousand Wires Under The Lamina

Abhay Nene, MS (Spine Clinic, P D Hinduja National Hospital); Shekhar Bhojraj, MS, FCPS, DOrtho; Sheetal
Mohite, DNB; Raghuprasad Varma, MD

Background Context: Sub laminar wiring (SLW) has been labeled as a neurologically hazardous technique of
spinal fixation based on few repeatedly cited reports, most of which are over two decades old. There are few modern
reports about the safety of SLW.

Purpose: To evaluate the neurological safety of SLW.

Study Design: This clinical study is a retrospective analysis of 273 consecutive patients in whom 4275 sub laminar
wires were used for spinal fixation for varying etiologies.

Outcome Measures: Frankel grading was used to quantify pre and post operative neurological status.

Methods: An independent observer analyzed 273 successive patients operated using SLW between May 1993 to
June 2004 at our clinic. Follow up period ranged from 2 to 12 years. These consisted of 90 deformities, 45 tumors,
38 fractures and 100 infections.
Pre and postoperative neurological status (using Frankel’s grading) was documented in each patient.

Indications for SLW, levels and number of wires used in each case were also noted.

Results: 175 of the 273 patients had some neurological deficit at the time of surgery (Frankel A = 39, Frankel C =
111). 143 of the 175 patients with pre operative neurological deficit showed neurological recovery post operatively,
of which 107 had a recovery of over 2 Frankel grades.
Fifteen patients with a pre op Frankel A (total sensori motor deficit) regained functional power (grade C or more)
post operatively.

31 of the 175 patients remained unchanged neurologically post op.

1 patient developed an implant related cord deficit post operatively, unreleated to he wiring.

No patient had any major wire related neurological complications.

Two patients developed transient radicular paraesthesiae post op, which recovered.

Conclusions: Sublaminar wiring is a safe technique, if done using the correct principles and techniques, in the
correct indications.
Paper #32

Correlation Between Neurologic Recovery And Timing Of Surgical Decompression Of Post-Operative Spinal
Epidural Hematoma (POSEH)

Khaled M Kebaish, MD, FRCSC (Johns Hopkins University); John Awad, MD; Jonathan Donigan, Richard
Skolasky Jr.

Background: The incidence of postoperative spinal epidural hematoma requiring evacuation ranges from 0.1% to
3%. Although rare, these haematomas can have devastating consequences. Studies of the effect of the magnitude and
duration of cord compression in humans have produced conflicting results.

Purpose: Identify the correlation between neurologic recovery and timing of surgical decompression of(POSEH}.

Methods: 14,932 patients underwent spinal surgery between 1984 to 2002 at our institution and met the inclusion
criteria. 32 patients (0.2%) developed POSEH and had some degree of neurological compromise.

Results: The average time between surgery and evacuation of the hematoma was 79.9 hours. The average time from
onset of symptoms to second operation was 18.6 hours. There was no difference in bowel or bladder dysfunction
across time categories at preoperative (Chi-square (3 d.f.) = 5.00, p=.172) or at first day postoperative (Chi-square (3
d.f.) = 3.41, p=.332). There was no correlation between time from surgery to symptoms and neurologic recovery
(NR). There was no correlation between age and (NR)(rho=.001, p=.995), time from index surgery to symptoms
(rho=0.064, p=.737). There was no gender correlation. The change in Frankel Grade following hematoma
evacuation (HE), those with time from onset of symptoms to (HE) < 6 hours had a mean improvement of 0.13 ,
those with time from onset of symptoms to (HE) of 6-12 hours had an improvement of 0.38, and those from 12-24
hours had an improvement of 0.22. Conversely, those with time from onset of symptoms to (HE) >24 hours had a
decline of -0.50.

Conclusions: The incidence of (POSEH) ranges from 0.1% to 3%. Neurologic recovery correlated with the time
from the onset of neurologic symptoms (HE). There was no significant difference in neurologic recovery if (HE}
was performed within 24 hours. However if (HE) was delayed beyond 24 hours, neurologic recovery was less likely
to occur.
Paper #33

Neural Complications of Surgery for Adolescent Idiopathic Scoliosis.

Mohammad Diab, MD (UCSF Medical Center); Timothy R. Kuklo, MD, JD

a - Medtronic Sofamor Danek

Introduction: We report on neural complications in a prospective cohort study of 1000 patients undergoing spinal
fusion and instrumentation for adolescent idiopathic scoliosis.

Methods: Records were reviewed of the first 1000 patients in the Prospective Pædiatric Scoliosis Study undertaken
by the Spinal Deformity Study Group.

Results: There were 9 neural complications. There were 4 cerebrospinal fluid leaks, one of which required dural
repair, and none of which demonstrated intraoperative neuromonitoring changes or had postoperative clinical
sequelæ. There were 3 nerve root injuries. In one, a positional compression femoral neurapraxia resolved over 6
weeks. The others were L4 neurapraxias despite lowest instrumented vertebra L1 and normal neuromonitoring; both
resolved spontaneously by 3 months follow-up. There were 2 spinal cord injuries. Common themes included > 70º
thoracic scoliosis, > 80% curve correction, normal intraoperative neuromonitoring, and imaging showing no implant
malposition. Both resolved spontaneously by 4 months after operation.

Conclusions: Our overall neural complication rate was 0.9%. If cerebrospinal fluid leak is eliminated, as it implies
intradural entry but not direct neural injury, our rate is 0.5%. Our findings are consistent with other studies in the
North American Literature, including multiple reports from the Scoliosis Research Society. The cases of spinal cord
injury appear to have been late onset secondary to spinal cord stretch after near total correction of large curves,
providing a cautious reminder of the power of modern instrumentation techniques. The L4 neurapraxias may also
represent a stretch phenomenon, as they were remote from the operative site. None of the neural injuries was
permanent. Our results reaffirm that surgical treatment of adolescent idiopathic scoliosis has a low neural
complication rate.
Paper #34

Infections Following Spinal Deformity Surgery: a Twenty-Year Assessment of 2876 Patients

Jacob Buchowski M.D., M.S.; Lawrence G. Lenke, MD; Craig A. Kuhns, MD; Ronald A. Lehman, Jr., MD;
Venkat Seshadri, MD (Washington University Medical Center); Brenda Sides, MA; Keith H. Bridwell, MD

Purpose: To evaluate post-operative infections in adult and pediatric patients undergoing spinal deformity surgery
at one institution over a twenty-year period (1985-2005) in order to determine risk factors, examine treatment
strategies, and analyze clinical outcome.

Materials and Methods: The medical records of 2876 adult and pediatric patients who underwent spinal deformity
surgery (≥5 levels) at one institution were analyzed. Patients who developed a wound infection requiring formal
debridement in the operating room were identified.

Results: Of the 2876 patients who were treated surgically for spinal deformity, 69 patients (41 females and 28
males) with an average age of 25.1±18.6 years developed a postoperative wound infection requiring a debridement
in the operating room, for an overall infection rate of 2.4%. Sixty-five patients (94.2%) had a posterior wound
infection and the remaining four patients (5.8%) had an anterior wound infection. The overall infection rate was
2.1% (39/1897) in pediatric patients (<18 years of age) and 3.1% (30/979) in adult patients (≥18 years of age). The
risk of developing a postoperative wound infection was in large part determined by the patient’s underlying
diagnosis as is illustrated in the table below. The average time from surgery until the infection was noted was
470±859 days (range, 4 days to 11.3 years). Patients were treated with irrigation and debridement and appropriate
antibiotics. Implants were not removed unless absolutely necessary. With appropriate treatment 39.1% of patients
(27/69) achieved solid fusion and only 26.1% (18/69) required removal of implants.

Conclusion: Post-operative wound infection can be a devastating complication; fortunately, however, the risk of
developing a post-operative wound infection following spinal deformity surgery is reasonably low (2.4%) and varies
considerably depending on the patient's underlying diagnosis. With appropriate treatment a large percentage of
patients can expect to achieve solid fusion and only a minority will require removal of implants.
Paper #35

Complications of Posterior Fusion and Instrumentation for Degenerative Lumbar Scoliosis

Kyu-Jung Cho MD, PhD (Inha University Hospital); Se-Il Suk, MD; Seung Rim Park, MD; Jin-Hyok Kim,
MD; Sung-Soo Kim, MD; Won-Kee Choi, MD; Kang-Yoon Lee, Jong-Min Lee

Purpose: To investigate the incidence and risk factors of complications in posterior fusion and instrumentation for
degenerative lumbar scoliosis

Methods: 47 patients (average age 66.6, range 48 to 83) of degenerative lumbar scoliosis undergoing posterior
instrumentation with a minimum 2-yr follow-up were analyzed. The average levels of fusion was 4.7±2.2 segments.
The upper instrumented vertebra was T10 in 10 patients, L1 in 6 patients, and L2 in 15 patients. The lower
instrumented vertebra was L5 in 22 patients, and sacrum in 24 patients. 7 patients had additional PLIF at the lower
lumbar spine. We evaluated the early perioperative (<3 mo after surgery) and late complications.

Results: The complications were more likely in older patients (>65 years) than younger patients (P=0.05). 28
patients had major co-morbidities including hypertension, diabetes and heart disease. The two or more co-
morbidities had the tendency to increase early complications with no statistical significance (P>0.05). Mean EBL
was 2106±1083ml. More than 2000ml of blood loss increased early complications with a statistical difference
(P=0.01). Operative time and fusion lengths were not associated with complications. There were 14 early
perioperative complications and 18 late complications. There was 1 mortality case by pulmonary embolism. Early
complications included G-I problems in 5 patients, postoperative delirium in 2 patients, superficial infection in 2
patients, and transient neurologic deficit in 1 patient. Late complications included 2 pseudarthrosis and 16 adjacent
segment diseases. Adjacent segment disease developed at proximal segment in 11 patients and at distal segment in 5
patients. Revision surgery was performed in 6 patients for pseudarthrosis and adjacent segment disease. (See Table)

Conclusion: The overall incidence of complications of posterior fusion and instrumentation for degenerative lumbar
scoliosis was 68%. Older age and abundant blood loss were risk factors for early perioperative complications.
However, there was no factor related with late complications.

                                        Table. Risk factors of complications
                                                  Early complications (n) Late complications (n)
                                                              2                    7
               Age (years)       ≤ 65 (n=17)               12 (P=0.05)           11 (P=0.77)
                                > 65 (n=30)
               Gender           M (n=8)                       1                    2
                                  F (n=39)                 13 (P=0.4)            16 (P=0.69)
               Smoking           Yes (n=6)                    1                    3
                                 No (n=41)                 13 (P=0.65)           15 (P=0.66)
               No. of co-morbidity 0 (n=20)                   8                    8
                                 1 (n=19)                     2                    6
                                 ≥2 (n=8)                   4 (P>0.05)            4 (P=0.65)
               Blood loss (ml)    ≤ 2000                      3                    9
               (n=24)                                      11 (P=0.01)            9 (P=0.91)
                               > 2000 (n=23)
               Op. time (min)     ≤ 200 (n=25)                5                     8
                               > 200 (n=22)                 9 (P=0.2)            10 (P=0.38)
               Fusion level      ≤ 4 (n=28)                   6                    11
                            > 4 (n=19)                      8 (P=0.19)            7 (P=0.87)
               Cobb angle (o)     ≤ 20 (n=27)                 7                    8
                                > 20 (n=20)                 7 (P=0.54)           10 (P=0.23)
               Lumbar lordosis (o) ≤ 30 (n=23)                7                     8
                                > 30 (n=24)                 7 (P=0.9)            10 (P=0.77)



Paper #36
Neurologic Complications of Pedicle Subtraction Osteotomy: a Ten-Year Assessment

Jacob Buchowski MD, MS (Washington University School of Medicine); Keith H. Bridwell, MD; Lawrence
G. Lenke, MD; Ronald A. Lehman, Jr., MD; Craig A. Kuhns, MD; Yongjung J. Kim, MD; David Stewart;
Christine Baldus, LPN

Purpose: To evaluate intra- and post-operative neurologic deficits following pedicle subtraction osteotomies (PSOs)
in order to determine risk factors, treatment strategies, and patient outcome.

Materials and Methods: A review of 110 consecutive patients (83 women and 27 men) with an average age of
54.7±13.9 years and treated with a PSO at one institution over a ten-year period (1995-2005) was performed.
Medical records, radiographs, and neuromonitoring data were analyzed.

Results: A total of 110 PSOs were performed. Following surgery, thoracic kyphosis increased from +28.2±18.6º to
+35.4±14.7º (p<0.012), lumbar lordosis increased from –16.3±19.5º to –50.2±15.2º (p<0.001), and sagittal balance
improved from +137±72mm to +21±52mm (p<0.001). Intra- and post-operative deficits (defined as motor loss of
two grades or more or loss of bowel/bladder control) were seen in twelve patients (10.9%). Deficits were found
intraoperatively during a wake-up test in three patients, immediately postoperatively in four patients, and in a
delayed manner in five patients. Intraoperative neuromonitoring did not detect the deficits. In eight patients
additional surgical intervention consisted of central enlargement and further decompression. Deficits were thought
to be due to a combination of subluxation, residual dorsal impingement, and dural buckling. They were always
unilateral, were never proximal to and usually did not correspond to the level of the osteotomy. Deficits ranged from
neurogenic bladder (one patient) to motor weakness of TA (seven patients), quadriceps (five patients), and EHL
(four patients) with four patients having weakness of multiple muscle groups. Three patients (2.7%) had permanent
deficits including weakness of TA (one patient), quadriceps (one patient), and both quadriceps/TA (one patient).
With time motor function improved by one grade in two patients and all three were able to ambulate.

Conclusion: Intra- or post-operative neurologic deficits are relatively common following a PSO, however, in a
majority of cases deficits are not likely to be permanent.
Paper #37

Iliac Venous Injury Complicating Anterior Spinal Surgery: Incidence, Predisposing Factors And
Management

Gary A. Fantini, MD (HSS/Cornell); Federico P. Girardi, MD; Ioannis P. Pappou, MD; Harvinder S. Sandhu,
MD; Frank Cammisa, Jr., MD

Background: Anterior spinal exposure at L4-L5 and L5-S1 levels is challenging, as the left common iliac vessels
course across portions of the disk spaces, making the left common iliac vein (CIV) is more prone to injury.

Purpose: To examine the incidence of major vascular injury during anterior spinal surgery, and to discuss the
management.

Methods: Ten major vascular injuries in 349 anterior spinal procedures by a single access surgeon were identified.
Operative reports and charts were reviewed.

Results: The incidence of major vascular injuries was 2.9%, with one aortic injury, nine CIV injuries (six left and
three right) and no deaths. Mean EBL was 1,410 ml. Predisposing factors were: scoliosis (2), osteomyelitis (2),
spondylolisthesis (2), osteophyte at L5-S1(1), revision ALIF (1), migrated PLIF cage (1). Initial control of bleeding
was obtained with spongestick compression, avoiding suction. Vascular clamps were not applied. Trendelenburg’s
position was utilized and definitive repair was attempted after preparations for volume resuscitation/ transfusion. In
eight venous cases, lateral venorrhaphy was performed, reinforced by topical hemostatic agents. In one venous case,
a 10 mm defect was repaired using vascular clips and fibrin glue. A single terminal aortal injury in the setting of
previous osteomyelitis and a bridging osteophyte occurred at L3-L4. Lateral aortorraphy with single figure-of-eight
suture was successful. Magnetic resonance venogram (MRV) was obtained in six patients with CIV injuries,
demonstrating venous patency in five - an IVC filter was placed in the latter patient.

Conclusion: Careful handling of the iliac vein and topical hemostatic agents can lead to successful outcome and
preserve venous patency. Spinal deformity, osteomyelitis, spondylolisthesis and osteophyte formation point to
increased risk of vascular injury. Postoperative screening for DVT with MRV and extremity venous duplex
scanning, is recommended in the setting of iliac vein repair.
Paper #38

Peri-Operative Complications in Revision Anterior Lumbar Spine Surgery: Incidence and Risk Factors

James D. Schwender, MD (Twin Cities Spine Center)

Introduction: Revision anterior exposure is often preferred to address pathologic lumbar spine conditions.
Significant risk of vascular and visceral injury results from scar tissue formation from the original surgical exposure.
Complication rates are anticipated to be greater than primary exposure. The objective was to determine occurrence
and risk factors of perioperative complications in revision anterior lumbar surgery.

Methods: 129 consecutive revision surgeries (1998 – 2003) in 108 patients (70% female; average age 50.6 years)
were retrospectively reviewed. Peri-operative complications were recorded. Revisions were either at the same
vertebral levels (pseudarthrosis; 70 surgeries) or at adjacent levels (59 surgeries). Original implants were most
commonly tricortical allograft (80%), cages in 8% and femoral ring allograft in 6%. Number of levels treated was
similar between groups (1-level 69%; 2-level 19%; three or more 12%). Revision cases were more commonly L4-L5
and/or L5-S1; extensions were more likely upper lumbar spine.

Results: Revision cases (same operative level) had a higher overall complication rate (42%) compared to extensions
(20%; p=0.007). Complications included: vein lacerations, ileus, peritoneal lacerations, infections. This difference
was primarily due to vein lacerations (23.7% vs 3.6%, p=0.002). There were no arterial tears; few dural tears (3.5%)
and one ureter injury (0.9%). The rate of peritoneal lacerations was similar between groups (Revisions: 22.0%;
Extension: 17.9%). There were no intraoperative deaths or permanent neurologic complications.

Revisions at same level were associated with longer operative time (p=0.004) and higher blood loss (p=0.003).
Blood loss greater than 1000cc occurred in 12% of extensions and 17% of revision cases (p>0.05).

Discussion: Complication rates for revision lumbar surgery in this series are three to five times higher than reported
non-revision lumbar exposures. Complication rates are significantly higher for revision anterior lumbar cases
compared to anterior extensions. All revision surgeries should be undertaken with proper planning and availability
of specialized co-surgeons.
                                          (Paper #38 attachment)

                                     Complication Rate by Revision Type
                                              Extension Revision    Total    P-value*
                    Any InterOp Comp            19.6%     42.4%     31.3%     0.007
                        DuralTear                7.1%      0.0%      3.5%      NS
                          Arterial               0.0%     0.0%       0.0%      NS
                           Vein                  3.6%     23.7%     13.9%     0.002
                          Ureter                 0.0%     1.7%       0.9%      NS
                        PeritonLac              17.9%     22.0%     20.0%      NS
                           Other                 3.6%     20.3%     12.2%     0.006
            •     Comparison between Extension and Revision
            •     NS: Not statistically significant, p>0.
            •     05.

                                Blood loss & OR Time by Revision Type
                        Extension             Revision               Total

                    Mean        Std.        Mean       Std.        Mean       Std.      p-value
                              Deviation              Deviation              Deviation
ORTime Anterior     129.36     59.726      152.05     59.200       141.00    60.282     0.043
 ORTime Total       295.21    130.798      336.05    128.175       316.17   130.509     0.094
 EBL Anterior       150.54    222.215      261.53    285.121       207.48   261.320     0.022
  EBL Total         616.52    942.608      745.51    775.437       682.70   859.527      NS
Paper #39

**Hibbs Award Nominee for Best Clinical Paper

Radiation Exposure during Pedicle Screw Placement in Adolescent Idiopathic Scoliosis: Is Fluoroscopy Safe?

Harry L. Shufflebarger, MD; Maahir Haque (Miami Children’s Hospital); Angel Macagno, MD; Michael
O'Brien, MD

Purpose: To determine radiation in scoliosis surgery.

Study design: A prospective, IRB approved study of AIS patients' surgery using fluoroscopically guided pedicle
screw placement.

Methods: Number of screws and fluoroscopy time were recorded. Thermoluminscent dosimeter (TLD)was used to
determine radiation dosage. Group 1 consisted of 14 patients with TLD worn outside lead protection, and the 6
patient group 2 had TLD worn inside thyroid shield.

Results: Group 1: 322 screws were placed with exposure time of 2347 seconds (7.4/screw). This resulted in a TLD
deep body dose of 152 mSv. Group 2: 122 screws were placed with a total of 629 seconds of exposure (5.2/screw).
This resulted in deep body dose of 13 mSv. Calculations were done to estimate the annual radiation exposure to the
surgeon, based 140 scoliosis surgeries. Group 1: the surgeon received 13.49 mSv radiation. Group 2: 4.31 mSv of
radiation.

