SRS_When_to_operate

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					            When to operate on
          Adult Scoliosis patients
           and when to say ‘No’



Frank Schwab, MD
Jean-Pierre Farcy, MD
                                         NYU-Hospital for Joint Diseases
New York University School of Medicine   Department of Orthopaedic Surgery
What is Adult Scoliosis?
          What is Adult Scoliosis?

• Coronal plane deformity
• Sagittal plane deformity   Adolescent deformity in an adult
• Imbalance/malalignment           AISA
   – Focal
   – Regional                De-novo deformity…of aging
   – Global                        DDS
                   Scoliosis
Prevalence
  – AIS      2-4% of screened pediatric population

  – Adult >60% of screened elderly population#



 Demographics :
 Life expectancy, birth rates….
 Significant growth of aging population segment

                          # Schwab et al. SPINE 2005 May 1;30(9):1082-5
        Adolescent Idiopathic Scoliosis:
              surgical treatment

                 Curve severity               Skeletal maturity
                 • Cobb angle                        • Risser sign
                 • progression



                          Curve pattern
Classification               • apex
• Lenke                          • distribution          Surgical
• King                           • sagittal              strategy
                                 • overhang
Adult Scoliosis Scoliosis:
  treatment approach
    Curve severity
    • Cobb angle
    • progression

    Skeletal maturity      Classification
           • Risser sign         ?

    Cosmesis
                           PT
    Pain                   Pain Mgmt
                           Bracing
    Disability             Surgery
            The aging spine

Spine      30’s          50’s
skeletal   disc degen.   facet DJD            Stable spine
maturity   MRI changes   disc collapse        ankylosis




                                 Unfavorable degeneration

                             stenosis    spondylo deformity


                                  Adult Scoliosis
                   Progressive
                   collapse




Stable ankylosis
      Adult Scoliosis / Deformity
What are the disability / pain generators ?

       98 patients (Schwab,Farcy. SPINE 2004)
          • adult scoliosis, all levels
          • SF-36
          • radiographic-clinical analysis




      325 patients (Schwab, Farcy. SDSG. SRS 2004)
          • thoracolumbar/lumbar scoliosis
          • SRS instrument, ODI
          • radiographic-clinical correlation
        Adult Scoliosis : Clinical impact

• Significant                    • Not significant
   – Spondylolisthesis
   – Lateral Subluxation             – Coronal Cobb
   – Lumbar lordosis                 – Age
   – Thoracolumbar                   – Adolescent vs. de-novo
     alignment                         degenerative scoliosis
   – Apical level
   – Sagittal Balance (SVA)


       Statistically significant: SRS-22, ODI, SF-12/36
Adult Scoliosis: the disability / pain generators

   plain radiographs

      •   Apical level of deformity (lumbar dominant)
      •   Lumbar lordosis T12-S1
      •   Maximal intervertebral subluxation (frontal/sagittal)
      •   Sagittal balance (PlC7-S1 offset)



     Selected for high clinical impact: SRS, ODI, SF-36

                             (excluding fractures or other pathologies…)
              Classification of Adult Deformity
                                       Schwab et al. SPINE 2006

Type      I           thoracic-only curve (no other curves)
         II           upper thoracic major, apex T4-8
         III          lower thoracic major, apex T9-T10
         IV           thoracolumbar major curve, apex T11-L1
         V            lumbar major curve, apex L2-L4
         Type K       no scoli (<100), principal sagittal plane deformity

Lumbar Lordosis       A         marked lordosis >400
Modifier              B         moderate lordosis 0-400
                      C         no lordosis present Cobb >00

Subluxation           0         no intervertebral subluxation any level
Modifier              +         maximal measured subluxation 1-6mm
                      ++        maximal subluxation >7mm

Sagittal Balance      N         normal, <4cm positive SVA
Modifier              P         positive, 4-9.5cm
                      VP        very positive, >9.5cm
                   Adult Scoliosis
            947 patients: (86% female, 14% male)
            Average age 48 years (SD 18)
            Coronal Cobb mean 460 (SD 19)

                                                ODI                  SRS
                                                Oswestry     SRS Function     SRS Pain
                                              Mean      SD   Mean     SD    Mean     SD
                                                p = 0.002      p < 0.001      p = 0.007
 Lordosis       Lordosis modifier A (< -40)    27       19    69       17    65       20

                Lordosis modifier C ( >= 0)    37      16     57     15      56      17

                                                Oswestry     SRS Function     SRS Pain
                                               Mean    SD    Mean     SD    Mean     SD
                                                p < 0.001      p < 0.001      p < 0.001
Subluxation       Subluxation Modifier 0        27      20    68      18     64      20

                 Subluxation Modifier ++        34      18    63      16     58      19


  Global
  Balance
           Adult Scoliosis / Deformity
Thus….deformity = disability ?