Discussion: The dosages in both trial are not negligible. The International Commision on Radiological Protection
(ICRP) states that the maximum yearly dose limit for whole body exposure for classified workers (radiologist) is 20
mSv, and for the thyroid is 50 mSv. Non-classified workers (surgeons) are permitted only 30% of the classified
worker level of radiation exposure. This single year reccommendation does not consider lifetime accumulated
dosages. At the levels reported, a surgeon would surpass the recommended lifetime limits for non-classified workers
after less than 10 years exposure. It is unlikely he would surpass the limits for classified workers, 86 years.

Conclusions: Serious questions regarding radiation safety during scoliosis surgery are raised. Long term risks of
low level radiation are unknown. Acceptable levels of radiation are continually being revised downward.The
surgeon employing fluoroscopy for pedicle screw placement should use maximum protection and be treated as a
classified worker (radiologist), wearing a badge and having periodic examinations for radiation effects.
Paper #40

**Hibbs Award Nominee for Best Clinical Paper

SRS Surgeon Members’ Risk for Thyroid Cancer: Is it increased?

Theodore A. Wagner MD (University of Washington); Sue Min Lai, PhD; Marc A. Asher, MD

Introduction: In the past three years, three of our senior spine surgeons have been diagnosed with thyroid cancer,
raising concern about occupation related health risks for spine deformity surgeons. The purposes of this study are to
determine 1) whether there is an excess number of thyroid cancer diagnosed among SRS member surgeons and 2)
whether the information on exposure to radiation to the head and neck area would be available for further analyses
in exploring occupational risk for thyroid cancer. Our hypothesis was that head and neck cancer does relate to the
cumulative doses generated by C-arms and plain x-rays in operating rooms, or treatment areas. Only the first
question is explored.

Methods: With the support of the SRS Instrumentation Committee a survey of SRS member surgeons was
conducted.

Results: Eighty-one percent (528/650) of the SRS member surgeons responded to the survey. Due to the small
number of female surgeons (n=19) included in this survey, the results were based on responses for the SRS male
membership. The survey showed a total of 3 member surgeons who were diagnosed with thyroid cancers. In the
general age adjusted male population the expected number of thyroid cancer is 0.04 cases, suggesting a 25-fold
higher incidence of thyroid cancer in the SRS male surgeon membership. Other forms of cancers reported by this
cohort included prostate (n=12), melanoma (n=8), colon (n=4), and others (n=34).

Conclusions: This cohort of male members appears to have more than the expected number of thyroid cancers and
all cancers as well. Continued surveillance of background and worksite radiation exposure is warranted. In fact,
comparison to a control group of age and geographically adjusted male physicians and surgeons not routinely using
radiography the SRS surgeon incidence of thyroid cancer is being planned.

Précis: Eighty-one percent (528/650) of the SRS member surgeons responded to a questionnaire designed to
determine cancer prevelance and type. For male surgeons only, representing 81% of the cohort, there were 61
cancer (3 thyroid cancers). This cohort of male members appears to have a 25-fold higher incidence of thyroid
cancers than to the general male population.
Paper #41

Surgical Management of Cervical Kyphosis. A Long Term Follow-Up Study

Clayton L. Dean, MD (University Hospitals of Cleveland, Case Western); Michael H. Sun, MD; Henry H.
Bohlman, MD

Introduction: Symptomatic cervical kyphotic deformities represent a challenging problem for spine surgeons.
Treatment consists of decompression of neural elements and correction of sagittal alignment. The purpose of this
study was to report long term outcomes of patients treated surgically with cervical kyphosis.

Materials and Methods: Between 1985 and 2000, twenty-three patients were treated surgically for symptomatic
cervical kyphosis. Follow-up averaged 6.9 years (range, 2 to 17 years). Etiology included prior multilevel cervical
laminectomy (16), previous cervical trauma (2), post-radiotherapy myopathy (3), and cervical spondylosis (2). The
mean preoperative kyphosis was 45 degrees (range, 25 to 85 degrees). Ten patients complained of visual field
disturbances, twenty-two with neck pain, and four noted difficulty with swallowing. Twenty patients demonstrated
preoperative radiculopathy and/or myelopathy.

Results: Eleven patients were treated with anterior procedures alone, nine with combined anterior and posterior
procedures, and three with posterior procedures. Correction of sagittal alignment was accomplished through anterior
corpectomy (16), anterior and posterior cervical osteotomy (4), and posterior column shortening (3). Autogenous
iliac crest onlay graft was used for posterior arthrodesis, and iliac crest or fibular strut autograft was used for all
anterior arthrodesis. Significant neurological improvement (20/20) and correction of deformity (22/23) was noted in
long-term follow-up. Complications included graft dislodgement in three patients and strut graft collapse leading to
clinically significant loss of correction in one patient.

Conclusions: In patients with cervical kyphosis, anterior corpectomy and/or posterior cervical osteotomy through
the kyphotic segments provides adequate decompression of neural elements and restoration of sagittal alignment.
Anterior or posterior arthrodesis can be successfully achieved through a variety of surgical techniques. Patients with
a diagnosis of post-radiotherapy kyphosis represent a particular challenge and should be considered for combined
anterior and posterior procedures. The majority of complications arise from graft dislodgement or graft failure in
patients with poor bone quality.
Paper #42

Multilevel Fusion for Cervical Spondylosis: Is A Concomitant Posterior Approach Necessary?

Amir A. Mehbod, MD (Twin Cities Spine Center); Jonathan N. Sembrano, MD; Timothy Garvey, MD

Purpose: Retrospective clinical, radiographic, and outcome analysis comparing anterior-only (Ant) and
anteroposterior (AP) fusion for multilevel cervical spondylosis, to determine the effects of a concomitant posterior
approach in multilevel anterior fusion for cervical spondylosis in terms of operative parameters, fusion rates,
reoperation rates, and functional outcomes. Multilevel cervical fusion reportedly leads to dismal fusion rates. AP
fusion is considered a potential solution to this problem.

Methods: 78 patients (55 Ant, 23 AP) who had multilevel fusion for cervical spondylosis between 1998 and 2002
and with minimum 2-year follow-up were identified. Operative, inpatient, and outpatient data were reviewed.
Preoperative, postoperative, and follow-up imaging studies were analyzed. Between 2 and 6 years post-op, patients
were asked to answer functional outcome questionnaires (SF-36, Neck Disability Index [NDI], and Roland Morris).

Results: The Ant group incurred significantly less blood loss (165 vs 311 cc), shorter operative time (189 vs 380
min) and hospital stay (3 vs 4 days). In contrast, pseudarthrosis rates (38% vs 0%, p<0.001) and pseudarthrosis-
related reoperations (22% vs 0%, p=0.014) were both significantly reduced in the AP group. Nevertheless, no
significant difference in overall reoperation rates was shown (Ant 36.4% vs AP 30.4%). Both groups showed
improved lordosis post-op (Ant 8.6 vs AP 9.1 degrees), with no significant change over time (Ant 0.3 vs AP 1.6
degrees). Functional scores were similar for both groups using the SF-36 and NDI. However, using the Roland
Morris index, the Ant group showed a greater degree of functional impairment (Ant 8 vs AP 1.5, p=0.035).

Conclusions: A concomitant posterior fusion significantly reduces the incidence of pseudarthrosis and
pseudarthrosis-related reoperations compared to an anterior-only approach. However, no significant reduction in
overall reoperation rates was demonstrated. Functional outcome at 2 to 6 years may be better using Roland Morris
but is similar using the SF-36 and NDI.
                                        Cumulative Number of Reoperations Over Time
                                                 in Anterior and AP Groups.

                      100%




                       80%




                       60%

                                                                                              Ant
                                                                                              AP

                       40%




                       20%




                        0%
                                 <1mo            1-6 mos         6mos-1yr         >1yr
Paper #43

The Reliability and Concurrent Validity of the SRS-22r and CHQ-CF87 Patient Questionnaires for Spinal
Deformity Patients Ages 8 through 18 years

Douglas C. Burton MD; Marc A. Asher; Sue Min Lai, PhD; R. Christopher Glattes, MD (Kansas University
Medical Center); Elizabeth Fraser

Purpose: Spinal deformities are life long conditions that most often begin during the pre-adolescent years. A
questionnaire appropriate for evaluating health related quality of life (HRQL) throughout life is needed. The purpose
of this study is to determine the relative psychometric properties of the Scoliosis Research Society-22r (SRS-22r;
SRS) and Child Health Questionnaire-Child Self-Report Form 87 (CHQ-CF87; CHQ) questionnaires in spinal
deformity patients 8-18 years.

Methods: Seventy (58 females, 12 males) consented outpatients, mean age 14.1 years (+ 2.7; range 8-18), 51 with
idiopathic scoliosis and 19 with other spinal deformities completed a five domain SRS and a thirteen domain CHQ
HRQL. At an average of 24 days 54 patients returned, by mail, re-test questionnaires. Forty-eight of the seventy
patients had un-operated idiopathic scoliosis with the mean largest Cobb being 29.8º (±12.3º; range 10º - 66º).

Results: Ceiling effect averaged 26% (13-47%) for SRS and 37% (3-93%) for CHQ. Internal consistency (Cronbach
α) averaged 0.81 (range 0.72-0.93) for SRS and 0.81 (0.67-0.93) for CHQ. Test-retest intra class correlations (ICC's)
averaged 0.73 (0.56- 0.80) for SRS and 0.61 (0.20-0.85) for CHQ. Concurrent validity was r 0.70 or more for
relevant function, pain and mental health domains. The SRS self-image and satisfaction/dissatisfaction domains did
not correlate well with any CHQ domains. Findings were similar for the subgroup of 48 un-operated idiopathic
scoliosis patients.

Conclusion: The SRS-22r is reliable with internal consistency and reproducibility comparable to CHQ-CF87. SRS-
22r has a lower ceiling effect than CHQ-CF87 and the questionnaires are concurrently valid for relevant domains.
The SRS-22r is also valid in adults with spinal deformity and thus can be used for longitudinal assessment of health
related quality of life over the decades, measures self-image and management satisfaction/dissatisfaction, is shorter,
and can be easily hand scored.
Paper #44

The Role of Funding Source and Clinical Trial Outcome in Recent Orthopaedic Literature

Safdar N. Khan, MD (Hospital for Special Surgery); Matthew J. Mermer MD; Harvinder H. Sandhu, MD;
Elizabeth Myers

Introduction: The impact of the industry-scientist relationship on clinical trial outcome data is still being evaluated.
The purpose of the current study to evaluate the correlation between funding source and outcome in the recent
orthopaedic surgery literature.

Methods: Five major orthopedic journals were selected (Journal of Bone and Joint Surgery (Am), Spine, Journal of
Arthroplasty, Journal of Orthopaedic Trauma and American Journal of Sports Medicine) for inclusion. A two year
limit for investigation was chosen (2002-2004). All original randomized controlled clinical trials reported in these
five journals were included. Funding source was classified as follows: None; not-for-profit; mixed; industry and not
reported. Methodological and reporting quality was assessed with a modified Jadad score. Primary outcome was
based entirely on the authors’ interpretation of the outcome of the trial based on how the investigational group fared
against the controls. The categories included: Unclear; neutral; favored conventional treatment; favored new
treatment and rejected new treatment.

Results: Among 100 eligible orthopaedic clinical trials, support was stated as from industry in 26 trials (26%), not-
for-profit in 19 (19%), mixed in 5 (5%), and no support in 46 (46%). The type of support was not reported in 4% of
studies. In the 26 trials reporting support from industry, 22 (85%) were graded as indicating outcome favorable to
the new treatment. The association between industry funding and favorable outcome was strong and significant
(p<0.001). The unadjusted odds ratio was 11.6 (95% confidence interval: 3.1-42.5). The odds ratio showed little
change after adjustment for Jadad score (odds ratio = 10.9, 95% confidence interval: 2.6-44.7), indicating that the
quality of the trial did not affect the relationship between funding and outcome.

Conclusion: There appears to be a strong association between funding source and published clinical trial outcome in
the orthopaedic surgery literature.
Paper #45

**Hibbs Award Nominee for Best Clinical Paper

Risk Factors for Adjacent Segment Degeneration Following Lumbar/ Thoracolumbar Fusion with Pedicle
Screw Instrumentation: A Minimum 5 year Follow-up

Gene Cheh, MD (Washington University School of Medicine); Keith H. Bridwell, MD; Lawrence G. Lenke,
MD; Yongjung J. Kim, MD; Michael D. Daubs, MD; Jacob Buchowski, MD; Christine Baldus, LPN

Purpose: We had three hypotheses: 1) A longer fusion; 2) a more proximal instrumented vertebra and 3) a
circumferential fusion vs. a posterior-only fusion would increase the likelihood of adjacent segment degeneration
(ASD).

Methods: 181 patients with minimum 5 year follow-up who had single or multilevel lumbar/thoracolumbar fusion
with pedicle screw instrumentation for degenerative disorders (one institution 1985 to 2000) were included.
Radiographs were analyzed with regard to degeneration at the adjacent levels. Radiographic ASD was defined either
by: 1) development of spondylolisthesis >4mm; 2) segmental kyphosis >10 ; 3) complete collapse of disc space, or
4) more than 2 grade worsening in Weiner classification. Symptomatic ASD was defined as 1) symptomatic spinal
stenosis, 2) intractable back pain; or 3) sagittal or coronal imbalance.

Results: Average age of patients was 55 (range 26-81). Average follow-up was 7.9 years (range 5-16). Number of
levels fused were; 1-2 levels (n=133), 3-4 levels (n=29), and 5-8 levels (n=19). Radiographic ASD occurred in
44%(79/181) of patients, 56% (44/79) were symptomatic. Patients with radiographic ASD had worse Oswestry
scores (20.3 vs.12.5) (p=0.001). Symptomatic ASD manifested as spinal stenosis (n=43), instability-type back pain
(n=5), and sagittal or coronal imbalance (n=4). 8 of them didn’t show radiographic ASD. There was no significant
difference in age, follow-up period and postoperative lumbar lordosis between the patients who had symptomatic
ASD and who didn’t. Length of fusion, circumferential fusion vs. posterior-only and location of proximal
instrumented vertebra (PIV) were not significant factors in the development of ASD (Table).




                                                             Symptomatic          P
                                                                   ASD        value
                                                                +      -
                                          Age at surgery     58.4    54       0.255
                                         Follow-up years       8.1      7.8   0.307
                                Postop. Lumbar lordosis       -54°    -55°    0.873
                                    Fusion level      1         20      54
                                                      2         19      40    0.568
                                                    3-4         11      18    0.341
                                                     ≥5          2      17    0.224
                                               ASF/PSF          20      45
                                                      PSF       37      79        1
                                 PIV       distal thoracic       3      13
                                            upper lumbar        11      17    0.195
                                  Lumbar Lordosis <50°          11      21
                                                    ≥50°        16      47    0.471
                                  Age               <50°         9      41
                                                    ≥50°        43      88    0.066
Paper #46

Circumferential Fusion Improves Long-Term Outcome In Comparison To Instrumented Posterolateral
Fusion. A randomized clinical study with 5-9 years follow-up.

Tina Videbaek; Finn B. Christensen, MD, PhD; Rikke Soegaard; Ebbe Hansen; Kristian Høy, MD; Peter Helmig,
Bent Niedermann, Søren Eiskjær, MD; Prof. Cody Bünger, MD (Ortopaedic Research Lab.)

Introduction: Although lumbar spine fusion is a common used treatment in low back pain, controversy still exists
on the choice of surgical technique. Circumferential fusion has become a common surgical procedure. However, the
long-term claimed advantages of anterior lumbar interbody fusion (ALIF) plus posterolateral lumbar fusion (PLF)
over conventional PLF lack scientific documentation.

Aim: To analyze the effects of circumferential fusion on long-term outcome with respect to functional disability,
pain and general health.

Methods: From April 1996 through November 1999 a total of 148 patients with severe chronic low back pain were
randomly selected for either posterolateral lumbar fusion or circumferential fusion (ALIF plus PLF). The primary
outcome measure was the Dallas Pain Questionnaire (DPQ). The secondary outcome measures were the Oswestry
Disability Index, the SF-36 instrument and the Low Back Pain Rating Scale. All measures assessed the end-point
outcomes at 5-9-years postoperatively.

Results: The available response rate was 93%. The circumferential group showed a significantly better
improvement (p<0.05) in comparison to the posterolateral group with respect to all four DPQ categories: daily
activities, work/leisure, anxiety/depression and social interest. The Oswestry Disability Index and SF-36 (physical
health category) supported these results (p<0.01). The circumferential group experienced significantly less back pain
(p<0.05) in comparison to the posterolateral group.

Discussion: Circumferential lumbar fusion demands more extensive operative resources compared to posterolateral
lumbar fusion. However, 5-9 years after surgery the circumferentially fused patients had a significantly improved
outcome compared to those treated by means of PLF. These new results emphasize the superiority of circumferential
fusion in the complex pathology of the lumbar spine, and are strongly supported in all of the validated
questionnaires employed in the study.
Paper #47

Disc Height Reduction in Adjacent Segments and Clinical Outcome 10 years after Lumbar 360˚ - Fusion

Tobias L. Schulte, MD (University Hospital of Muenster), Freek Leistra; Viola Bullmann, MD; Thomas
Lerner, MD; Ulf Liljenqvist, MD; Lars Hackenberg; MD

Background: Adjacent segment degeneration is frequently discussed to impair long-term outcome after lumbar
interbody fusion. Nevertheless the amount and origin of degeneration and its clinical relevance remain unclear.

Material and Methods: Forty patients (degenerative disc disease, n = 27; lytic spondylolisthesis, n = 13) underwent
lumbar 360 fusion and instrumentation. Preoperative and follow-up lateral radiographs of the lumbar spine were
studied. Disc heights of first and second cephalad adjacent segments were measured by Farfan’s and Hurxthal’s
technique modified by Pope. Clinical outcome was studied using Oswestry Disability Index (ODI) and Visual
Analogue Scale (VAS). Age, gender, prior surgery, fusion rate and number of fusion levels were investigated as
potential factors affecting the outcome.

Results: Mean follow-up was 114 months. Clinical outcome showed an improvement of 44.6% in ODI and of
43.8% in VAS with a tendency towards better clinical results in group 2. Fusion rate was 95%. Disc height of the
first cephalad adjacent segment in all patients was significantly reduced by an average of 21% (Farfan) respectively
19% (Pope), that of the second adjacent level by an average of 16% (Farfan) respectively 14% (Pope). A tendency
towards a more explicit disc height reduction in the degenerative group was observed. Advanced age significantly
correlated with advanced disc height reduction. Multiple level fusion led to a more pronounced disc height reduction
than single level fusion. Gender, prior surgery of the fused segment and fusion level did not affect the amount of
disc height reduction. There was no correlation between the clinical outcome (VAS; Oswestry) and the amount of
disc space narrowing.

Conclusion: Lumbar fusion is associated with disc height reduction of adjacent discs. This may be induced by
additional biomechanical stress, ongoing degeneration affecting the lumbar spine and advancing age. Clinical
outcome is not correlated with adjacent disc space narrowing.
Paper #48

Gravity Line and Spino-Pelvic Parameters: Age Related Changes Among Asymptomatic Adult Volunteers.

Virginie Lafage, PhD (Maimonides Medical Center); Frank J. Schwab, MD; Reid Boyce, MD; Francisco
Rubio; Wafa Skalli, MD; Jean-Pierre C. Farcy, MD

a - Medtronic Sofamor Danek

Introduction: Although work by several authors has placed emphasis on global balance in the setting of spinal
deformity, the relationship of spino-pelvic parameters related to this concept remains poorly defined. Using the force
plate device and radiographic measurement, this study aimed to define the relationship between these parameters
and the location of the gravity line (GL) in asymptomatic adult population.

Materials and Methods: 75 asymptomatic adult volunteers were recruited and subdivided by age (18-40, 41-60,
>61). Full-length free-standing AP and lateral radiographs were obtained with simultaneous assessment of the force
plate gravity line (GL) location. The latter was projected on each x-ray to compute distance between anatomical
components and GL and correlate its location with radiological parameters. Age related changes were investigated
using ANOVA with Bonferroni-Dunn Post-Hoc test.

Results: Radiographic measurements revealed strong correlations between trunk global inclination and distance
from S1 to the GL (r=0.7), sacral slope and pelvic incidence (r=0.78), distance from the bi-femoral head axis to the
GL and S1 to the GL (r=0.73), and sacral slope and lordosis (r=0.89). With advancing age, the GL location with
respect to the heels does not change and a global spino-pelvic regulatory mechanism appears to maintain this
posture: trunk global inclination shifts forward, pelvic tilt increases, and the pelvis shifts toward the heels, increasing
its distance from the GL.

Discussion: This study demonstrates the importance of pelvic parameters and trunk inclination in the regulation of
the GL location. The relationship between the gravity line, pelvic parameters, and overall spinal alignment may
emerge as essential in the evaluation of spinal deformity. Further investigation in this field may lead to a formula of
balance that can assist in optimal planning of corrective procedures for spinal deformity.
Paper #49

Laminectomy in Patients with Achondroplasia: the Impact of Time to Surgery on Long-Term Function

Joshua G. Schkrohowsky, BS; Emily Carlisle, MA; Richard L. Skolasky, Jr., MA; Daniele Rigamonti, MD;
Michael C. Ain, MD (Johns Hopkins University)

Backgound: Spinal stenosis is common among patients with achondroplasia. Laminectomy can relieve symptoms
of spinal stenosis and prevent permanent nerve damage. Our study has determined how the length of time between
symptom onset and laminectomy affects the functional outcome in patients with achondroplasia

Methods: We performed a retrospective study of sixty-one patients with achondroplasia who underwent
laminectomy for spinal stenosis at our institution. Patients completed a questionnaire to assess symptoms, walking
distance, and independence (assessed via Modified Rankin Scale), preoperatively and currently. Responses were
analyzed for the impact of time to surgery on the likelihood of experiencing improved walking distance or Rankin
level at the time of the survey.

Results: Patients with a time-to-surgery interval of less than six months were 6.22 times (95% confidence interval,
1.54 to 25.15) more likely to experience improvement in walking distance and 3.6 times (95% confidence interval,
1.03 to 12.54) more likely to experience improvement in Rankin level than patients whose time-to-surgery interval
was more than six months. Intervals of up to twelve and eighteen months were associated with increased likelihoods
of 5.14 (95% confidence interval, 1.69 to 15.69) and 4.41 (95% confidence interval, 1.46 to 12.78), respectively, of
improved walking distance compared with those with longer time-to surgery intervals, but improvement in Rankin
level was not significant for those times. Surgery after an interval of up to twenty-four months did not result in
significant improvement based on either type of assessment.

Conclusions: The interval from onset of symptoms to surgery in achondroplastic patients is an important predictor
of long-term functional outcome. For the surgery to provide sustained long-term improvement, the window of
opportunity might be relatively narrow. Patients with achondroplasia should be urged to seek medical advice for
spinal stenotic symptoms as soon as possible.
Paper #50

Transforaminal Lumbar Interbody Fusion with rhBMP-2 and Allograft: Two-Year Prospective Clinical
Evaluation of a Surgical Strategy

Milan Mody, MD (Spine Research Foundation); Keri B. Warren; Rex A. W. Marco, MD; Ramin Raizadeh;
Vivek Kushwaha

a - DePuy AcroMed

Purpose: To assess outcomes of patients treated with one- or two-level posterior instrumented TLIF augmented
with allograft and rhBMP-2 for the treatment of symptomatic spondylolisthesis or degenerative disk disease.

Methods: During a consecutive 13-month period, 77 patients with lumbosacral degenerative and deformity
conditions underwent TLIF procedures augmented using rhBMP-2 with simultaneous posterolateral fusions with
allograft. Pedicle screw instrumention provided distraction and a carbon-fiber curvilinear cage packed with rhBMP-
2 was placed into the disk space after hemifacetectomy and diskectomy. Patients were followed at 2 weeks and 3, 6,
12, and 24 months after surgery with functional parameters including the visual analog scale (VAS), SF-36 and
Oswestry Disability Index (ODI) questionnaires. Follow-up assessments were compared with preoperative values,
and fusion was assessed radiographically at the prescribed intervals.

Results: A fusion rate of 94% was achieved with only four pseudarthroses. At 24 months, 85% and 81% of patients
improved upon preoperative ODI and SF-36 measures, respectively, while 70% of patients had good to excellent
outcomes by both measures. There was one wound infection treated with hardware removal and intravenous
antibiotics. One patient had excessive bone growth into the foramen, necessitating surgical decompression with
subsequent excellent clinical outcome. Ten patients experienced TLIF-side paresthesias, all of which resolved by
three weeks.

Conclusions: The use of rhBMP-2, in combination with posterolateral allograft, can provide a high fusion rate and
good clinical outcomes in a TLIF setting. The morbidity associated with iliac crest bone graft is avoided, with fusion
rates approaching that of a true anterior/posterior circumferential fusion. The cage with rhBMP-2 must be placed
anteriorly enough to avoid overgrowth of bone into the neural foramen, likely related to rhBMP-2 residue at the
TLIF entry site. Complications were few, with no significant neurologic sequelae from placing a structural graft into
the anterior column through a posterior approach.


** The FDA has not cleared a drug and/or medical device described in this presentation (i.e., the drug or medical
device is being discussed in an (off-label use.) For full information refer to page 5
Paper #51

Free Hand Pedicle Screw Placement during Revision Spinal Surgery: Analysis of 552 Screws

Young-Woo Kim, MD (Washington University School of Medicine); Lawrence G. Lenke, MD; Yongjung J.
Kim, MD; Keith H. Bridwell, MD; Youngbae B. Kim, MD

a - Medtronic Sofamor Danek
d - Medtronic Sofamor Danek
e - Medtronic Sofamor Danek

Purpose: Placement of pedicle screws into previous fusion masses or pseudarthrosis levels of the spine is
challenging because of the loss of normal anatomic landmarks. The purpose of this study is to evaluate the safety of
free hand pedicle screw placement at levels with a solid posterior fusion mass as well as at levels of identified
pseudarthrosis of the thoracic and lumbosacral spine without any fluoroscopic or image-guided assistance.

Methods: (See table) Thirty-seven patients underwent revision spinal surgery with posterior spinal instrumentation
and fusion utilizing 552 transpedicular screws by a single surgeon from 1994 to 2003. Among 552 screws, 308
screws placed into fusion masses (208 screws) and pseudarthrosis levels (100 screws) were analyzed using
radiographs, intraoperative monitoring data, and clinical outcomes. We used the quadrangulation method to find
pedicle access in a prior fusion mass using any visible anatomic landmarks. Following screw placement,
electrophysiologic (triggered EMG) and radiographic confirmation was performed intraoperatively.

Results: The mean age at the time of surgery was 38+6 years (range 8-75). Four screws were removed
intraoperatively according to low triggered EMG criteria and three of them were repositioned (4 out of 308 total
screws, 1.30%). Two patients were revised at postoperative day 3 and 6 weeks respectively for root decompression
at the osteotomy site but the screw positions were correct. Two patients complained of transient weakness with foot-
extension but improved spontaneously in 2 weeks (neurologic complications: 4/37 patients, 10.8%). There were no
neurologic, vascular, or visceral complications with screw placement.

Conclusion: The free hand technique of thoracic and lumbosacral pedicle screw placement in revision spinal
surgery is a reliable and safe method of insertion when using the quadrangulation method of gaining pedicle access
through a prior fusion mass or at pseudarthrosis levels.
Paper #52

Randomized Clinical Study to Compare the Accuracy of Navigated and Non-Navigated Thoracic Pedicle
Screws in Deformity Correction Surgeries.

S Rajasekaran, MS, DNB, FRCS, MCh, PhD (Ganga Hospital); Ajoy P. Shetty; Vidyadhara S; Ramesh
Perumal

Study Design: Randomized clinical trial (Level I evidence).
Summary of the background data: Iso-C based navigation has improved the accuracy of spine navigation and has
relevance to deformity correction surgery as data acquisition can be performed after positioning and exposure. But
its efficacy in thoracic deformity correction surgeries has not been reported in the literature.

Methods: Thirty three patients (27 scoliosis and 6 kyphosis) were randomly allocated to navigation group (17
patients and 242 screws) and non-navigation group (16 patients and 236 screws). Cobb’s angle was 58.4 ±8 (range
50 -80 ) and kyphotic angle was 54.6 ±4 (range 51 -76 ). Accuracy was analysed on post-operative CT scans by two
independent observers blinded to the study.

Results: The non-navigation group had an average of 5.2±2.8 (3-13) exposures per screw taking about
4.61±1.05min (1.8-6.5min) per screw. The C-arm had to be moved in to the operation field at an average of 4±3 (1-
11) times per screw. The navigation group had an average insertion time (including average data acquisition time
per screw) of 2.37±0.72min per screw (range 1.16-4.5 min). The average data acquisition time in the ten patients
was 24.6±6.3min (range 16-33 min). There were fifty four (23%) pedicle breaches in the non-navigation group as
compared to only five (2%) in the navigation group and this was statistically significant (p<0.001). Mid-thoracic
region had the highest rate of pedicle breaches (49%). Thirty eight screws (16%) in the non-navigation group had
penetrated the anterior or lateral cortex compared to two screws (0.8%) in the navigation group. There were higher
pedicle breaches noticed in kyphosis (27%) compared to scoliosis (11%).

Conclusions: Iso-C based navigation surgery in thoracic deformity correction surgeries using pedicle screw
instrumentation reduces surgical time, radiation exposure time, decreases pedicle perforations, increases depth
perception, enhances accuracy, and also the surgeon’s confidence to a large extent.
Paper #53

Computed Tomography (CT) Evaluation of Pedicle Screws Placed into Deformed Spines over an 8 year
Period

Ronald A. Lehman, Jr. MD; Lawrence G. Lenke, MD; Yongjung H. Kim, MD; Gene Cheh, MD; Kathryn
Keeler, MD; Brenda Sides, MA

Objective: To evaluate the incremental accuracy of pedicle screws used in spinal deformity via a free-hand-
technique at a single institution over an 8-year period.

Background: The in vivo accuracy of free-hand pedicle screws placed throughout the deformed spine as evaluated
by CT scanning is unknown over a long time-period.

Materials/Methods: A total of 1023 pedicle screws in 60-patients (927 screws for 54-scoliosis patients and 95-
screws for 6-kyphosis patients) inserted between T1-L4 during an 8-year period were investigated with
postoperative CT scans. Patients were divided into 3 groups (Group-I=1998-2000,Group-II=2001-2003 and Group-
III=2004-2005). All pedicle screws were inserted using the free hand technique using anatomic landmarks, specific
entry sites, neurophysiologic, and radiographic confirmation. The position of the pedicle screw by CT scan was
graded as an acceptable screw versus violated screw(with significant violation), defined as the axis of the screw
being outside the cortex of the pedicle wall.

Results: 03/1023 pedicle screws (9.8%) demonstrated significant mediolateral pedicle wall violations (19-medial vs.
84-lateral,p=0.001). Group-I and III had significantly higher lateral wall violations than Group-II(p<0.05) as did the
kyphotic spines(vs. scoliotic spine,p<0.05). There were significantly more screws placed in the periapical region
over time (p<0.0001), with left-sided lateral violations (T5-8) increasing from Group-II to Group-III, while the
number of medial violations significantly decreased with time (p<0.0001). Also, pedicle screws placed on the right
side showed a significant decrease in accuracy from Group-II to Group-III (p=0.03). The average transverse angle of
the acceptable screws was 15.3° and was significantly different from that with either medial (23.0°,p<0.001) or
lateral(10.6°,p<0.001) violations between Group-I and Group-II. No screws with significant violation demonstrated
neurologic, vascular, or visceral complications.

Conclusions: The overall accuracy of acceptable screws using the free-hand pedicle screw placement technique in
the deformed spine was 91.2% without any neurologic, vascular, or visceral complications over an 8-year period.
The rate of medial violations decreased with time, as the number of periapical region increased.
Paper #54

Retrieval of Charité Disc Prosthesis. Experience in 15 patients

Andre Van Ooij, MD (University Hospital of Maastricht); Lodweijk W. Van Rhijn, MD, PhD; Steven S. Kurtz,
PhD

a - Medtronic Sofamor Danek

Out of a series of 67 patients with persistent leg- and backpain after insertion of Charité disc prostheses we removed
in 15 patients 18 prostheses and performed an anterior and posterior fusion. The indication for removal was our and
the patients dissatisfaction after performing only posterior fusion in another series of 16 patients. The causes of
persisting pain were subsidence, migration, wear, facetjoint degeneration and adjacent degeneration in various
combinations. 10 patients were female, 5 male. Mean age at retrieval was 48 years (40-60 years) and time interval
between insertion and retrieval was 9 years (range 3-16 years). Mean bloodloss for the anterior procedure was 541
cc (150-5100 cc). Intraoperatively we encountered 2 times a lesion of the vena iliaca communis and once a lesion of
the arteria iliaca communis, that could be controlled by the vascular surgeon. In all patients polyethylene wear of the
core was seen in various degrees with surrounding PE particles containing inflammatory fibrous tissue. The clinical
results are diverse. Short segment fusions have a far better prognosis than long segment fusions or flexible fixations
performed due to multilevel degeneration. This series shows, that removal of Charité artificial discs is feasible but
with its inherent risks and that wear of the polyethylene core will be a major issue after moderate to long-term
follow-up after Charité disc replacement surgery
Paper #55

Cervical Disk Replacement in Adjacent Segment Disease— 2 Year Follow Up Of 51 Cases

Paul C. McAfee, MD; Luiz Pimenta, MD, PhD; Matthew Scott-Young, MD; Alan Crockard, MD; Andrew
Cappuccino, MD

a – Cervitech; De Puy Spine
b – Cervitech; De Puy Spine
c – Cervitech; De Puy Spine
d – Cervitech; De Puy Spine
e - Cervitech; De Puy Spine

Purpose: Prospective consecutive series of 51 prosthetic implantations with over 95 % follow up at two years post-
operatively-- Class II Levels of Evidience.

Methods: This is a prospective consecutive study of 51 PCM prostheses inserted in forty-one patients with 60
adjacent segments previously fused or rendered immobile—ten cases were performed as bilevel implantations. The
inclusion and exclusion criteria were otherwise identical to the normal FDA prospective IDE criteria with all
patients presenting with radiculopathy and a corresponding neurologic deficit confirmed by an MRI compressive
lesion.

Results: The mean preoperative cervical lordosis was 2.65 degrees (-32 to 25), mean postoperative lordosis 12.3
degrees (-17 to 30), and the mean improvement was 9.4 degrees of cervical lordosis (range (-15 to 23). EBL = 0 to
100 cc with no patients requiring blood transfusions, Length of surgery = mean 104 minutes (60 to 150) and the
length of hospital stay = mean 1.17 days (0 to 3 days). All patients were neurologically intact at follow up with a
mean improvement of NDI = 50 % and mean improvement in VAS = 58.3 %. The range of flexion and extension
motion at the level of the prosthesis was a mean of 8.9 degrees (range 4 to 20 degrees).

Conclusions: Adjacent levels are a chalenging environment for cervical disk arthroplasty--19 of the 60 previously
fused levels had prior cervical instrumentation. 5 patients had previous cervical cages, 2 had cage-plates, 7 patients
had previous anterior cervical plates, one had a prior arthroplasty device with HO, and 4 patients had PMMA which
required revision. An added potential bonus is the preserved 8.9 degrees of flexion – extension mobility. The PCM
appeared to work well in these revision cases. This is the largest study to date investigating prospectively the value
of cervical arthroplasty at vertebral levels adjacent to an anterior cervical fusion.
Paper #56

Comparison of Radiographic Outcomes for Scoliosis Curves ≥100 degrees: Wires vs Hooks vs Screws

Kei Watanabe, MD; Lawrence G. Lenke, MD; Keith H. Bridwell, MD; Yongjung H. Kim, MD; Kota Watanabe,
MD; Marsha Hensley, MD; Georgia Stobbs

A - Medtronic Sofamor Danek
D - Medtronic Sofamor Danek
E - Medtronic Sofamor Danek

Purpose: Spinal fusion in scoliosis curves greater than 100 degrees are challenging surgeries, because of a high rate
of complications including pseudarthrosis, instrumentation failure, and neurologic issues. Our purpose was to
compare the radiographic outcomes by different techniques and anchors in the surgical treatment of scoliosis greater
than 100 degrees.

Methods: 60 patients (21 idiopathic, four congenital and 36 neuromuscular) with greater than 100 degree curves
(range; 100-158º) who underwent spinal fusion with different techniques and anchors on the apical levels, were
include for analysis. All patients had a minimum 2-year follow-up (mean, 4.2 years; range 2.0-10.5 years) and were
classified into Group W (wires, n=25), Group H (hooks, n=18), Group A (anterior vertebral screws, n=6), and Group
PS (pedicle screws, n=11), based on the type of apical anchor utilized.

Results: (See Table) There were no statistically significant differences between the groups for gender, age, number
of levels fused, and preoperative main curve Cobb angle. Curve flexibility using stress x-rays in the H group was
significantly smaller than in the W group (p<0.05). The PS group showed significantly greater amount of correction
than the other groups (p<0.0001) and smaller correction loss than the W group (p<0.05) at final follow-up. There
were four cases of pseudarthrosis (W group: 3, H group: 1), seven cases of implant failure including rod breakage or
hook pull-off (W group: 5, H group: 2), and 12 cases of radiolucency surrounding the lowest implant (W group: 9, A
group: 2, PS group: 1). Although there were four neurological complications (3 degraded spinal cord monitoring, 1
failed wake-up test), there were no permanent neurological deficits.

Conclusions: Apical pedicle screw constructs are able to achieve and maintain better correction without
instrumentation failure compared to other instrumentation constructs in scoliosis curves of greater than 100 degrees.
                                                 (Paper #56 attachment)

   Table: Radiographic data
                              Group W                                                    Group PS          Significance
                                                 Group H (n=18)       Group A (n=6)
                              (n=25)                                                      (n=11)            (ANOVA)
Age at Surgery (years)            13.6±3.9          19.4±13.7           15.8±1.2         15.6±5.5            p=0.1691
                                  A/P: 17            A/P: 17                              A/P: 6
Surgical Approach                                                         A/P: 6
                                   Post: 8           Post: 1                              Post: 5
Main Curve Cobb
                                113.9±14.7         109.4±12.7*          107.2±9.4       121.1±19.6*          p=0.1402
Preoperatively
Stress x-ray
                                37.5±17.9*          23.3±12.0*          37.0±16.6        31.1±18.3           p=0.0619
Flexibility (%)
Main Curve Cobb
                                53.5±18.4*         73.3±21.8*†‡         42.4±11.6†      45.4±23.0‡           p<0.001
Postoperatively
                                                                 †‡                 †               ‡
Correction Rate (%)             52.7±16.0*         32.9±18.7*           60.5±9.7        62.5±17.4            p<0.0001
Amount of Correction                         †              †‡                     ‡                †‡
                                58.9±20.6*         35.6±20.8 **       64.7±10.1 **      75.7±26.0*           p<0.0001
Postoperatively
Amount of
                                 8.4±7.6*            7.2±11.7             4.5±6.8        1.9±3.0*            p=0.1892
Correction Loss
Pelvic Obliquity
                                28.7±26.6*†          5.2±4.0*           20.6±15.8       15.4±12.9†            p<0.01
Preoperatively
Pelvic Obliquity
                                 9.8±8.3*            4.5±3.7*           10.4±6.8          6.1±4.1            p=0.0667
Postoperatively
C7 Translation
                               137.8±100.6*        18.0±12.6*†‡        100.0±91.0†      89.4±94.6‡           p<0.001
Preoperatively
C7 Translation
                                66.1±57.1*          18.1±11.3*†         68.3±67.4†       34.8±32.4            p<0.01
Postoperatively
Clavicle-Angle
                                13.8±9.1*†           4.5±3.2*             5.6±3.0†        9.2±6.8            p<0.005
Postoperatively
Clavicle-Angle
                                 4.7±3.6*            4.3±2.4              3.6±3.6        2.4±1.9*            p=0.2191
Postoperatively
                                                                                        Fisher’s PLSD: p<0.05 * † ‡
Paper #57

Impact of Sagittal Plane Spinal Deformity on the Spino-Pelvic Relationship and Gravity Line Position in
Adults

Virginie Lafage, PhD; Frank J. Schwab, MD; Francisco Rubio; Jean-Pierre C. Farcy, MD

a - Medtronic Sofamor Danek

Introduction: Sagittal spinal imbalance in the adult remains poorly understood and challenging. Limitations of
radiographic analysis have lead researchers to apply forceplate technology to enhance the study of spinal balance
through evaluation of the gravity line (GL). The aim of this study was to investigate differences between
asymptomatic adults and patients with sagittal spinal deformities, with a hypothesis that imbalance would lead to
changes in the GL – spinal relationship.