Yes, certain aspects …
                                         Coronal/Sagittal

         Focal: subluxation
         Regional: loss of lordosis
         Global: sagittal imbalance
                                         Sagittal plane


              … Not coronal Cobb angle
          Adult Scoliosis / Deformity: Why surgery ?


 Young adult: AISA                   Curve progression likely
                                        – Disability later (potential)
                                        – More difficult to treat later
>500 thoracic                               • Depending upon age
>300 lumbar (progressive)               – Surgical risks greater later

Progression with disability
                                     Cosmetic concerns




  Weinstein S,. Spine 24(24), 1999
        Adult Scoliosis / Deformity: Why surgery ?



     Older Adult:            Pain unacceptable
    AISA = DDS
                             Disability unacceptable
Pain/disability
  failed conservative care   Risk/Benefit ratio
                                   - favorable
              Adult Scoliosis / Deformity


If the justification for surgery is acceptable….

        …..when is it really reasonable to operate




                              ?
Don’t do it                                          Sure success
       Adult Scoliosis / Deformity

Not a candidate for surgery:

  –   young AISA…no disability, mild/mod curve, happy
  –   patient who does not want surgery
  –   patient is unlikely to survive surgery
  –   patient does not understand risk/benefit
       • unrealistic expectations
  – planned operation is not reasonable
       • experience, team, environment
           Adult Scoliosis / Deformity
Possibly Excellent candidate for surgery:

   – young AISA…progressive, severe curve (>700)

   DDS or AISA older adult:
   Perfectly isolated pain generator, failed extensive non-operative care
       • Well informed, wishes to pursue operative care
       • Excellent health
       • Realistic expectations, highly motivated
   – team has abundant experience only excellent results with planned
     intervention
        Adult Scoliosis / Deformity
The common cases:

•   Patient might consider surgery with certain assurances
•   Health is acceptable (not ideal),
•   Pain generators present (there are several),
•   Non-operative care tried (variable participation and response),
•   Expectations are overall rather realistic.
•   The surgeon comfortable with intervention
                                                          ?
When to operate on Adult Scoliosis patients and when to say No




How can we select the best patients for surgery ?
(and how to optimize the chances of a successful outcome)




     • non-operative care vs. surgery
     • If surgery…which strategy/approach

         – Specific treatment algorithms lacking
         – few studies to guide us….where is the data ?
Adult Scoliosis: Thoracolumbar / Lumbar Deformity


   Who gets surgery…and what type ?                                     (n=809)


Operative rates
   – Lordosis
       • Lost lordosis vs. good lordosis (B vs. A) 51% vs 37%, p<0.05

   – Subluxation modifier
       • Marked subluxation vs. none (++ vs. 0) 52% vs. 36 %, p<0.05

   – Sagittal Balance
       • Well balanced versus marked imbalance (N vs. VP) 39% vs.59%, p<0.05
Adult Scoliosis: Thoracolumbar / Lumbar Deformity

       Who gets surgery…and what type ?

Use of osteotomies
         Lordosis >400 lordo vs. no lordo : 25% vs. 50% p=0.01
         Sagittal balance no imbalance vs. >9.5cm : 25% vs. 53% p=0.01

Surgical Approach
         Anterior only: no lost lordosis, no subluxation
         Circumferential: some lost lordosis, marked subluxation
         Posterior only: marked loss of lordosis, marked sagittal imbalance


Fusion to sacrum
         Lordosis           Loss of lordosis more likely fusion to sacrum (p = .041)
         Sagittal Balance   increasing positive balance: more fixation to sacrum.
                            (<4cm: 59%, 4-9.5cm: 80%, >9.5cm: 88%) (all p<0.05)
Adult Scoliosis: Thoracolumbar / Lumbar Deformity

        How about surgical outcomes ?