Material and Method: This prospective study included 44 asymptomatic subjects (mean 57yo) and 40 patients with
sagittal deformities (mean 65yo, inclusion criteria: L1-S1 lordosis<25 , Pelvic Tilt>20 , C7 plumbline>5 cm).
Coronal plane deformities were excluded. Full-length free-standing sagittal radiographs were obtained with
simultaneous acquisition of the GL and heel position (by forceplate). Spino-pelvic radiographic parameters were
calculated and distances (offsets) from the GL analyzed. Group differences were evaluated by independent sample t-
tests.

Results: Groups did not differ in age, thoracic kyphosis, offsets from femoral heads to heels, femoral heads to GL,
and GL to heels. As per inclusion criteria the sagittal deformity group had greater mean C7 plumbline (8cm vs 0cm),
increased pelvic tilt (27 vs 13 ) and loss of lordosis (46 vs 58 ). The sagittal deformity group also had greater pelvic
incidence (60 vs 51 ), anterior trunk inclination (-3 vs -11 ), S1 displacement toward the heels (distance decreased,
87 vs. 46mm). All differences p<0.001.

Discussion: The sagittal spinal deformity group revealed marked differences; the sacrum has a more posterior
position in relation to the GL and heels. However, the GL to femoral head offset was not markedly influenced. The
additional finding of no change in the GL to heel offset and rather fixed GL-femoral head offset appears to indicate
that sagittal spinal deformity induces a posterior sacral translation and pelvic retroversion in order to maintain a
fixed GL-heel relationship.
Paper #58

Decompression Alone vs. Decompression with Limited Fusion for the Treatment of Degenerative Lumbar
Scoliosis with Stenosis

Gene Cheh, MD; Lawrence G. Lenke, MD; Keith H. Bridwell, MD; Yongjung J. Kim, MD; Michael D. Daubs,
MD; Georgia Stobbs

a - Medtronic Sofamor Danek
d - Medtronic Sofamor Danek
e - Medtronic Sofamor Danek

Purpose: To analyze clinical results between decompression alone and decompression with limited fusion for the
treatment of degenerative lumbar scoliosis (DLS) with stenosis.

Methods: 54 patients who underwent decompression alone (n=16) or decompression with instrumented fusion of
one or two levels (n=38) were analyzed. Clinical results graded by length of initial good result until recurrence and
patients’ self-reported satisfaction were compared at 2 years postoperative. Excellent grading was given when
symptom-relief persisted more than 2 years postoperative. Radiographs were evaluated relative to curve progression
and adjacent segment breakdown.

Results: (See Table) Average follow-up was 4.9 years in the decompression group vs. 5.3 years in the fusion group
(p=0.593). Average age at surgery was 74 years (range 64-87) in the decompression group and 65.7 (range 44-79) in
the fusion group (p=0.002). At 2 years postoperative, clinical satisfactory results (good to excellent) were found in
10 out of 16 (62%) decompression patients vs. 33 out of 38 (87%) fusion patients (p=0.06). At 5 years
postoperative, 37% (3/8) of the decompression group were symptom-free compared with 63% (12/19) of the fusion
group (p=0.398). In the decompression group, 12 out of 16 patients developed recurrence of spinal stenosis at the
previous decompression site and five recurred within six months postoperative. In fusion group, 13 out of 38
patients had recurrent stenosis at an adjacent segment (p=0.01) (table). Radiographic adjacent segment degeneration
was observed in 45% (17/38) of patients who had limited fusion, eight (47%) of which had symptomatic spinal
stenosis.

Conclusion: Recurrence of stenosis after very short-term symptom-relief was common following decompression
alone. Adjacent segment breakdown was common in the fusion group, but less than half had associated stenosis.
Because transition syndrome was less problematic than postoperative instability, limited fusion appears to be a
better strategy than decompression alone for the treatment of DLS with stenosis.


     Recurrent Spinal Stenosis        Decompression Alone Group (n=15)          Limited Fusion Group (n=39)
                 Within 6 months                      5                                       0
                       0.5-2 years                    1                                       2
                         2-5 years                    4                                       6
                    After 5 years                     2                                       5
                                                     12                                      13
Paper #59

Comparison of Short Fusion versus Long Fusion for Degenerative Lumbar Scoliosis

Kyu-Jung Cho MD, PhD; Se-Il Suk, MD; Seung Rim Park, MD; Jin-Hyok Kim, MD; Sung-Soo Kim, MD;
Kang-Yoon Lee, MD; Jeong-Joon Lee, MD; Jong-Min Lee, MD

Purpose: To compare the results of short fusion and instrumentation versus long fusion and instrumentation for the
treatment of degenerative lumbar scoliosis.

Methods: Forty-seven patients undergoing short fusion (n=28) and long fusion and instrumentation (n=19) were
evaluated with a minimum 2-yr follow up. Short fusion was defined as the fusion within scoliotic deformity, and
long fusion as the fusion up to more proximal segment to upper end vertebra. The upper end vertebra was L1 in 22
patients and L2 in 15 patients. The fusion level was 3.14±0.97 segments in short fusion and 6.89±1.29 in long
fusion. Patients’ age and number of co-morbidities were similar in both groups. (See Table)

Results: Before surgery, the scoliotic angle was 16.3o (range 11-28) in short fusion and 22o (range 12-33) in long
fusion. The correction of the curve was better in long fusion than short fusion (P=0.001). Mean EBL was more
abundant in long fusion (2742ml±1315) than in short fusion (1671ml±604.8) (P=0.001). Operative time (179 min vs
224 min, P=0.009) and hospital stay (18.4 day vs 24.2 day, P=0.008) was longer in long fusion group. There were
substantial complications in both groups, 15 of 28 short fusion and 17 of 19 long fusion. Pseudarthrosis was noted in
2 patients of long fusion, whereas no pseudarthrosis in short fusion group. There were 10 adjacent segment disease
in short fusion, whereas 6 adjacent segment disease in long fusion group. The improvement of Oswestry score was
similar in both groups (P=0.137).

Conclusion: The long fusion and instrumentation for degenerative lumbar scoliosis was better to correct the
scoliotic deformity than short fusion, but demonstrated more blood loss and longer hospital stay. The early
perioperative and late complications developed at similar rate in both groups. The Oswestry score at the last visit
was identical in both groups.


                                 Short Fusion (n=28)        Long Fusion (n=19)           P-value
Fusion level (n)                      3.14 ± 0.97               6.89 ± 1.29              <0.001
Age (year)                            64.4 ± 8.1                68.7 ± 5.8                0.192
No. of co-morbidities                  1.75 ± 0.8                1.74 ± 0.7               0.974
Blood loss (ml)                     1671.4 ± 604.8             2742.1 ± 1315              0.001
Op. time (min)                       179. 1 ± 56.9              224.5 ± 57.1              0.009
Hospital stay (day)                    18.4 ± 8.3               24.2 ± 10.5               0.008
Cobb angle (o)
     Preop                             16.3 ± 4.7                 22.0 ± 6.3              0.002
     Final                             10.1 ± 5.4                 8.47 ± 6.4              0.287
     Change                            6.25 ± 3.4                 13.5 ± 8.5              0.001
Lumbar lordosis (o)
     Preop                            32.7 ± 109                  27.6 ± 13.5              0.2
     Final                            31.6 ± 12.3                 23.6 ± 11.3             0.07
     Change                            10.7 ± 8.7                  4.0 ± 8.6              0.233
Oswestry score
     Preop                            62.3 ± 20.4                 52.0 ± 12.4             0.123
     Final                            47.4 ± 27.6                 32.7 ± 17.1             0.081
     Change                           14.8 ± 12.5                  19.3 ± 8.3             0.137
Early complications                    5 (17.9%)                   9 (47.4%)              0.195
Late complications                    10 (35.7%)                   8 (42.1%)              0.763
Paper #60

**Hibbs Award Nominee for Best Clinical Paper

Adult Spinal Deformity Surgery: Complications And Outcomes In Patients Over Age 60

Michael D. Daubs, MD (Washington University); Lawrence G. Lenke, MD; Gene Cheh; Georgia Stobbs; Keith
H. Bridwell, MD

Purpose: To evaluate the rate of complications and outcomes in patients over the age of 60 years undergoing major
spinal deformity surgery requiring a minimum 5 level arthrodesis procedure.

Methods: 40 patients who were 60 years of age or older underwent a thoracic/lumbar arthrodesis procedure
consisting of 5 levels or more. Diagnosis included degenerative scoliosis(17), fixed sagittal imbalance(13), adult
presentation of idiopathic scoliosis(8), ankylosing spondylitis(1), and neurofibromatosis(1). Pre-operative
comorbidities, operative and post-operative complications were recorded.

Results: There were 33 females and 7 males with an average age of 66 years (range, 60-85). The average follow-up
was 62 months(range 24-224). 31(77%) of patients had at least one comorbidity. 24( 60%) patients had at least one
prior spinal surgery. 18(45%) underwent both an anterior and posterior arthrodesis. An average of 9 levels(range 5-
15) were fused in each case. The average total surgical time( including combined surgery) was 603 minutes(10
hours). Average total EBL was 1942cc(range 300-5500cc), and an average of 5 units of blood were transfused. The
total average hospital days were 14(range 6-43). The overall complication rate was 37%. 12 patients( 27%) had at
least one minor complication and 7(16%) had at least one major complication. 14 (27%) of patients required
additional surgery most commonly for pseudarthrosis and implant complications. Oswestry Disability Index scores
improved by a mean of 23 from a pre-op of 49 to a post-op of 27 (p< 0.0001).

Conclusions: Adult spinal deformity surgery in older patients is demanding and requires a significant amount of
surgical time, hospitalization and blood transfusion requirements. The overall complication rate is 37%, the major
complication rate 16% and the re-operation rate 27%. Patients reported significant improvement in function with
long term follow-up. Patient selection in this high risk group is extremely important.
Paper #61

**Hibbs Award Nominee for Best Clinical Paper

Loss of Spinal Cord Monitoring Signals in Children during Thoracic Kyphosis Correction with Spinal
Osteotomy: Why Does it Occur and What Should You Do?

Gene Cheh, MD; Lawrence G. Lenke, MD; Yongjung J. Kim, MD; Michael D. Daubs, MD; Anne Padberg, MS
(Washington University School of Medicine); Craig A. Kuhns, MD; Georgia Stobbs, Marsha Hensley, MD

Purpose: To determine the incidence of, etiology for, and correction method of neurogenic motor-evoked potential
(NMEP) loss associated with pediatric spinal osteotomies for kyphosis correction.

Methods: 36 pediatric patients with useful lower extremity function underwent a corrective spinal osteotomy for
rigid kyphosis at one institution. Diagnoses included Scheuermann’s kyphosis (n=13), congenital kyphosis (n=5),
hemivertebra (n=6), neuromuscular kyphosis (n=4), connective tissue disorders (n=3), neurofibromatosis (n=2), and
miscellaneous (n=3). All osteotomies performed were at the spinal cord level, which included vertebral column
resection (n=6), posterior hemivertebra excision (n=6), pedicle subtraction osteotomy (n=3), and multiple Smith-
Petersen osteotomies (n=21). Average preoperative kyphosis was 79º (range 32-140º) and the average correction
was 37º (range 0-59º).

Results: There were seven cases (19%) of intraoperative NMEP loss. The signal loss occurred prior to any
corrective maneuver (n=1), during corrective maneuvers (n=5), and 70 minutes after completion of correction (n=1).
Correction of Scheuermann’s kyphosis through multiple Smith-Petersen Osteotomies (5/14, 36%) and performance
of a thoracic vertebral column resection (2/6, 33%) demonstrated the highest risk techniques for NMEP signal loss.
With elevation of blood pressure (mean arterial pressure >80mmHg) and release of correction (see Figure), NMEP
signals reappeared in all cases in an average 18 minutes (range 5-52), and surgery was successfully completed.
Postoperatively, all patients had a normal neurological exam. A false negative NMEP response (undetected
neurologic complication) occurred in one patient. The patient was treated by immediate rod removal and staged
reinsertion without neurologic sequelae.

Conclusions: The incidence of intraoperative NMEP signal loss during spinal osteotomies for spinal cord level
kyphosis correction in pediatric patients was 19%. Correction maneuvers combined with hypotension were the
common etiologies. Reduction in the degree of kyphosis correction and blood pressure elevation reversed the signal
loss in all cases. With early detection using NMEP monitoring, corrective action can be taken and neurologic injury
avoided.
Paper #62

**Hibbs Award Nominee for Best Basic Science Paper

Triggered Electromyographic Threshold in the Intercostals Muscle to Evaluate the Accuracy of High
Thoracic Pedicle Screw Placement

Juan Carlos Rodriguez Olaverri, MD, PhD (Hospital Miguel Servet); Gema De Blas; Gabriel Piza Vallespir;
Jesus Burgos, MD; Eduardo Hevia, MD; Javier Vicente; Ignacio Sanpera; Pedro Domenech; José Maruenda, MD;
Regidor Ignacio

Introduction: A prospective clinical study of thoracic pedicle screws monitored with triggered electromyographic
testing was made to evaluate the sensitivity of recording intercostals muscle to assess upper thoracic screw
placement.

Methods: A total of 300 high thoracic screws were placed in 50 consecutive patients. Screws placed from T3 to T6
were evaluated using an ascending method of stimulation until a compound muscle action potential was obtained
from the intercostals muscle. Screw position was then evaluated after surgery using computed tomography (CT).
The CT results were compared with evoked EMG threshold values. Postoperative CT scans were read by a staff
orthopaedic spine surgeon and a musculoskeletal radiologist

Results: Fifteen screws (5 %) showed penetration on postoperative CT scans. Eleven screws showed medial cortical
breakthrough ( 3.6 %) 6 had stimulation thresholds ≤ 6 mA and, 5 had stimulation thresholds between 6-10 mA but
the values had 60-65% decreased from the mean. Four screws (1.3 %) showed lateral cortical breakthrough with
stimulation thresholds > 20 mA. Of the 300 screws with thresholds between 10- 20 mA, 285 (95 %) were within the
vertebra. No postoperative neurological complications were noted in any of the 50 patients.

Conclusion: In our series, stimulation thresholds between 6 - 20 mA coupled with values 60-65% decreased from
the mean have a 98 % negative predictive value, suggesting that cortical violation is highly unlikely. Stimulation
thresholds of ≤ 6 and >20 mA should alert the surgeon to suspect a medial and lateral pedicle wall breach
respectively. Although judgment of screw placement should not depend solely on stimulation thresholds, pedicle
screw stimulation may provide rapid and useful intraoperative information on screw placement during procedures
involving the use of thoracic pedicle screws.
Paper #63

**Hibbs Award Nominee for Best Clinical Paper

Detection Of Impending Neurologic Injury During Surgery For Adolescent Idiopathic Scoliosis: A
Comparison Of Transcranial Motor And Somatosensory Evoked Potential Monitoring In 1121 Consecutive
Cases

Joshua D. Auerbach MD; Daniel M. Schwartz, PhD, DABNM; Denis S. Drummond, MD; Kristofer J. Jones,
BA; John M. Flynn, MD; Yaser El-Gazzar, BA; Thomas McPartland, MD; J. Andrew Bowe, MD; Samuel Laufer,
MD; Peter D. Pizzutillo, MD; Richard Bowen, MD; John P. Dormans, MD

Purpose: This study sought to determine the efficacy, quality and accuracy of somatosensory evoked potential
(SSEP) and transcranial electric motor evoked potential (tceMEP) monitoring, both individually and combined for
detecting impending iatrogenic neural insult during scoliosis surgery.

Methods: We reviewed the intraoperative monitoring records of 1121 consecutive patients (834 females, 287 males,
mean Age=14.8 years) from four institutions monitored by a single, standardized multi-modality monitoring
protocol during surgery for adolescent idiopathic scoliosis between 2000-2004. Significant neurophysiologic change
(alert) was defined for SSEPs as an amplitude reduction of at least 50% from baseline, while that for tceMEPs was
greater than or equal to a 65% amplitude loss either unilaterally or bilaterally.

Results: In total, 3.4% of patients (38/1121) met the definition of significant signal change (i.e. alert). Among these,
24% (9/38) were related to hypotension and corrected with blood pressure augmentation (average MAP at alert:
59mmHg). The remaining 29 alerts were related directly to a surgical maneuver. Of those 29, 16/29 (55%) had
motor evoked amplitude changes of > 65% without any evidence of SSEP changes. Three events were related to
segmental vessel clamping, and 90% (26/29) were related to instrumentation. Thirty-five percent (9/26) of patients
with instrumentation-related alerts awoke with a motor or sensory deficit, all of which were detected by tceMEP, but
44% (4/9) of which were not detected by SSEP. On average, when SSEP changes were detected, they lagged behind
tceMEP changes by 4.8 minutes (range: 0-10 minutes).

Conclusions: Overall, tceMEP monitoring was 100% sensitive and 100% specific in the detection of impending
neurologic injury. SSEP monitoring, however, had a sensitivity of only 55.5% and specificity of 100%, and lagged
behind tceMEP changes by 4.8 minutes on average. In this large, multicenter series, tceMEP was a more sensitive
and rapid method of detecting an impending neurologic injury.
      Paper #64

      Is Spinal Deformity Surgery in Patients with Cerebral Palsy Truly Beneficial? A Patient/Parent Evaluation.

      Kota Watanabe, MD, PhD (Washington University School of Medicine); Lawrence G. Lenke, MD; Michael
      D. Daubs, MD; Kei Watanabe, MD; Keith H. Bridwell, MD; Georgia Stobbs; Marsha Hensley, MD

      a - Medtronic Sofamor Danek
      d - Medtronic Sofamor Danek
      e - Medtronic Sofamor Danek

      Purpose: To evaluate the radiographic results of spinal deformity surgery in cerebral palsy (CP) patients and to
      determine if the patient/parent felt it was beneficial.

      Methods: Neuromuscular patient evaluation questionnaires were answered retrospectively by 81 patients/family of
      CP children undergoing spinal fusion. The average follow-up was 4.2 years (range 2-14). The questionnaires were
      designed to assess patient function, pain, cosmesis, self-image, and the quality of life of the patient and
      parent/caregiver. Results of the questionnaires were divided into categories, graded, and analyzed. Radiographic
      data and complication rates were also analyzed.

      Results: Overall satisfaction rate was 92%. 87% reported improvement with sitting balance, 94% with cosmesis,
      51% in overall activity level, and 66% in quality of life of the patient/parent. The postoperative complication rate
      was 33%. The mean preoperative Cobb angle of the main curve was 86º (range 50-128º), which corrected to 33º
      (range 2-76º) (58% correction rate) postoperatively. The spinal coronal balance parameters of pelvic obliquity,
      clavicle angle, and C7 plumbline were significantly improved in all cases. (See table)

      Conclusion: Despite the perioperative difficulties seen with CP patients, the overall satisfaction rate with the
      deformity surgery was high (92%). 87% reported improvement in sitting balance, 94% improved cosmesis, and 66%
      felt their quality of life had improved. The radiographic parameters of coronal balance significantly improved in all
      cases. Our data supports the argument that spinal deformity surgery in patients with CP significantly benefits both
      patient and family.


         Age Mean
   15.2yo         (9-21)
                                   Preoperative                 Postoperative                     %Correction Rate
                                      Mean                         Mean                 p             Mean
Main Curve Cobb*                85.9º        (50-128)         35.7º       (2-76)     6.6E-14      57.6%      (22-96)
C7-CSVL*                     115.3mm          (5-315)       53.4mm       (4-162)     0.0001
Pelvic Obliquity*               23.6º         (0-128)         6.4º        (0-23)     0.0001
Clavicle Angle*                 11.6º         (0-40)          4.7º        (0-16)     0.00032
                                                  +
T5-T12                          32.6º        ( ‫)09 -2־‬        28.2º       (3-67)     0.15494
                                                   +                            +
T10-L2                          17.3º       ( ‫)16 -74־‬        2.3º     ( ‫88881.0 )42 -32־‬
                                                  +
T12-S1                         ‫6.94 ־‬º     ( ‫)001 -14־‬       ‫4.65 ־‬º ( ‫88881.0 )011+-95־‬
Paper #65

Tranexamic Acid Diminishes Intraoperative Blood Loss in Duchenne Muscular Dystrophy Scoliosis Spinal
Fusions

Frederic Shapiro, MD (Children’s Hospital Boston); David Zurakowski, MD; Navil Sethna

PURPOSE: We compared intraoperative blood loss with and without the synthetic anti-fibrinolytic agent
tranexamic acid (TXA) during spinal fusion surgery for scoliosis in Duchenne muscular dystrophy (DMD).

METHODS: All patients underwent posterior spinal fusion with the same technique using 2 rods and multiple
sublaminar wires. Group 1: TXA was not used in 36 patients. The mean number of levels fused was 14.3. Group 2:
TXA was used in 16 patients. TXA dose was 100mg/kg in solution over 15 minutes before incision followed by an
infusion of 10 mg.kg-1.h-1 during surgery. The mean number of levels fused was 14.7. Standardized measurements
of intraoperative blood loss were used. Assessment A compared total amount of blood loss in milliliters (ml) per
patient and assessment B calculated blood loss as a percentage in relation to estimated blood volume [estimated
blood loss (EBL)/estimated blood volume (EBV) X 100]. The EBV was calculated to be 70 ml/kg (body weight).

RESULTS: A: Mean blood loss with TXA was 1976+/-860 ml (range 760-4000) and without TXA was 3382+/-
1795 ml (range 600-9580) [highly significant difference (Student t=3.81, p<0.001)]. Blood loss with TXA was
decreased by 42% to only 58% of the blood loss in patients not treated with TXA. B: Accounting for patient weight
and estimated blood volume, mean % blood loss with and without TXA was 49+/-30% vs. 111+/-67% (Student
t=4.63, p<0.001). This more physiologic indicator shows that blood loss with TXA was decreased by 56% to only
44% that of patients not treated with TXA. No complications from TXA therapy were observed.

CONCLUSION: Intraoperative TXA significantly reduces blood loss in DMD patients undergoing posterior spinal
fusion spinal for scoliosis.
Paper #66

Results And Complications Following Surgical Treatment of Scoliosis Associated with Spinal Muscular
Atrophy: The Experience at One Institution.

Stefan Parent, MD, PhD; Reinhard Zeller, MD; Dror Ovadia, MD; Danielle Leclair-Richard, MD; Brigitte
Estournet-Mathiaud, MD; Annie Barois, MD

Introduction: Spinal Muscular Atrophy (SMA) is a disease of the anterior horn cells that is transmitted genetically
and is often associated with the development of scoliosis. The treatment of these patients is often complicated by the
presence of a severe restrictive pulmonary disease.

Methods: Retrospective review of all patients with SMA having undergone surgical correction of their spinal
deformity at one institution. All patients underwent posterior spinal fusion performed by the same surgeon. Thirty-
six patients underwent a complementary anterior spinal fusion. Chart review, pre-op and latest greater than 2 year
post-op radiographs, pulmonary function tests and anesthesia records were reviewed for all patients.

Results: Complete data was available for 78 of 84 patients. Mean pre-operative and post-operative radiographic
measures can be found in table 1. Mean anesthesia time was 481 (range 350-780) and mean operative time was 402
minutes (range 280-660). When anterior surgery was performed, mean operative time was 203 minutes (range 80-
420). Blood loss averaged 1498 cc’s (range 236-4297). There were 10 (12%) post-operative infections of which 7
(8%) were considered deep infections requiring surgical debridement. Other complications included atelectasis(5),
tibia fracture (autograft donor site in 3), pneumonia (3), ARDS (1), tracheal stenosis (1), tension pneumothorax and
death (1). A total of 49 complications were found in 35 patients (41%).

Discussion: Scoliosis associated with SMA remains a challenging clinical problem. Although the rate of
complication is high, all but one patient survived the surgery with improved coronal, sagittal and pelvic balance
while maintaining their vital capacity. Patients undergoing surgery and their relatives should be made aware of the
risks associated with the complex nature of the disease.

Conclusion: Patients with SMA should be overseen by an experienced multidisciplinary team with knowledge of
the pre-operative and post-operative management.



      Measurement                   Pre-op (range)                  Post-op (range)                  p value

      Cobb (major)                 78.9º (31 – 155º)                40.5º (6 – 82º)                  0.000

      Cobb (minor)                  49.3º (18 – 87º)               31.4º (12 – 65º)                  0.000

      Cobb Sagittal                42.9º (-40 – 127º)              24.8º (-10 – 60º)                 0.000

      Cobb T12-S1                  45.9º (-80 – 109º)              61.9 º (37 – 93º)                 0.004

      Cobb T5-T12                   23.6º (-6 – 68º)                13.9º (-3 – 39º)                 0.061

    Pelvic Obliquity                14.9º (1 – 48º)                  6.6º (0 – 21º)                  0.000
Paper #67

The Morbidity of an Anterior Thoracolumbar Approach in Adult Patients with Greater than Five-Year
Follow-Up

Youngbae B. Kim, M.D., Lawrence G. Lenke, MD; Yongjung J. Kim, MD; Young-Woo Kim, MD; Kathy
Blanke, RN (Washington University School of Medicine); Georgia Stobbs; Keith H. Bridwell, MD

Purpose: To analyze the complications and patient satisfaction related to an anterior thoracolumbar approach in the
staged treatment of adult spinal deformity.

Methods: A specific questionnaire was used to evaluate long-term follow-up (average 10.1 years, range 5-19) of 28
adult patients who underwent spinal deformity surgery performed through an anterior thoracolumbar approach.
Thirteen patients had over a 10-year follow-up and nine were between 5 to 10 years postoperative. The
questionnaire is composed of detailed scar-related sub-questions of pain, appearance, bulging, daily life, and
patient’s personal opinion of surgery.

Results: The average age and number of anterior fusion levels was 50.5 (range 32-74) and 5.4 (range 2-10),
respectively. Although 92.8% patients (26/28) were satisfied with the results of their surgery in general, some of
patients were dissatisfied with aspects related to their anterior incision. For the pain domain, seven patients (25%,
one with more than 10 year follow-up and six with 5 year) rated their pain over the thoracolumbar scar as moderate
to severe. Six patients (21.4%) felt they had a poor outcome related to their postoperative appearance. Fourteen
patients (50%) had bulging of their scar, two were surgically indicated for repair, and one patient had multiple
surgical repairs. Seven patients (25%) showed limitations in activities of daily living due to their anterior incision.
One patient with more than 10 years follow-up and four with more than 5 years follow-up felt they were getting
worse.

Conclusion: This is the first long-term (min. 5 years) follow-up study focusing on patient outcomes following an
anterior thoracolumbar approach for spinal deformity treatment. This approach appears to be associated with a high
rate of postoperative pain (25%), bulging (50%), and functional disturbance (25%). Therefore, surgeons should use
caution when recommending this approach to future adult spinal deformity patients.
Paper #68

Complications of Dual Growing Rod Technique in Early Onset Scoliosis: Can We Identify Risk Factors?

Behrooz A. Akbarnia, MD; Marc A. Asher, MD; Ramin Bagheri, MD (San Diego Center for Spinal
Disorders); Oheneba Boachie-Adjei, MD; Sarah Canale, BS; Patricia A. Kostial, RN, BSN; David Marks, MSc,
FRCS; Richard E. McCarthy, MD; Michael J. Mendelow, MD; Connie Poe-Kochert, CNP; Paul D. Sponseller,
MD; George H. Thompson, MD

D - DePuy Spine
E – DePuy Spine

Purpose: To identify factors influencing complications in patients with early onset scoliosis (EOS) who underwent
the dual growing rod technique.

Methods: Between September 1987 and August 2003, 48 patients with EOS underwent initial surgery using dual
growing rods and had a minimum of 2 years follow-up, with 29 patients developing complications. Complications
were divided into 4 groups: implant, wound, alignment, and general. Relations analyzed included age at surgery,
diagnosis, curve magnitude, initial correction, follow-up length, and lengthening frequency. Our study received IRB
approval.

Results: Fifty-five complications occurred in 29 patients. Twenty-seven implant, 14 wound, 5 general and 9
alignment-related complications occurred. Eighteen complications resulted in 23 unplanned procedures. Thirty-
seven complications were addressed during planned procedures. Average age of the uncomplicated group was
81.9mos and 61.5mos in the complicated group. Average follow-up of the uncomplicated group was 46.6mos
compared to 67.1mos in the complicated group. Average interval between lengthenings was 8.1mos (uncomplicated
group) versus 11.8 (complicated group). Both groups had an average Cobb angle >70 prior to initial surgery.
Diagnosis was insignificant except for Infantile Idiopathic Scoliosis (IIS), where 8 of 9 total patients had implant-
related complications. The implant complication group had 5 of 27 complications requiring unplanned surgeries. Six
deep infections occurred. Additionally, 2 of 3 wound problems evolved into deep infections and 2 of 4 superficial
infections became deep.

Conclusion: At initial surgery, younger patients had higher complication rates. More complications occurred with
longer treatment periods. Most implant problems were addressed during planned surgeries. High correlation existed
between diagnosis (IIS) and implant-related problems. Patients whose lengthening intervals were ≤7mos had fewer
implant complications but more wound complications. Patients whose intervals were ≥7mos had more implant
complications but fewer wound complications. Wound problems should be addressed aggressively to prevent deep
wound infections. This technique has a high but manageable complication rate.
Paper #69

Combining Excellence with Relevance in A Spine Outreach Program for Underserved Countries: A Report of
Early and Late Complications

Oheneba Boachie-Adjei, MD (Hospital for Special Sugery); AO Addo, MD; H.B. Calder, MD, PhD; Gina
Charles; Jerome Jones, MD; Matthew E. Cunningham, MD, PhD; Stephen Lyman, PhD; Francisco Perez-Grueso,
MD; Bettye Wright, PA, RN

d – DePuy Spine
e – Oheneba Boachie-Adjei, MD

Purpose: (1) to evaluate the relevance of instituting a complex spine surgery program in underserved nations where
facilities and expertise are lacking. (2) to evaluate the comprehensive surgical treatment programs provided, and (3)
to evaluate associated complications of the programs.

Methods: Between August 1998 to November 2005, 190 patients in Ghana, West Africa (141) and Barbados, W.I.
(49) underwent spine surgery for various spine disorders. There were 116 females and 74 males. Average age 67.2,
years (range 1 to 77); 21 years (91 patients). Diagnostic categories include 108 scoliosis/kyphosis (13 post TB
kyphosis patients), 20 degenerative disc disease, 12 spinal stenosis, 18 spondylolisthesis, 4 cervical spondylosis, and
27 other related diagnosis. There were 201 posterior spinal fusions, 4 anterior only spinal fusions, 17 same day
ASF/PSF procedures, and 33 posterior decompressions. One patient required intubation following a combined
anterior/posterior; a tracheotomy performed postoperatively and was later decanulated.

Results: 121 patients have greater than 2 year follow up. There were 20 complications in 18 patients (9.4%). There
were two mortalities from pulmonary embolism. Late complications included pseudoarthosis in 1 patient, and 3 late
infections (see tables). There were no permanent cord injuries.

Conclusions: In a safe and relatively cost effective manner, and without compromise, patients with major spinal
disorders in underserved and developing countries can receive the benefits of state of the art spinal care with
acceptable complication rate, compared to SRS MM data. A comprehensive review and patient selection process is
an essential ingredient to achieving success in such a global outreach program.
                                            (Paper #69 attachment)

Table 1. Complications by Type comparing Study Population to 2004 SRS Data

                                 Study Population (190 pts)   SRS Population (20,790 pts)

       Complication               Number of     Complicati     Number of      Complicati    p-value
                                 Complication    on Rate      Complication     on Rate
                                     s             (%)            s              (%)



Fatal Complications:

       Pulmonary Embolism             2            1.1%              15         0.07%        0.01



Non-fatal Complications:

              Implant related         8            4.21%             127         0.6%       <0.0001

   Nerve root injury (partial)        2            1.05%             123         0.6%        0.31

                    Infection         3            1.58%             421         2.0%        0.99

                Neurological          0              0               147         0.7%        0.65

            Other pulmonary           3            1.58%             28          0.9%        0.002

             Pseudoarthrosis          1            0.5%              --           --          --

             Adding on with           1            0.5%              --           --          --
             decompensation



Non-fatal complications by initial diagnosis:

                    Scoliosis        10            5.26%             452        10.8%        0.02

                    Kyphosis          8            4.21%             103        16.4%       <0.0001

 Degenerative spinal disorder         2            1.05%             490         5.0%        0.006

                        Other         1            0.5%              177         7.5%       <0.0001
Paper #70

Risk Factors for the Development of Delayed Infection Following Posterior Spinal Fusion and
Instrumentation for AIS

Daniel J. Sucato, MD, MS (Texas Scottish Rite Hospital); B. Stephens Richards, III, MD; Christine Ho

Purpose: To define risk factors for the development of delayed infections following posterior spinal fusion and
instrumentation (PSFI) by comparing those patients who developed this complicaton to a randomly-selected group
of patients who did not. .

Methods: In this retrospective, IRB approved study, 1046 patients were identified whose index PSFI for AIS was
between Jan 1988 and Dec 2003. Those patients who required treatment for delayed infections were identified
(group 1).A random selection of patients who did not develop delayed infections (group 2) was made in a ratio of
3:1 (no infection:infection). The two groups were compared using statistical methods.

Results: There were no differences between groups with respect to age, gender, or ethnicity. Parameters which were
associated with infection (group 1) included: a significant past medical history, surgeon, less surgical time, the
sterile prep wash of the patient, harvesting of the left iliac crest (compared to the right), a more distal fusion level
(distal end vertebra L1-L4, 82.9% infection group, vs. 64.9% no infection group), the use of two crosslinks (77.1 vs.
58.2%), incidence of drain usage (38.4% vs. 86.7%) and more return of cell saver (311.0 vs 229.7 cc). Most patients
had the same antibiotic regimen pre and post-operatively. Factors which were not associated with delayed infection
included: BMI, the number of anchor points utilized, use of allograft bone, and the total number of levels
instrumented.

Conclusions: Several factors were identified which are associated with the development of delayed infection. The
occurrence of a delayed infection is most likely multi-factorial, including surgeon variability, surgical technique, and
number of crosslinks. Postoperative use of a drain may be important to avoid delayed infection.
Paper #71

Transpedicular Expanded Eggshell Technique Vertebral Column Resection for Serious Rigid Kyphoscoliosis
in Adults

Yan Wang, MD, PhD; Yonggang Zhang, MD; Xuesong Zhang, MD; Songhua Xiao, MD; Zheng Wang, MD

Study Design: Retrospective study.

Objectives: To report a technique of transpedicular expanded eggshell technique vertebral column resection (VCR)
through a single posterior approach and its preliminary results in the treatment of severe congenital rigid
kyphoscoliosis to adults.

Summary of Background Data: Transpedicular eggshell osteotomies and vertebral column resection is a
formidable operation reserved for rigid severe deformities. The authors devised a technique combined two
techniques in treatment of adult congenital kyphoscoliosis through a single posterior approach.

Methods: From 2001 to 2003 sixteen serious rigid congenital kyphoscoliosis deformity adult patients were
reviewed, who were treated by posterior transpedicular expanded eggshell technique VCR, 6 males and 10 females
with a mean age of 31.8(range 21.5-44.2 years old). Three-dimensional reconstructive images were used for
preoperatively osteotomy levels selecting and accurately pedicle screws placing. The surgery consisted of one-stage
posterior transpedicular eggshell technique, and then expanded the eggshell to the adjacent inter-vertebra space,
range of resection of the vertebral column at the apex of the deformity, including AV and both cephalic and caudal
adjacent wedge vertebra. Posterior elements were removed, after completion of the VCR, closure was obtained by
gradually cantilever and compression technique.

Results: Average 1.6 vertebra were resected. Mean operation time was 256 min with average blood loss of 2250 ml.
Mean 32mm shorten was measured during operation, and 22 mm lengthen in standing post-operation. In this group,
average follow-up was 2.6 years (range 2.1–3.5 years). Deformity correction was 52.3% in the coronal plane and
75.1 in the sagittal plane. Complications were encountered in 4 patients: 2 transversal spinal injury and 2 root
injuries (all incomplete).

Conclusions: Posterior transpedicular expanded eggshell technique VCR is an effective alternative for serious
congenital rigid kyphoscoliosis in adults.
Paper #72

Transpedicular Osteotomy in Revision Scoliosis Surgery

Sebastien Charosky, MD; Ian Harding, FRCS (Orth) Daniel Chopin, MD; Raphael Vialle, MD

Purpose: To evaluate the indications, outcome, risk factors and complications of transpedicular osteotomy (TPO) in
revision scoliosis surgery

Methods: We evaluated patients undergoing TPO for revision scoliosis surgery at our institution between 1989 and
2004 with a minimum follow up of 2 years. Demographic data, anaesthetic risk factors, peri-operative data and
complications were recorded. Radiographs pre-operatively, post-operatively and at last follow up recorded sagittal
balance, coronal balance, lumbar lordosis and pelvic parameters. Functional outcome was measured using the
Whitecloud score.

Results: 21 patients (24 TPO’s) mean age 48.7 years with mean follow up 4.4 years fulfilled criteria for study. All
cases had fixed sagittal imbalance pre-operatively. Mean operative time was 4.6 hours and mean transfusion
requirement was 2.3. units. A significant improvement (p<0.03) in sagittal imbalance was gained (although in 3
cases of pseudarthroses this was partially lost) and the post-operative lumbar lordosis correlated closely significantly
pelvic incidence (p<0.03). Functional outcome was good/excellent in 67% cases. We report 28 complications. 22
early included 4 dural tears, cardiac decompensation with reduction, 5 neurological deficits including one secondary
to haematoma which was evacuated and the patient made a good recovery at 6 months, 2 UTIs, IVI infection,
superficial wound infection and extension of metalwork due to early proximal decompensation. Late complications
included infection (8 years), removal of prominent metalwork, radiculopathy due to screw (6 months) and 3
pseudarthroses. There was no statistically significant correlation of complication with weight, ASA grade or
smoking.

Conclusion: TPO in revision scoliosis is an effective method of correcting both coronal and sagittal imbalance but
is not without complication, although good functional outcome is achieved in most patients. It is important to
consider pelvic parameters pre-operatively to plan the level and magnitude of TPO required.
Paper #73

**Hibbs Award Nominee for Best Clinical Paper

Results of Lumbar Pedicle Subtraction Osteotomies for Fixed Sagittal Imbalance: A minimum 5 years follow-
up study

Yongjung J. Kim, MD (Washington University School of Medicine); Keith H. Bridwell, MD; Lawrence G.
Lenke, MD; Gene Cheh, MD; Christine Baldus, LPN

Purpose: No one has reported results of pedicle subtraction osteotomies with 5-10 year follow-up. The purpose of
this study is to report results at least 5 years after pedicle subtraction osteotomies for iatrogenic sagittal imbalance.

Method: Thirty-four consecutive patients with sagittal imbalance (28 females/ 6 males, average age at surgery 53
years) treated with lumbar pedicle subtraction osteotomies (1 L1, 13 L2, and 20 L3) at one institution were analyzed
(average follow-up 5.8 years, range 5-7.6 years). Radiographic analysis including various sagittal parameters and
clinical outcomes analysis using Oswestry questionnaire and the Scoliosis Research Society questionnaire was
performed.