    •   111patients 1-year follow up
    •   45 patients 2-year follow up
    •   Adult Thoracolumbar / Lumbar major curves
    •   Surgical treatment, complete data
        – Full-length standing x-rays (0,12,24 months)
        – SRS, ODI, SF-12
2-year Surgical outcome: Lordosis modifier
   Lumbar Lordosis                               A          marked lordosis >400
   Modifier                                      B          moderate lordosis 0-400
                                                 C          no lordosis present Cobb >00

                     Mean SRS Total Score at Baseline and Two Years by Lordosis
                                              Modifier

                80



                70



                60



                50
   Mean Score




                                                                                  Marked Lordosis
                40                                                                Moderate Lordosis
                                                                                  No Lordosis

                30



                20



                10



                0
                           Baseline                         Two Year
                                       Measurement Period




   Lordosis modifier ‘C’…most improved
2-year Surgical outcome: sagittal balance (surgical approach)
       Sagittal Balance                                  N              normal, <4cm positive SVA
       Modifier                                          P              positive, 4-9.5cm
                                                         VP             very positive, >9.5cm

                            Mean Oswestry Disability Index at Baseline and Two Years by Sagittal
                                        Balance Modifier and Surgical Approach

                     60




                     50




                     40
                                                                                               <40 Anterior
                                                                                               <40 Circum
        Mean Score




                                                                                               <40 Posterior
                     30                                                                        40 to 95 Circum
                                                                                               40 to 95 Circum
                                                                                               96+ Circum
                                                                                                    posterior
                                                                                               96+ Circum
                     20




                     10




                     0
                                      Baseline                            Two Year
                                                   Measurement Period




       N with anterior approach did worst (VP posterior-only also not so good)
                          P, VP did best with circumferential fusion
2-year Surgical outcome: sagittal balance (fixation to sacrum)
                          Mean SRS Total Score at Baseline and Two Years by Sagittal Balance
                                         Modifier and Fixation to the Sacrum

                     90


                     80


                     70


                     60
                                                                                           <40 Without
        Mean Score




                     50                                                                    <40 With
                                                                                           40 to 95 Without
                                                                                           40 to 95 With
                     40                                                                    96+ Without
                                                                                           96+ With
                     30


                     20


                     10


                     0
                                    Baseline                         Two Year
                                                Measurement Period




       VP without fixation to sacrum got worse
       P and VP did best with fixation to sacrum (no difference for N)
2-year Surgical outcome: osteotomy or not ?
                  Mean SF-12v2 PCS at Baseline and Two Years by Osteotomy

             50


             45


             40


             35


             30
Mean Score




                                                                            No Osteotomy
             25
                                                                            Osteotomy

             20


             15


             10


             5


             0
                       Baseline                          Two Year
                                    Measurement Period




     Patients who had osteotomy did better !
Baseline to Two-Year Changes: Significant Interaction

 ODI / SRS Total Score by lordosis
       • patients with no lordosis (C) greatest improvement,
       • Patients with marked lordosis (A) little or no improvement


ODI / SRS Total Score by sagittal balance by surgical approach
         • well balanced least disabled, fused short of sacrum did best
         • very imbalance (VP) most disabled and worse off if not fused to sacrum


SF-12v2 / SRS Total Score by Subluxation
          • significant subluxation (++,+) more improvement than no subluxation


SF-12v2 PCS / SRS Total score by Osteotomy Status
          • patients with osteotomy had lower baseline scores
          •At 2 years f/u, patients with an osteotomy had higher scores
Adult Scoliosis: Thoracolumbar / Lumbar Deformity

                       Follow-up data

 • When is improvement clinically significant ?

    – Set a bar of 10-point increase in SRS score
       • From 100pt. Scale


    – Assumption of patient perceived improvement
       • Minimal Clinically Important Difference
           – Berven et al.
                             Minimum 10 point SRS instrument improvement
                                   Met Ten-Point SRS Improvement Criterion by Year and Gender
                                                                         100%          100%
                            100%


                            90%


                            80%

                                                       69%
                            70%
Percent Meeting Criterion




                                        62%
                            60%

                                                                                                One Year
                            50%
                                                                                                Two Year

                            40%


                            30%


                            20%


                            10%


                             0%
                                              Female                            Male
                                                             Gender
 Minimum 10 point SRS instrument improvement
                                    Met Ten-Point SRS Improvement Criterion by Year and Lordosis
                                                             Modifier
                                                                                     100%        100%
                             100%


                             90%


                             80%                                         78%
 Percent Meeting Criterion




                             70%                             67%
                                                  61%
                             60%      57%