Results: There were no significant radiographic changes between the 2 years postoperation and the ultimate follow-
up (the average lumbar lordosis 43 at 2 years postoperation à 45 at ultimate follow-up and the sagittal vertical axis
4.4cm at 2 years postoperation à 5.3cm at ultimate follow-up). There was no degradation in Oswestry score (2 years
postoperation 13 + 8.4 and ultimate follow-up 10 + 8.0) and SRS outcome score (74% at 2 years postoperation and
74% at ultimate follow-up). Patients reported good self-image (74% at 2yrs postoperation and 85% at ultimate
follow-up), good satisfaction (91% at 2yrs postoperation and 85% at ultimate follow-up), moderate pain (68% at
2yrs postoperation and 64% at ultimate follow-up), and function (64% at 2yrs postoperation and 67% at ultimate
follow-up) subscales. Among 10 pseudarthroses (29%) in 8 patients, 5 pseudos developed 2-4 years postoperation
(no pseudo after 4 years postoperation). There was no pseudarthrosis at the osteotomy level (8 pseudos at TL
junction and 2 at LS junction), but at the levels added to the previous fusions.

Conclusion: There were no significant radiographic and clinical outcome changes between the 2 years and the 5 to
8 years postoperation following lumbar pedicle subtraction osteotomy for fixed sagittal imbalance.
Paper #74

Correction Surgeries for Severe Cervical Kyphotic Deformities with Myelopathy due to Various Etiologies

Takachika Shimizu (Gunma Spine Center), Keisuke Fueki, Masatake Ino, Naofumi Toda, Tanouchi Tetsu,
Manabe Nodoka

Purpose: The aim of this presentation is to describe our clinical experience and results of correction surgeries for
severe cervical kyphotic deformity with myelopathy.

Materials and Methods: Seventeen cases with cervical kyphotic deformity due to various etiologies were operated
on. Kyphosis was located at the craniovertebral junction (CVJ) and subaxial region in 13 and 4 cases, respectively.
There was congenital kyposis in 10 (CVJ: 8, subaxial: 2), iatrogenic in 3 (post-laminoplasty: 2, C1/2
pseudoarthrosis: 1), post-traumatic in 1, Recklinghausen' disease in 1, post-infectious in 1, and unknown etiology in
1. In 4 subaxial kyphosis cases, pre-op. kyphotic angles were over 45 degrees (46-72, avr. 60 degrees). Pre-op.
clivoaxial angles were 109-126 degrees (avr. 115 degrees) in CVJ kyphosis cases. Posterior loop/rod type
instrumentations with sblaminar wires and/or pedicle screws were used in all cases. Mean follow up period was 3.2
years. (2-12.5 years). Correction status, neurological recovery evaluated by JOA score, respiratory and swallowing
disturbances were examined.

Results: Kyphotic deformity was nicely corrected, and solid fusion was obtained in all cases. Average correction
angle was 54 degrees (39-75) in subaxial kyphosis, and 28 degrees (14-47) in CVJ kyphosis. Respiratory problems
and difficulty in swallowing improved after the surgery in all cases. Pre- and post-op. mean JOA score were 6.5 and
12, respectively.

Discussion: Interlaminar segmental decompression prior to correction was one of the key to avoid additional
compression to the cord by protrusion of the ligamentum flava. In cases with the main compression factors at the
CVJ, transoral anterior decompression is essentially required. We did not have the ability to do that, and instead
performed posterior realignment by widening the clivo-axial angle to reduce the ventral compression to the
neuroaxis using powerful posterior instrumentation. The results surpassed our expectations, and post-op.
neurological improvement was obtained in all cases.
Paper #75

The Relationship Between Thoracic Hyperkyphosis And The Scoliosis Research Society Outcomes
Instrument

Peter O. Newton, MD (Children’s Hospital and Health Center); Maty Petcharaporn, MD; Jeff Pawelek;
Tracey Bastrom, MA; Baron S. Lonner, MD

a - DePuy Spine
e - DePuy Spine

Purpose: To evaluate the relationship between thoracic hyperkyphosis and patient quality of life measures as
determined by the Scoliosis Research Society (SRS) outcomes instrument.

Methods: Data from the SRS outcomes instrument was collected from patients with Scheuermann’s kyphosis, as
well as those with normal spinal alignment. A total of 45 patients with thoracic kyphosis ≥ 45 were compared to 27
normal patients with thoracic kyphosis < 45 . Correlation analysis was performed to identify significant relationships
between the magnitude of the major kyphotic curve and the four SRS outcome questionnaire domains (total pain,
general self-image, general function, and activity). Lower SRS scores indicate an increase in symptoms.

Results: The average age of the subjects was 15 + 2 years (range 10 to 18). The thoracic kyphosis varied between
11 and 95 degrees for all subjects. Significant negative correlations were found between kyphosis magnitude and the
four pre-operative domains of the SRS outcomes questionnaire. Patients with greater kyphosis reported significantly
lower scores on pain, self-image, function (all p<0.001) and activity as compared to normals. Of the 4 domains, self
image had the highest correlation with kyphosis magnitude while activity had the lowest.

Conclusion: These findings indicate that higher kyphosis magnitudes were associated with increased pain, lower
self-image, and decreased function. Increased kyphosis was also associated with decreased activity, however the
relationship in this domain was not as strong as in the other three. Scheuermann’s kyphosis patients were
significantly more symptomatic than normals in all domains. The r-values for this analysis of kyphosis (0.25 - 0.68),
in fact were substantially greater than those previously reported for scoliosis magnitude vs SRS Questionnaire scores
(0.16 - 0.26), suggesting this instrument may be even better suited for the evaluation of hyperkyphosis patients.

                     Correlation Analysis (Kyphosis magnitude vs SRS Questionnaire Scores)
                     SRS Questionnaire Domain                   r value              p value
                                 Pain                           -0.437               <0.001
                              Self image                        -0.676               <0.001
                               Function                         -0.410               <0.001
                               Activity                         -0.254                0.028
Paper #76

Closing–opening Wedge Osteotomy of Spine to Correct Severe Post-Tubercular Kyphotic Deformities of the
Spine: A Three- year Follow-up of 13 Patients.

S Rajasekaran, MS, DNB, FRCS (Ganga Hospital)

Introduction: We describe here a closing-opening osteotomy for correction of post-tubercular deformity which
shortens the posterior column, opens the anterior column appropriately to correct the deformity without compromise
to the spinal cord.

Patients and methods: Thirteen patients with kyphotic deformity due to healed spinal tuberculosis (eight males;
five females) with an average age of 14.84±7.19 years (range 7-32 years) formed the patient group. There were eight
thoraco-lumbar and five thoracic deformities. The number of vertebrae involved in the fusion mass ranged from two
to five. Preoperative kyphosis averaged 64.2 ±27.6 (range 26 -104 ). The average vertebral body loss was 2.07±0.9
(range 1.1-4.1). The neurological status was normal in nine patients, Frankel’s Grade D in three patients and Grade
C in one patient. All patients were operated by posterior approach.

Result: Average operating time was 4½ hours (3.2–5.4 hours) with blood loss of 810 ml (range 500-1600 ml). The
post-operative kyphosis averaged 33.5 ±24 (range 8 -71 ). The average deformity correction was 30.70±8.70 (range
18 -52 ) following surgery. The percentage correction of kyphosis achieved was 53.1±16.8% (range 26-77%).
Anterior reconstruction was performed using rib grafts in four, tricortical iliac bone graft in five, cages in two, and
bone chips alone and fibular graft in one patient each. No patients with normal preoperative neurological status
showed deterioration in neurology after surgery. The last follow-up was at an average of 42±5 months (range 31-54
months). The average loss of correction at the last follow-up was 4.20 (range 30-60). Complications were superficial
wound infections in two, neurological deterioration in one, temporary jaundice in one and implant failure requiring
revision in one.

Conclusion: Single stage opening-closing wedge osteotomy is an effective method to correct severe kyphosis in
healed spinal tuberculosis.
Paper #77

**Hibbs Award Nominee for Best Basic Science Paper

“rhBMP-2 (ACS and CRM Formulations) Overcomes Pseudoarthrosis in a New Zealand White Rabbit
Posterolateral Fusion Model”

Jonathan N. Grauer, MD; James P. Lawrence, MD; Walid Waked; Thomas Gillon; Andrew White; Christopher
Spock; Debdut Biswas; Todd J. Albert, MD

a - Medtronic Sofamor Danek

Background: Pseudarthrosis continues to be a problem with posterolateral lumbar fusions even using autograft, the
current gold standard. Research continues to investigate the role of potential bone graft alternatives. Recombinant
human bone morphogenetic protein-2 (rhBMP-2) has been shown to be a potent osteoinductive factor.

Purpose: To use an established preclinical pseudoarthrosis repair model to evaluate the ability of two different
formulations of rhBMP-2 to induce fusion versus controls.

Study design: Preclinical rabbit posterolateral lumbar pseudarthrosis repair model.

Methods: Seventy-two New Zealand white rabbits underwent posterolateral lumbar fusion with iliac crest autograft.
Nicotine was continuously administered to all rabbits to induce pseudarthroses. At 5 weeks, the animals were
surgically reexplored. Fused animals were excluded. Pseudarthrosis animals were re-decorticated and randomized to
one of four bone graft materials: no additional graft, autograft, or one of two different formulations of rhBMP-2
(Medtronic); absorbable collagen sponge (ACS) or hydroxyapatite-tricalcium phosphate compression-resistant
matrix (CRM). The ACS formulation (Infuse) contains 1.5 mL of 1.5 mg rhBMP-2 / mL per side. The CRM
formulation (under development) contains 1.5 mL of 2.0 mg rhBMP-2 / mL per side. Nicotine pumps were
exchanged. At 10 weeks, the rabbits were sacrificed and fusions were assessed with manual palpation and histology.
Representative specimens were assessed with radiography or computed tomography.

Results: Four rabbits (5.5%) were lost to complications. Sixty-four (94%) had pseudarthroses on re-exploration and
underwent repair. By manual palpation at 10 weeks, 1 of 16 (6.3%) pseudarthroses that received no graft fused, 5 of
17 (29.4%) pseudarthroses that received autograft fused, 31 of 31 (100%) pseudarthroses that received rhBMP-2
(with either ACS or CRM) fused. Plain radiographs, computed tomography, and histology further characterized the
fusion masses.

Conclusions: Recombinant human bone morphogenetic protein-2 (in both carriers studied) was able to significantly
increase fusion versus controls in this challenging preclinical posterolateral lumbar model.


** The FDA has not cleared a drug and/or medical device described in this presentation (i.e., the drug or medical
device is being discussed in an (off-label use.) For full information refer to page 5
Paper #78

**Hibbs Award Nominee for Best Basic Science Paper

Worst Case Scenario For BMP-2 Mediated Gene Therapy In Posterolateral Fusion

Hyun W. Bae MD (Spine Research Foundation, The Spine Institute); Li Zhao, MD; Ben Pradhan, MD;
Pamela Wong, MD; Linda Kanim, MA; Jeffrey C. Wang, MD; Rick B. Delamarter, MD

Introduction: There are at most 5 studies mentioning safety after >10 years of investigation on cell-mediated BMP-
gene-therapy in orthopaedics. A criticism of cell-mediated gene-therapy is that once the modified cell is placed in
vivo, the production of the desired molecule cannot be controlled. Safety must be critically evaluated before
considering ex vivo or in vivo gene-therapy techniques for elective spinal surgery. The purpose of this study is to
create a worst-case scenario of cell-mediated BMP gene-therapy for posterolateral fusion.

Methods: An immortal cell line (NIH 3t3 mouse fibroblast) was used as the recipient cell. The host animal was an
immunocomprised athymic rat. The vector that was used was a retroviral vector encoding for BMP-2 known for
high infectivity. Twenty-four female adult athymic rnu/rnu rats were utilized. The cDNA of BMP-2 was cloned and
introduced into a retroviral vector. Mouse (NIH-3T3) were separately cultured and transfected with BMP-2 cDNA
via retrovirus. Three separate cell densities 5x106, 10x106, 20x106 of BMP-2-producing cells were absorbed onto
1cm x 0.5cm collagen sponges and placed between the transverse processes of L4-L5. Identical quantities of
fibroblasts producing Lac-Z reporter genes were implanted in a separate control group. Radiographs were performed
biweekly until sacrifice at 6 weeks. Fusion was determined by manual palpation. Histology and micro-CT were
performed.

Results: Three animals in the control group receiving fibroblasts producing a reporter gene developed soft tissue
masses. The tissue masses were graded as fully differentiated fibromas. All animals in the treatment group receiving
fibroblasts producing BMP-2 fused by manual palpation. Five displayed exuberant bone growth. Three animals,
which had exuberant bony growth, developed neurologic weakness and paralysis, and had to be sacrificed early.

Conclusions: This study underscores the fact that production or overproduction of BMP-2 in cell-mediated gene-
therapy may be difficult to regulate, and could lead to detrimental effects in posterolateral fusion.
Paper #79

**Hibbs Award Nominee for Best Basic Science Paper

The Expression of Inflammatory Cytokines Following Acute Spinal Cord Injury: A Human versus Animal
Model Comparison

Brian K. Kwon MD, PhD, FRCSC (ICORD - University of British Columbia); Anthea Stammers; Tiffany
Rice; Steve Casha; John Hurlbert; Scott Paquette; Lise Belanger; Marcel Dvorak; Michael Boyd; Wee Young;
Wolfram Tetzlaff; Charles Fisher, MD, MHSC, FRCSC

Introduction: Inflammation is an important pathophysiologic process in the secondary injury cascade following
spinal cord injury (SCI), and many neuroprotective strategies (eg. methylprednisolone) attempt to attenuate its
damaging effects. Virtually everything known about post-SCI inflammation and the cytokines that mediate it has
been obtained from animal models. However, it is not known how closely inflammation in these rat models
represents the human condition. The purpose of this study was to evaluate the expression of inflammatory cytokines
within the cerebrospinal fluid (CSF) of patients with acute SCI, and to compare this expression to that observed in a
well established animal model.

Methods: A lumbar intrathecal catheter was installed into 10 adult patients with acute SCI, and CSF samples were
obtained at regular intervals for 3-7 days. In parallel investigations, Sprague Dawley rats underwent a thoracic cord
contusion using the Ohio State University Impactor, and the CSF and spinal cords were extracted at similar time
points. The human and rat tissues were evaluated with a BioPlex Protein Array system to assess such cytokines as
IL-1beta, IL-2, IL-4, IL-6, IL-10, GM-CSF, IFN-gamma, and TNF-alpha.

Results: Many inflammatory cytokines were similarly elevated in human and rat samples within 24 hours of injury,
including IL-1beta, IL-2, IL-4, IL-10, TNF-alpha, and IFN-gamma. Most cytokine levels diminished by 72 hours
after injury. The levels of all inflammatory cytokines in non-injured control patients (hip and knee replacement
patients undergoing spinal anesthetics) were either low or too low to be measured.

Conclusion: This study represents the first description of the temporal sequence of inflammatory cytokine
expression in human CSF after spinal cord injury. It provides valuable insight into the similarities and differences
between human SCI and the rat model that attempts to simulate it Such translational research studies help to target
basic science research in clinically relevant directions.
Paper #80

**Hibbs Award Nominee for Best Basic Science Paper

An Intradiscal Injection of Osteogenic Protein-1 Restores the Viscoelastic Properties of Degenerated
Intervertebral Discs in The Rabbit Anular Puncture Model

Howard S. An, MD (Midwest Orthopaedics); Kei Miyamoto; Jesse G. Kim, MS; Nozomu Inoue; Koji Akeda;
Gunnar Andersson, MD; Koichi Masuda, MD

a - Stryker Biotech
e - Stryker Biotech

Introduction: Biological approaches for treating degenerative intervertebral disc (IVD) diseases are of great
interest. An intradiscal injection of osteogenic protein-1 (OP-1) has been shown to be effective in the structural
restoration of the IVD. However, the effect of this approach on the biomechanical properties of the IVD remains
unknown. This study was performed to investigate the effects of OP-1 on the viscoelastic properties of IVDs in the
rabbit anular-puncture disc degeneration model.

Methods: Disc degeneration was established by anulus fibrosus (AF) puncture (18G) at L2/3 and L4/5 (L3/4: non-
punctured controls) in 16 New Zealand White rabbits. Four weeks later each punctured disc received 10 μl of either
5% lactose or OP-1 (100 μg). Disc height was radiographically monitored biweekly. Eight weeks after the injection,
dynamic viscoelastic properties of the IVDs were tested using uniaxial compression at six frequencies. The IVDs
were also analyzed biochemically.

Results: OP-1 injections significantly restored disc height (vs. Lactose, p<0.001). The elastic modulus of the OP-1-
injected IVDs was significantly higher than that in the lactose-injected IVDs at all frequencies (mean: +43%,
p<0.001). The viscous modulus in the OP-1-injected IVDs was significantly higher (0.05, 0.2, 0.5, and 1 Hz [mean:
+55%, p<0.001]) or showed a strong higher tendency in other frequencies. For both moduli, no significant
difference was observed between the OP-1-injected and control IVDs. OP-1 significantly increased the PG content
in the nucleus pulposus (NP) and AF (p<0.001) and the collagen content in the NP. The PG content in the NP and
the collagen and PG contents in the AF showed a positive correlation with the elastic and viscous moduli
(Rho=0.36-0.46).

Discussion: The viscoelastic properties of a degenerated IVD were restored by an injection of OP-1. Correlation
analyses suggest that enhanced anabolic activities resulting from the OP-1 injection may influence the
biomechanical properties of the IVD.




** The FDA has not cleared a drug and/or medical device described in this presentation (i.e., the drug or medical
device is being discussed in an (off-label use.) For full information refer to page 5.
Paper #81

Risk Factors for Surgical Site Infection Following Spinal Surgery

David B. Cohen, MD, MPH (Johns Hopkins University); Lee H. Riley, III, MD; Trish Perl, Xiaoyan Song, Lisa
Maragakis

Purpose: Surgical site infections (SSI's) following spinal surgery results in increased morbidity, mortality, length of
stay and costs. Most previously identified risk factors for SSI are not amenable to interventions to reduce risk. We
sought to identify modifiable risk factos for SSI following spinal surgery that could lead to interventions to reduce
risk.

Methods: ICD-9 codes from administrative databases identified all patients having spinal laminectomy or fusion at
our institution between April 1, 2001 and December 31, 2004. Medical records of patients were reviewed by
hospital infection control to identify cases of SSI using Centers for Disease Control and Prevention (CDC) criteria.
A case-control investigation compared SSI patients to controls randomly selected from a list of patients without SSI
who underwent spinal surgery. One control per case was used and group matching by year was employed.

Results: 104 cases of SSI were identified among 3,894 laminectomy or fusion procedures for an overall infection
rate of 2.67%. Multivariate analysis identified independent risk factors for SSI including prolonged duration of
procedure (odds ratio [OR] 3.0, 95% Confidence interval [CI] 1.1-7.9, P=0.03), American Society of
Anesthesiologists (ASA) score 3 or greater (OR 9.1, 95% CI 3-28, P<0.001).

Conclusions: Prolonged surgical duration, high ASA score, obesity and surgery at the lumbosacral junction were
independent risk factors for SSI following spinal surgery. Avoiding hair removal and administering at least 50%
FiO2 were highly protective against SSI. A prospective evaluation of these interventions is needed to assess their
efficacy for preventing SSI following spinal surgery.
Paper #82

Transpedicluar Decompression in Spinal Tuberculosis – An Adequate Procedure?

Shekhar Bhojraj, MS, FCPS, DOrtho (P D Hinduja National Hospital); Abhay Nene, MS; Sheetal Mohite,
DNB; Raghuprasad Varma, MD; Sameer Desai

Background: With the increasing incidence of spinal Tuberculosis (TB), there has been a renewed interest in the
available surgical options. We study the Trans Pedicular Decompression (TPD), a safe procedure which provides
adequate decompression, without hazards of transcavitatory approaches, permitting use of familiar posterior
implants.

Purpose: To evaluate the decompression potential of TPD and its long term stability.

Study Design: This clinical study is a retrospective analysis of 95 patients in whom TPD was performed for spinal
TB.

Outcome Measures: Frankel grading was used to quantify pre and post operative neurological status.

Methods: We analyzed 95 patients in whom TPD was performed for spinal TB between May 1993 to June 2004 at
our clinic. Indications for surgery were neurological deficit and / or spinal instability.

Follow up period ranged from 2 to 12 years.

Pre and postoperative neurological status (using Frankel’s grading) was documented in each patient.

Results: Spinal rectangle and sub laminar wires were the commonest implants used in adjunct to the TPD. No
stabilization was done in 9 patients. Post op neurological recovery was seen in over 85% of cases. Over half of these
recovered by over 2 Frankel grades. 5 patients showed neurological deterioration post op, which recovered at an
average of 6 months. 2 patients needed a second anterior surgery for progressive neurological deficit after an initial
recovery.
Kyphosis at the affected level did not progress by over 15 degrees in any of the patients. There were no implant
failures requiring re surgery, though proximal and distal junctional kyphosis and asymptomatic screw pull outs were
seen in a total of 18 patients.

Conclusions: TPD is a safe and effective surgical technique to deal with cord compression and instability in
selected patients with spinal TB
Paper #83

**Hibbs Award Nominee for Best Basic Science Paper

Identification of 2 New Genetic Markers for Idiopathic Scoliosis

James W. Ogilvie, MD; John T. Braun, MD; Lesa Nelson; Kenneth Ward, MD

Purpose: While the genetic basis of idiopathic scoliosis (IS) is well established, clear identification of IS markers
has been elusive. We searched for autosomal markers that would correlate with IS that underwent fusion for curves
>40 . The development of a gene-based diagnostic and prognostic test from these results could improve IS
management.

Methods: DNA was collected by blood and/or cheek swab from 500 IS probands and unaffected first degree
relatives whose medical records and x-rays were examined to exclude other diagnoses. Their names were submitted
to a 22 million name data base to establish familial relationships which were determined at >97%. The DNA was
analyzed by capillary electrophoresis for 763 short tandem repeats and gene chip scanning for 116,000 single
nucleotide polymorphisms (SNP). Disease haplotypes were also scanned with a 500K SNP chip to further narrow
the position of the loci.

Summary: Two previously unreported markers were identified with cumulative LOD scores of 7.0 and 7.3 and
highly significant p-values. These markers were present in 95% of those with IS >40 and were not present in
unaffected family members or those with IS

Discusison: Significant differences between AIS patients and controls were identified for several single nucleotide
polymorphisms. Phenotype-genotype correlations (p<0.001) with respect to the degree of curve are underway and
data will be presented. Using information from these studies a genetic test for AIS may be possible that would offer
both diagnostic and prognostic value. Further identification of the genes covered by these markers may lead to the
molecular pathway which results in the development of IS.
Paper #84

**Hibbs Award Nominee for Best Basic Science Paper

Familial Idiopathic Scoliosis: Candidate Regions On Chromosome 10 Within A Subgroup Of Triple Curve
Families

Nancy Hadley Miller, MD (Johns Hopkins University); Coung Vu; Andrew Zorn; Nneka Nzegwu; Cristina
Justice, PhD; Beth Marosy, MA

Introduction: Classification systems in relation to scoliosis have been a hallmark for the clinician in the
development of therapeutic options. The triple curve pattern with three distinct lateral curvatures of approximately
equal severity has been recognized as distinct and, potentially, unique in its presentation. From a large population of
families with FIS, a subpopulation of families with a triple curve pattern was evaluated in order to determine if this
curve pattern is distinct on a genetic level.

Methods: With IRB approval, a sample of families with FIS (202 families, 1198 individuals) were recruited and
underwent a genomic screen. The results were analyzed using a model independent linkage analysis (SIBPAL). A
subgroup of FIS families with at least one member having a triple curve was identified (6 families, 32 individuals).
After initial linkage analyses, the group underwent further finemapping analyses utilizing a battery of SNPs.

Results: Analysis of the data from the genomic screen on the triple curve subgroup revealed significant areas on
chromosome 10 when analyzed qualitatively and quantitatively in either a single-point or multipoint fashion (see
Table).

Conclusion: The utilization of clinical data to discern potential relevance of specific genetic loci in the etiology of
FIS has resulted in an area on chromosome 10 that is significant (p <0.01). The relatively small population of
families within this subgroup coupled with the strength of the data suggests a unique genetic etiological factor
associated with the formation of a triple curve in FIS.

                                   Qualitative                  Quantitative
 SNP/STRP          Mb       Singlepoint Multipoint        Singlepoint Multipoint
  d10s2470      92.354       0.000701      0.004041        0.007814     0.001103
 rs12412496      92.536      0.000345      0.004022        0.011539     0.001092
     rs3939      92.662      0.021507      0.004014        0.127431     0.001088
  rs7913826      93.573      0.069632      0.003996        0.080299     0.001082
 rs10748585      94.669      0.219737      0.003988        0.465099     0.001078
    d10s185     95.178       0.022296      0.003986         0.09002     0.001078
  rs1555870      95.509      0.073489      0.003976        0.004433     0.001065
  rs3781270       95.52      0.206511      0.003975        0.675998     0.001065
    d10s677     95.954       0.000001      0.003956        0.007957     0.001048
  rs1934951      96.788      0.105571      0.003957        0.321312     0.001048
  rs7898759       96.79      0.103244      0.003957        0.017961     0.001048
  rs7086989       97.19      0.009078      0.003956        0.210914     0.001047
  rs2275759      97.614      0.056429      0.003805        0.000551     0.000943
 rs12571884      98.372      0.352497      0.003893        0.062166     0.000914
  rs2282341      98.433      0.241452      0.003902        0.280501     0.000914
 rs10882938      99.201      0.030984      0.003937        0.020489     0.000914
  rs7899632       99.99       0.00001      0.003867        0.020909     0.000907
  rs1336502       100.5      0.235313      0.055132        0.003769     0.004507
  rs4919438     101.996      0.000004      0.012046        0.006746      0.00008
  rs1361265     102.864       0.34942      0.017308        0.275746     0.000147
   rs946327     102.877      0.069376      0.017338        0.005055     0.000147
   d10s1239     103.186      0.015822      0.018038        0.447062     0.000168
Paper #85

Aprotinin Decreases Blood Loss in Complex Adult Spinal Deformity but Increases the Risk of Acute Renal
Failure

Gbolahan O. Okubadejo, MD (Washington University School of Medicine); Keith H. Bridwell, MD;
Lawrence G. Lenke, MD; Jacob Buchowski, MD; David Fang, Christine Baldus, LPN

Introduction: Aprotinin is an antifibrinolytic that reduces blood loss in pediatric neuromuscular patients having
spinal arthrodesis as well as in cardiac patients. This study was designed to examine the efficacy of Aprotinin in
reducing operative blood loss following long spinal arthrodesis in adult spinal deformity patients and to analyze
complications.

Methods: Adult spinal deformity patients undergoing long spinal arthrodesis at one institution between 2001 and
2005 were analyzed. The patients were matched according to age and type of procedure performed. 40 patients
received high-dose Aprotinin (Group A) intraoperatively and 41 patients were matched as controls (Group NA) who
did not receive Aprotinin. Outcome variables included intraoperative blood loss and postoperative complications.

Results: The average age of the Group A patients was 50.9 years and 50.4 years for Group NA. Levels fused were
10.6 for Group A and 9.2 for Group NA. Average osteotomies were 0.35 PSO and 1.98 SPO for Group A and 0.32
PSO and 1.24 SPO for Group NA. Average blood loss for Group A was 710ml and 978ml for Group NA. The
difference was statistically significant with a p< 0.05. Complications seen in Group A included four cases of acute
renal failure (ARF) requiring dialysis and one DVT. In Group NA, there was only one case of acute renal failure
(secondary to gentamicin) and one case of pulmonary embolus. The four Group A patients with ARF were female,
aged 61 – 73 years old, with various comorbidities. All required inpatient hemodialysis, and three averaged two
months of continued outpatient dialysis before resolution of renal compromise. One patient is on chronic dialysis.

Conclusion: In long spinal arthrodesis in complex adult spinal deformity surgery, Aprotinin does reduce
intraoperative blood loss but also substantially increases the risk of acute renal failure.

        Variable              Group A (n = 40)       Group NA(n = 41)             p value
Age                              50.9±13.5              50.4±12.1                 0.8714
EBL                                710ml                  978ml                   0.0373
Cell Saver                         172ml                  267ml                   0.0628
Intraoperative                     293ml                  514ml                   0.0613
transfusion (prbc)
Renal Failure                         4                        1                    NA
DVT/PE                                1                        1                    NA
Statistically Significant with p<0.05


** The FDA has not cleared a drug and/or medical device described in this presentation (i.e., the drug or medical
device is being discussed in an (off-label use.) For full information refer to page 5
Paper #86

Non-Neurological Complications Following Surgery for Adolescent Idiopathic Scoliosis

Rolando M. Puno, MD (Leatherman Spine Institute); Lawrence G. Lenke, MD; B. Stephens Richards, III; Daniel
Sucato, MD, MS; John B. Emans, MD; Mark A. Erickson, MD; Keith H. Bridwell, MD

a - Medtronic Sofamor Danek
d - Medtronic Sofamor Danek
e - Medtronic Sofamor Danek

Purpose: To determine the incidence of non-neurologic complications following surgery for adolescent idiopathic
scoliosis.

Methods: In a prospective cohort of 702 patients who underwent corrective surgery for adolescent idiopathic
scoliosis enrolled in a multi-center database, demographics, surgical history and incidence of non-neurologic
complications were reviewed. Non-neurological complications were divided into peri-operative (first 7 days post-
op), early (within 30 days), and late (after 30 days).

Results: There were 556 females and 147 males with a mean age at the time of surgery of 14.25 years (7-18). 523
had posterior only, 105 anterior only, and 74 combined anterior/posterior procedure. There were 116 complications
in 84 patients giving an overall incidence of 16%. There were 43 peri-operative complications in 41 patients, 52
early complications in 47, and 21 late complications in 17. There were 4 (0.5%) early infections, 25 (3.6%)
operative, 13 (1.7%) respiratory, 3 (0.4%) superior mesenteric syndrome, 3 (0.4%) urinary, and 68 (6.6%) other
complications. Five patients (0.7%) required re-operations: Two early infections and three late implant failures.
Body mass index, cardiac or respiratory disease, previous surgery, pulmonary function, surgical approach, numbers
of levels fused, type of graft, diaphragmatic incision, Lenke type, and region of major curve did not correlate with an
increased incidence of complications. Renal disease and smaller proximal thoracic curves were associated with non-
neurologic complications. Increased blood loss, prolonged posterior operative time and anesthesia time were
associated with higher incidences of non-neurologic complications in the peri-operative period. Prolonged
anesthesia time was also associated with a higher incidence of late non-neurologic complications.

Conclusions: The incidence of non-neurologic postoperative complications following corrective surgery for
adolescent idiopathic scoliosis appears to be low at 16%. The few factors noted to significantly increase the rate of
complications include history of renal disease, increased operative blood loss, prolonged posterior surgery time and
anesthesia time.
Paper #87

Diabetes and Patient Outcomes Following Lumbar Fusion

James A. Browne, MD (Duke University Medical Center); Ricardo Pietrobon; M. Angelyn Bethel; William J.
Richardson, MD

Purpose: Diabetes has been associated with worse outcomes in a variety of orthopaedic procedures. There is
anecdotal evidence that diabetic patients have more complications following lumbar fusion but there is little
evidence to support this conclusion.

Methods: This study analyzed data from the Nationwide Inpatient Sample database for over 163,000 patients
undergoing elective lumbar spine fusion between the years 1988 through 2003. Over 9,000 patients (5.5%) had been
previously diagnosed with diabetes mellitus. Multiple linear and logistic regression models were used to ascertain
whether these patients with diabetes mellitus were more likely than their non-diabetic counterparts to die while in
the hospital, to have in-hospital postoperative complications, to stay longer in the hospital, to have a higher
incidence of non-routine discharge, and to have a higher total cost associated with the procedure.

Results: Bivariate analysis demonstrated that diabetes was significantly associated with postoperative infection,
need for transfusion, pneumonia, in-hospital mortality, and non-routine discharge (p < 0.02). Multivariate regression
analysis, however, suggested no difference in mortality although infection, pneumonia, and non-routine discharge
continued to be highly significant (p < 0.002). The odds ratios of postoperative infection and transfusion were 1.64
(95% CI 1.20 - 2.23) and 1.46 (95% CI 1.36-1.56) respectively. Although the length of stay was not significantly
different, the inflation adjusted cost was over $3000 more in diabetic patients (mean $37,924 versus $40,958).

Conclusions: This large study of inpatients in the United States provides evidence that diabetic patients undergoing
lumbar fusion are at increased risk for postoperative complications, in-hospital mortality, non-routine discharge, and
increased total cost. The database is nationally representative and includes data spread over fifteen years. These
results are important in patient selection and informed consent. Further research is ongoing to determine if
normalization of hyperglycemia can impact the morbidity and mortality of these procedures in patients with
diabetes.
Paper # 88

Complications in Spinal Fusion for Adult Scoliosis. A Report of the Scoliosis Research Society Morbidity and
Mortality Committee.

Jeffrey D. Coe, MD (Community Hospital of Los Gatos); Christopher I. Shaffrey, MD; Vincent Arlet, MD;
Sigurd H. Berven, MD; William F. Donaldson, III, MD; Ram Mudiyam, MD; Jeffrey H. Owen, PhD; Joseph Perra,
MD and Reinhard D. Zeller, MD

Introduction
Scoliosis affecting the adult encompasses primarily both adult idiopathic and “de novo” degenerative deformities.
Although, there are important differences between these scoliosis subtypes in terms of age at time of presentation,
curve type and severity, and surgical treatment strategies; analysis and comparison of these two groups of patients is
worthwhile as they represent the majority of adults undergoing spinal deformity surgery. The purpose of this study
is to determine whether scoliosis subtype (degenerative vs idiopathic) is an independent predictor of complications
and mortality in surgery for adult scoliosis (AS) by an analysis of the SRS M & M database of complications as
submitted by its members.

Materials and Methods
This retrospective study used SRS Morbidity and Mortality data submitted for surgical cases performed from 2003-
05. The null hypotheses are that: 1) the specific scoliosis subtype (degenerative vs idiopathic) has no effect on the
overall rates of recorded complications in adults and 2) the specific scoliosis subtype (degenerative vs idiopathic)
has no effect on the overall rates of recorded mortalities in adults. The classification of scoliosis as adult idiopathic
or degenerative was made by SRS members submitting data.
Of the 69,774 surgical cases submitted by SRS members in the years 2003 through 2005; 16,163 (23.2%) were
performed for the treatment of scoliosis. The 2,852 patients (17.6% of scoliosis cases) identified as having spinal
fusion for AS (age > 20) of either idiopathic origin (n = 1,543, mean age 42.4) or degenerative origin (n = 1,309,
mean age 64.4) comprised the cohort under study. All reported complications were tabulated and totaled for these
procedures with regards to scoliosis subtype, and statistical analysis conducted.

Results
Complications were reported in 394 (13.8%) of the 2,852 patients in this series. One-hundred and ninety (12.3%) of
the 1543 idiopathic scoliosis patients and 204 (15.6%) of the 1309 degenerative scoliosis patients experienced
complications. This difference was statistically significant (p < 0.01). There were seven deaths (0.45%) in the
idiopathic group and seven deaths (0.53%) in the degenerative group (not significant (p = 0.481)). The overall
neurologic complication rate was 1.3% with six documented spinal cord injuries (0.21%) only one of which (0.04%)
was complete.

Conclusions
This study demonstrates that the complication rate for surgery for degenerative AS is significantly higher then
idiopathic AS. The overall mortality rates, however are not significantly different. Limitations of this study include
the difficulty of controlling for co-morbidities, age, curve severity and other potential relevant factors. Nevertheless,
the data in this study may be used to counsel patients with regards to the nature and rates of complications
associated with these diagnostic subtypes of AS in the hands of experienced spinal deformity surgeons.
Paper #89

Comparative Sagittal Plane Correction after Anterior Single Rod Versus Dual Rod Instrumentation in
Idiopathic Thoracolumbar and Lumbar Scoliosis

Kenneth MC Cheung, MD (The University of Hong Kong); Viola Bullmann, MD; Alpaslan Senkoylu; Henry
FH Halm, MD; Y W Wong, MD; Keith DK Luk, MD; Ulf R. Liljenqvist, MD

a - Scoliosis Research Society

Introduction: This study aims to compare the use a single rigid rod system versus a dual rod system in their ability
to maintain sagittal lumbar contour. A consecutive series of patients with AIS of the thoracolumbar and lumbar
spine were reviewed in 2 centres. One centre exclusively used a dual rod system with morsellized bone graft (DR
group: n=47) and the other a single rigid rod (6mm) system with structural rib grafts (SR group: n=48). Sagittal
plane radiologic parameters were evaluated before surgery, immediately post-surgery and at the latest follow-up.

Methods: Mean age at surgery (16 years) and mean curve magnitude (52 ) were comparable between the 2 groups.
Follow up was for a mean of 46.8 and 38.7 months in the SR and DR groups respectively (minimum 24 months).
Spinal fusion rate was 100%. There was no significant change in the lumbar lordosis in both groups before or after
surgery (mean angle SR = 41 : DR = 47 ). For the fusion block lordotic angle, 7/48 cases in the SR group had a loss
of more than 5 (mean 9.7 ). Only 2/47 cases in the DR group lost more than 5 (mean 9.5 ). There was no resultant
change in the sagittal balance in either groups.

Results: This is the first study to directly compare the ability of 2 anterior implant designs to maintain sagital
correction and balance. No loss of correction occured in 85% and 95% of the SR and DR groups respectively. The
SR group has a slightly higher risk of loosing fusion block correction, although this did not translate into sagittal
imbalance.

Conclusion: Based on this study, the authors feel that both methods are valid, and would recommend that single rod
systems be used with structural grafts, while dual rod systems may be particularly useful for large patients.
Paper #90

Surgical Treatment of Lenke Type 3, 4 and 6 Idiopathic Scoliosis curves: Can they be stopped at L3?

Douglas C. Burton, MD (University of Kansas Medical Center); Sue Min Lai, PhD; R. Christopher Glattes,
MD; Marc A. Asher, MD

d – Isola Implants

Purpose: Research suggests extension of scoliosis fusion to L4 predisposes to back pain late. No studies have
examined the incidence of extension of large thoracolumbar curves to L4 since the introduction of pedicle screws in
IS treatment. The purpose of this study is to analyze our results treating large double curves and the effect of anterior
thoracolumbar discectomy in preventing extension to L4.

Methods: 208 patients with IS treated from 1989 through 2002 with the same multiple anchor dual rod posterior
system by one surgeon were reviewed. 28 Lenke type 3, 4, or 6 curves were identified. Eighteen treated with
anterior thoracolumbar discectomy and arthrodesis and sequential posterior instrumentation. Ten treated with
posterior surgery alone. Demographic data, radiographs, and SRS scores were obtained at minimum 24 months
follow-up.

Results: The lower instrumented vertebra was L3 or above in all patients. Anterior/Posterior group: The thoracic
curve averaged 69º preoperatively and corrected to 34º at last follow-up. Thoracolumbar curve averaged 72º and
corrected to 27º at 46 months follow-up. SRS total score was 4.25 at 52 months. 17/18 patients had radiographs and
18/18 completed the SRS-22 at minimum 24 months. There was one empyema. Posterior group: The thoracic curve
averaged 63º preoperatively and corrected to 25º at last follow-up. Thoracolumbar curve averaged 61º and corrected
to 21º at 55 months followup. SRS total score was 4.03 at 73 months. 9/10 patients had radiographs and 9/10
completed the SRS-22 at minimum 24 months. There was one delayed deep wound infection. Curve size, blood loss,
and operative time were greater in the A/P group.