                                                                                                             One Year
                             50%
                                                                                                             Two Year

                             40%


                             30%


                             20%


                             10%


                              0%
                                     A - marked lordosis   B - moderate lordosis   C - No lordosis present
                                                           Lordosis Modifier




Loss of lumbar lordosis…greater likelihood of clinical success
           Minimum 10 point SRS instrument improvement
                                    Met Ten-Point SRS Improvement Criterion by Year and Sagittal
                                                         Balance Modifier

                             100%


                             90%                                                              88%


                             80%
                                                              73%       73%
 Percent Meeting Criterion




                             70%
                                               64%                                  63%
                                      60%
                             60%

                                                                                                     One Year
                             50%
                                                                                                     Two Year

                             40%


                             30%


                             20%


                             10%


                              0%
                                        Under 40                 40 to 95           96 and Greater
                                                        Sagittal Balance Modifier



At 2-yr follow up:
greater imbalance patients more likely to have successful outcome
    Minimum 10 point SRS instrument improvement
                                       Met Ten-Point SRS Improvement Criterion by Year and Osteotomy

                                100%


                                90%

                                                                                                 80%
                                80%
                                                                                  73%

                                70%
    Percent Meeting Criterion




                                                             66%

                                              59%
                                60%

                                                                                                        One Year
                                50%
                                                                                                        Two Year

                                40%


                                30%


                                20%


                                10%


                                 0%
                                             No Osteotomy Performed               Osteotomy Performed
                                                                      Osteotomy




Patients having osteotomies more likely to have successful outcome
    Minimum 10 point SRS instrument improvement
                                         Met Ten-Point SRS Improvement Criterion by Year and Baseline SF-12
                                                                      PCS

                                  100%
                                                  92%
                                  90%
                                            83%

                                  80%                                78%
      Percent Meeting Criterion




                                  70%                        67%


                                  60%                                                58%    58%


                                                                                                                     One Year
                                  50%
                                                                                                     44%     44%     Two Year

                                  40%


                                  30%


                                  20%


                                  10%


                                   0%
                                             Under 25        25 to Under 35         35 to Under 45   45 and Higher
                                                                      Baseline SF-12 PCS




Patients with lower baseline scores more likely to achieve significant improvement
When to operate on Adult Scoliosis patients and when to say No




    How can we select the best patients for surgery ?
           (and how to optimize the chances of a successful outcome)




    Can we predict who will have successful surgery ?
              Predictive Models

–   Gender                 –   Surgical Approach
                           –   Osteotomy
–   Age
                           –   Fixation to Sacrum
–   Apical Modifier
                           –   SF-12v2 Physical Component Summary
–   Lordosis Modifier
                           –   SF-12v2 Mental Component Summary
–   Subluxation Modifier   –   SRS Total Score
–   Sagittal Balance       –   Oswestry Disability Index




                                      Outcome ?
Models to predict Clinical Improvement with Surgery
                          Strength of Predictive Models
    Outcome Score          % Correct          Area Under ROC       % of Surgical Cases
     (meeting the       Classification by   Curve (.80 and above     Failing to Meet
    MCID threshold)         Model            is considered good          Criterion
                                                discrimination)

  SRS Pain                  81.1%                  .864                  39.5%


  SRS Appearance            75.4%                  .838                  33.3%



  SRS                       78.1%                  .845                  53.5%
  Pain and Appearance

  SF-12v2 PCS               77.9%                  .862                  47.6%
         Follow-up data: Conclusions
 The winners
     –   Greater disability at start (SRS, ODI, SF-12)
     –   Male
     –   Subluxation >6mm
     –   Lost lumbar lordosis <400
     –   Osteotomy



Who benefits least
      • minimal baseline disability (SRS, ODI, SF-12)
         • No subluxation, no marked sagittal imbalance
         • Good lordosis, >400
         • Lack of osteotomy
When to operate on Adult Scoliosis patients and when to say No




   How can we select the best patients for surgery ?
         (and how to optimize the chances of a successful outcome)




                                                        apex
                      Regional deformity
SRS, ODI, SF-12                           Global sagittal balance
                          Surgical approach
          gender                                osteotomy
                    Focal deformity
Adult Scoliosis / Deformity: next steps




                  Refine Classification

    +             Predictive outcomes model

SRS
ODI
SF-12/36            Treatment Algorithm
Thank you….

				
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