Conclusions: Utilizing lumbar pedicle screws and sequential anterior thoracolumbar/lumbar discectomy (when
needed), no patients with large thoracolumbar curves needed extension to L4. Extension to L4 is unnecessary in the
vast majority of Lenke 3, 4, and 6 curves.
Paper #91

The Reliability of Preoperative Supine Radiographs to Predict the Amount of Curve Flexibility in Adolescent
Idiopathic Scoliosis

Gene Cheh, MD; Lawrence G. Lenke, MD;Yongjung J. Kim; Ronald A. Lehman, Jr., MD; Kathryn Keeler, MD;
Keith H. Bridwell, MD

Purpose: To determine the reliability of supine(SUP)long cassette radiographs as compared to side
bending(SB)films in predicting curve flexibility in cases of adolescent idiopathic scoliosis (AIS). The value of side
bending films is important in classification of AIS, as well as predicting curve flexibility. However, the
reproducibility of side-bending films is highly variable depending on the experience of the technologist and the
willingness of the patient to perform a maximal bend.

Methods: A total of 575 patients with a diagnosis of operative AIS having scoliosis films including standing long
cassette anteroposterior (AP), lateral (LAT), side-bending (left and right) and supine preop films were evaluated. All
curves were classified according to the Lenke classification, along with coronal parameters, Cobb measurements and
sagittal data. Significance was set at p

Results: For GroupI, MT supine films were highly predictive of MT-SB while TL/L supine films were also
predictive of TL/L-SB and upright TL/L.(see Table).An equation was then derived to predict the value of the side-
bending radiographs for each part of the curve (i.e. PT, MT and TL/L). For Group2, MT supine films were highly
predictive of MT-SB and MT upright. MT standing TL/L supine films were highly predictive of TL/L-SB and TL/L
standing. Group1 resulted in a strong statistical ability to predict a nonstructural PT
curve(sensitivity=0.952,PPV=0.864,NPV=0.865) and also a nonstructural TL/L
curve(sensitivity=0.958,PPV=0.916). Similarly, in Group2, we found a strong statistical ability to predict a
nonstructural PT curve (sensitivity=1.00,PPV=0.982,NPV=1.00) and also a nonstructural MT curve
(sensitivity=0.789,specificity=0.842,PPV=0.833,NPV=0.80)

Conclusions: A single preoperative supine X-ray is highly predictive of side-bending radiographs and can be used
as an adjunct to predicting curve type, flexibility and structurality of a curve. This singular, reproducible and non-
effort related radiograph can potentially replace the need for dual side-bending films.
Paper #92

Effects of Alternative Instrumentation Strategies in Adolescent Idiopathic Scoliosis (AIS)

Martin Robitaille; Carl-Eric Aubin, PhD; Hubert Labelle, MD

a - Medtronic Sofamor Danek

Purpose: Surgical instrumentation planning for the correction of scoliosis involves many decisions, especially since
the advent of modern instrumentation systems. Although several clinical publications have attempted to assess the
effects of surgical strategies, no clear consensus exists on an appropriate treatment for optimal clinical outcome in
AIS. The purpose of this study is to evaluate the effects of different instrumentation constructs and fusion levels for
the same scoliotic cases.

Methods: We obtained from 32 experienced Fellows of the SRS and members of the Spinal Deformities Study
Group the detailed preoperative planning (e.g.: selection and location of the implants, rod shape, reduction
maneuvers, etc) for 3 AIS patients with Lenke type 1A, 3B and 5C curves. Different scenarios were individually
simulated using a validated computer model implemented in a “spine surgery simulator” (S3). A cost function that
included six 3D descriptors of the scoliotic deformities was used to quantify the global spinal correction for each
specific strategy.

Results: The resulting Cobb angles varied significantly for the 3 cases (main thoracic: 6-17; 7-30; 16-23; proximal
thoracic: 14-28; 0-37; 6-30 ). The resulting implant-vertebra loading also varied significantly. The variability of
correction remained important (up to 11 of standard deviation) when sub-classifying the results according to the
instrumentation strategies: A- “Pedicle Screws Constructs” [n=21]; B- “Hooks Constructs” [n=2]; C- “Hybrid
Constructs”, [n=7]. But overall, the average correction was better in group A (74%) than in groups B (55%) and C
(68%).

Discussion: This is the first study that compares the effect of instrumentation strategies on the same patients, which
is possible only with such a surgery simulator. A large variability of instrumentation strategies exist within
experienced surgeons and these produce considerably different results. This questions the criteria for optimal
configuration and standards to objectively design the best surgical construct.
Paper #93

Histiocitosis of the Pediatric Spine. Clinical and Radiographic Analysis of Seventy-one Vertebral Lesions

Rodrigo Remondino, MD; Carlos A. Tello, MD; Ernesto Bersusky, MD; Alejandra

Objective: To report clinical and radiographic findings, to evaluate the results of modern treatment, complications
and long term follow up.

Method: Forty-one patients with spinal histiocytosis with biopsy proven were studied.
A follow up of 7.5 years (2.7 to 15.7 years).The age at the diagnosis was 5.7 years (0.6 to 12.5 years). The vertebral
body was the most commonly affected 69%, posterior arch 8.5% and both 22.5%. Eighteen patients had osseous
lesions. Vertebral body collapse was measured by Washington University and Children´s Hospital of Philadelphia
classification.

Results: The most common symptom was pain (87 %). Twenty eight patients had spinal deformity associated with
lesions site, 22 kyphosis with mean angular value 17 (12 to 38 ), 2 patients lordosis and 4 patients scoliosis with
mean angular value 12 (10 to 22 ). None of the forty one patients (100%) had evidence of persistent or active
disease through 5.5 years follow up. From seventy one involved vertebrae, 34 had symmetric collapse (A), 31
symmetric collapse (B); The radigraphic classification was 35% collapse type II B, 24% type I A, 24% type II A,
8% type I B and 8 % type III. 31 patients had medical treatment: 9 patients combination of chemotherapy and
corticoids; 6 patients; 3 patients chemotherapy; 8 patients radiation therapy; 2 patients radiation plus corticoids, 2
patients chemotherapy, radiation and corticoids and 1 patients chemotherapy plus radiotherapy. Only three patients
had indication for surgery due to neurologic symptoms and seven patients just followed by radiographic and
observation. Fifteen patients wore cast and brace.

Conclusions: We had high incidente of cervical lesions associated with neurologic cervical symptoms 71%. The
symmetric collapsed were the most common presentation. All the spinal deformity had good resolution and none
had progressions. The surgery is usually not indicated.
Paper #94

Surgery in Spinal Metastasis – Was it Worth it?

Shekhar Bhojraj, MS, FCPS, DOrtho (P D Hinduja National Hospital); Abhay Nene, MS; Sheetal Mohite,
DNB; Raghuprasad Varma, MD

Aims: To evaluate results of surgical treatment in symptomatic spinal metastasis, in terms of quality of life, and risk
- benefit ratio.

Materials and Methods: We reviewed 54 surgical interventions in 48 cases of symptomatic spinal metastasis
operated between May 1993 and May 2002. Outcome was based on analysis of hospital medical records and
telephonic interviews. Assessment of results was made at an average of 3 1/2 years post op. All patients had spinal
instability, and 28 cases presented with neurological deficit of varying grades. 17 underwent pre operative digital
subtraction angiography and embolisation was carried out in 10. Anterior surgery was performed in 16, Posterior
surgery in 34 patients and combined approach was used in 4. 5 patients underwent a repeat surgical intervention
after a good pain free and functional period. The average blood loss was 700 cc .The average duration of surgery
was 4 hrs.

Results: Mean post operative survival was 11 months. This survival statistic makes a strong case for surgery in
these patients. Over 80 % of our 48 patients were satisfied with pain relief. This statistic was based on patients / next
of kin’s response to direct questions. Neurological recovery was observed in 30 % of the 28 cases with pre operative
neurological deficit. There were no major anaesthetic complications in any of the patients. One patient had a surgical
complication in the form of a pharyngeal fistula following anterior cervical spine surgery.

Conclusions: Surgical intervention in metastatic disease of the spine has definite advantages of pain relief and
return to function in a select group of patients. A fairly long life expectancy in most cases with spinal mets, makes a
case for intervention to improve the quality of remaining life.
Paper #95

Solitary Plasmacytomasof the Spine: Management & Outcomes

Abhay Nene, MS; Shekhar Bhojraj, MS, FCPS, DOrtho; Sheetal Mohite DNB; Raghuprasad Varma, MD

Aim: To evaluate the results of operated patients of solitary plasmacytomas of spine and to assess their long term
follow up i.e. conversion to multiple myeloma.

Material & Methods: We reviewed 13 patients of solitary plasmacytoma of spine who were operated upon at our
centre between 1990 to 2000. There were 9 males and 4 females, with average age 46 years (33 – 63 years range).
The tumor was confined to thoracic spine in 7 cases, lumbar in 5 cases and 1 case of Cervical spine. All presented
with local pain. 5 of the 13 patients had neurological deficit at presentation. 4 of the 13 patients had radicular pains.
Minimum follow up was 5 years. Treatment consisted of surgery followed by radiotherapy and chemotherapy.
Surgery was performed anteriorly in 5 cases, posteriorly in 7 cases and a single stage posterior+anterior procedure
was done in 1 case, based on the location of the tumor. Pre-operatively digital subtraction angiography was
performed in 8 patients of which 6 underwent succ essful embolization. Average blood loss was 850 cc and
operative time was 4½ hours.

Result: All 5 patients with pre op neurological deficits, showed post op recovery and all patients had significant
relief of back / neck pain. At last follow up (minimum 5 years), 5 patients had converted to multiple myeloma (at an
average of 4 years post op) 3 remained soitary, 3 had died and 2 were untraceable.

Conclusion: Solitary Plasmacytomas of the spine respond well to surgery, with appropriate back up therapy.
Neurological deficit, instability, uncertain diagnosis remain the indications for surgery. Long follow up is necessary
as a fair number convert to multiple myeloma.
Paper #96

Surgical Resection of Aneurysmal Bone Cyst of the Spine

Hossam Salah MD, FRCS (Eng) (Cairo University); Youssry El-Hawary, MD

Introduction: It is estimated that 11 – 24% of aneurysmal bone cysts localize in the spine. Local recurrence
following surgical treatment has been reported to range between 20 – 70% in different series. We report our
experience in the surgical management of these lesions of the spine. There were 12 patients; 7 males and 5 females.
Age at time of surgery ranged between 4 and 18 years. All patients presented with axial pain, and 7 (58%) with
radicular pain. Four (33%) patients had a neurological deficit, four (33%) presented with spinal deformity and three
(25%) had a palpable mass. Nine (75%) patients had previous surgeries (a total of 17 operations).

Method: Complete intralesional surgical resection was performed in all patients. No adjuvant therapy was
performed in this series. Resection required sequential anterior and posterior surgery in 9 patients and posterior
surgery only in three. Spinal reconstruction and stabilization was performed with a variety of methods depending
upon the location of the lesion, its extent within the spine and the age of the patient.

Results: Follow up period ranged 28 – 63 months. All patients reported improvement in their axial and radicular
pain, three (75%) of those with a preoperative neurological deficit showed neurological recovery and one patient
remained unchanged. At their latest follow-up, all patients showed evidence of radiological fusion, with no local
recurrence detected.

Conclusion: Total intralesional resection of ABC lesions of the spine is successful in managing these oftenly
aggressive lesions. This series demonstrates the success of surgery in eradicating these lesions when thorough and
complete resection is performed.




     32 months
     postop
Paper #97

Long-Term Outcomes of High Grade Pediatric Spondylolisthesis Treated with Posterolateral Fusion and
Fibular Dowel Grafting

Christopher G. Furey, MD (Case Western Reserve University); George H. Thompson, MD; Michael Cluck;
Henry H. Bohlman, MD

Introduction: Twenty-two pediatric patients with high grade spondylolisthesis underwent posterior decompression
and posterolateral fusion and fibular dowel placement without aggressive attempt at deformity correction.

Method: Average age was 13.5 years (range 11-17 years). All patients had both back and bilateral leg pain. 5
patients had Meyerding grade III spondylolisthesis, 12 had grade IV, and 5 had spondyloptosis. No patient had
undergone prior surgery. All patients had posterolateral fusion with iliac crest grafting; 8 patients had pedicle screw
instrumentation. Allograft fibular dowels were placed via a posterior approach from the sacrum to L5. Average
follow-up was 8.6 years (range 3-17 years).

Results: Clinical outcome was assessed with a specific questionnaire addressing relief of back and leg pain,
improvement in quality of life, and achievement of pre-operative expectations. Parameters measured were
Meyerding grade, slip angle, sacral inclination, lumbar lordosis, and pelvic incidence. Radiographs evaluated
posterolateral fusion mass, integrity of the fibular dowel, and hardware failure if present. 86% of patients had good
or excellent relief of back pain, while 91% had good or excellent relief of leg pain. 95% of patients reported
improvement in quality of life and 91% felt their pre-operative expectations had been achieved. 91% of patients had
solid posterolateral fusion by 6 months. Fracture of a fibular dowel occurred in one case. Hardware failure occurred
in one case. Pedicle screw instrumentation did not affect clinical or radiographic outcome. 3 patients (14%) required
further surgery; two with a symptomatic pseudarthrosis underwent supplemental posterolateral fusion and a third
had elective removal of painful, loose hardware.

Conclusion: Transient L5 neuropraxia occurred in 4 cases but no persistent neurologic deficits were noted. Lumbar
lordosis improved an average of 6 degrees. Slip angle, sacral inclination, slip grade and pelvic incidence were not
found to significantly affect clinical outcome.
Paper #98

Clinical and Radiological Outcome of Pedicular Transvertebral Screw Fixation of the Lumbosacral Spine in
Spondylolisthesis vs. Unilateral Transforaminal Lumbar Interbody Fusion (TLIF) with Harms cages

Juan Carlos Rodriguez Olaverri, MD, PhD (Hospital Miguel Servet); Javier Vicente, MD; Javier Rodriguez,
MD; Antonio Tabuenca; Antonio Loste, MD; Enrique Suñen; Jesus Burgos, MD; Eduardo Hevia, MD; Gabriel
Piza Vallespir; Pedro Domenech

Purpose: The goals were to examine the outcomes and perioperative complications of the two techniques in the
treatment of High-grade spondylolisthesis

Material and Methods: Forty patients divided in two groups A, TILIF 360 fusion, B transacral screws. The average
age at the time of surgery was 33 years (range, 19-48 years), and the average follow-up period was 35 months
(range, 24-48 months). Before surgery, twenty patients had low back pain, ten patients had radiating leg pain, and
ten patients had hamstring tightness. The average grade of spondylolisthesis by Meyerding grading was 3.6 (range,
3-5). An SRS outcome score was also obtained on all patients to evaluate postoperative outcome, in terms of pain
control, self-image perception, and return to function.

Results: Group A.100% fusion, (based on oblique radiographs showing lateral bridging bone masses and a CT). The
slip angle, as measured from the inferior end plate of L5, improved from 38.6 (range, 24 -78 ) before surgery to
23.8 (range, 12-38 ) after surgery. Group B 19 patients evidenced solid fusion by the 6-month follow-up. The slip
angle, improved from 38.2 (range, 22-78 ) before surgery to 23 (range, 9-36 ) after surgery there was no significant
improvement in the percentage slip or the sacral inclination in any of the groups. Complications A: seven incidental
durotomies and three infections B: one dural tear, one pseudoarthrosis, two superficial infections one broken
transvertebral screw. There were no neurologic complications in any of the groups The SRS outcome instrument
demonstrated good postoperative pain control, function, self-image, and satisfaction in both groups.

Conclusions: No differences in radiological and clinical outcome were found, so both are useful in
spondylolisthesis treatment. The only differences were that the higher the grade the difficulty of the technique
increases in the TILIF group and decreases in the Transacral group.
Paper #99

Longitudinal Retrospective Preliminary Study To Determine The Incidence And Grade Of Listhesis In
Children With Spina Bifida.

Carlos Villanueva, MD, PhD (Hospital Del Valle De Hebron - Barcelona); Judith Sánchez-Raya, Almudena
Crespo, Natalia Toneu, Esther Pagès, Jordi Iborra, Ampar Cuxart

Background: The absence of important posterior elements in myelomeningocele (MMC) seems to justify a higher
prevalence of spondylolisthesis among these patients regarding the normal population. The aim of this study was to
analyze the prevalence and the degree of slippage of spondylolisthesis in myelomeningocele patients.

Patients and Methods: 183 patients with myelomeningocele were randomly chosen from a roster of >500 patients
with myelomeningocele followed at a multidisciplinary spina bifida unit in a tertiary university public hospital. A
cross-sectional study was done collecting data from patient records and X-rays archives. X-rays measurements of
sacral slope and grade of listhesis were standardized with AutoCad System. To study relationships among the
variables, the Chi-squared, ANOVA tests were applied.

Results: The mean age of this series was 23,73 years (range 2-53). 96 were male and 87 were female. 76.4% of
patients had mid-lumbar, low-lumbar or sacral neurological levels. 23.5% had spondylolisthesis. The mean slippage
was 19.86% (range 6.79-44.41), being 71,9% grade I and the remaining 27.9% grade II. The more frequent level for
slippage was L5-S1. All the patients with spondylolisthesis were ambulators, except one adult that currently had lost
her ambulation capacity. The presence of spondylolisthesis were statistically related with ambulation (p=0.003).
ambulatory type (p=0.007), functional ambulation type (p=0.004), scoliosis (p=0.001), lumbar hyperlordosis
(p=0.001), age (p=0.039) and age onset of ambulation (p=0.043). In the multivariable analysis were determinant: the
hyperlordosis (p=0.000; IC 95% 0.127-0.415), type of gait (p=0.005; IC 95% -0.121/-0.021) and age (p=0.016;IC
95% -0.014/-0.001).

Conclusions: Prevalence of spondylolisthesis in MMC is greater than in normal population (23.5% vs 5.8%).
Ambulation and hyperlordosis were related with the presence of spondylolisthesis.
Paper #100

Classification Of High Grade Spondylolisthesis

M. Timothy Hresko (Children’s Hospital Boston)

a - Spinal Deformtiy Study Group
a - Medtronic Sofamor Danek

Purpose: To analyze the sagittal spinopelvic alignment in patients with high-grade spondylolisthesis and identify
sub groups that may require reduction to restore sagittal balance.

Methods: 133 subjects, mean age 17, with high-grade spondylolisthesis were identified from a multiple center data
base containing standing lateral radiographs of patients with developmental spondylolysis/spondylolisthesis. The
films were digitized and custom software determined the sagittal alignment of the spine and pelvis. K-means cluster
analysis was performed to identify two natural groups based on the pelvic tilt and sacral slope. Correlations were
determined for lumbosacral angle (LSA), lumbar lordosis (LL), pelvic incidence (PI), L5 incidence (L5I), and
thoracic kyphosis (TK) and groups were compared by paired T test.

Results: Cluster analysis identified two distinct groups: reverted pelvis with vertical sacrum had high PT (mean
36.5) / low SS (mean 40.3) and a balanced pelvic version group with low PT/ high SS (mean 21.3 /59.9). The
retroverted pelvis with vertical sacrum group had significantly greater PI, L5I, and LSA and less TK than the
balanced pelvic group.
n PI L5I LSA LL TK
Retroverted pelvis 71 76.8 77.1 29.0 75.2 33.7
Balanced pelvis 62 81.2 52.5 9.4 73.4 42.0
P value .038 <.001

Conclusion: Analysis of sagittal alignment of patient with high grade spondylolisthesis revealed 2 distinct groups.
Those with a high PT/low SS had a retroverted pelvis with vertical sacrum and highly significant greater LSA and
L5I, and significant less TK than the group with balanced pelvic version.

Significance: High-grade spondylolisthesis occurs in patients with two distinct orientations of sagittal sacral
alignment. The mechanical strain on the spinopelvic junction will differ in each group. Treatment strategies for
high-grade spondylolisthesis may differ for each group; reduction techniques might be considered in the retroverted
pelvis group of patients with high-grade spondylolisthesis.

                                   n          PI        L5I         LSA          LL         TK
                  Retroverted      71         76.8      77.1        29.0         75.2       33.7
                  pelvis
                  Balanced         62         81.2      52.5        9.4          73.4       42.0
                  pelvis
                  P value                     .038      <. 00001    <. 001       NS         <. 001

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:40
posted:5/7/2011
language:English
pages:106