Role of intraoperative angiography in the surgical treatment of by smx43008


									                                                                                                           J Neurosurg 88:441–448, 1998

                      Role of intraoperative angiography in the surgical treatment
                      of cerebral aneurysms

                      TROY D. PAYNER, M.D., TERRY G. HORNER, M.D., THOMAS J. LEIPZIG, M.D.,
                      JOHN A. SCOTT, M.D., RICHARD L. GILMOR, M.D., AND ANDREW J. DENARDO, M.D.
                      Indianapolis Neurosurgical Group, Indianapolis, Indiana; and Radiology Specialists of Indiana,
                      Indianapolis, Indiana

                         The benefit of using intraoperative angiography (IA) during aneurysm surgery is still uncertain.
                         Object. In this prospective study, the authors evaluate the radiographically demonstrated success of surgical treat-
                      ment in 151 consecutive patients harboring 173 aneurysms who selectively underwent IA examination. The authors
                      also assess the frequency with which IA led to repositioning of the aneurysm clip.
                         Methods. Intraoperative angiography was used selectively in this series, based on the surgeon’s concern about
                      the potential for residual aneurysm, distal branch occlusion, or parent vessel stenosis. Specific variables were ana-
                      lyzed to determine their impact on the incidence of clip repositioning and the accuracy of IA was evaluated by direct
                      comparison with postoperative angiography (PA) in 90% of the cases in which IA was used.
                         Conclusions. The selective use of IA led to successful treatment as shown by PA, with a low incidence of unex-
                      pected residual aneurysm (3.2%), distal branch occlusion (1.9%), and parent vessel stenosis (0%). Intraoperative an-
                      giography led to immediate repositioning of the aneurysm clip in 27% of the cases. Anterior cerebral artery aneurysms
                      required clip repositioning less often and superior hypophyseal artery aneurysms required repositioning more often
                      than aneurysms in other locations. Large and giant aneurysms required clip repositioning more often than small aneu-
                      rysms; however, they were also more likely to display false success on IA as determined by PA. Aneurysms arising
                      along the internal carotid artery were more likely to display successful clipping on IA, as determined by PA, than were
                      aneurysms in other locations.
                         The results of this series support the selective use of IA in the treatment of complex aneurysms, particularly large
                      and giant aneurysms as well as superior hypophyseal artery aneurysms. As measured by PA, IA will improve the
                      outcome of these patients.

                      KEY WORDS • intraoperative angiography • cerebral aneurysm • residual aneurysm •
                      distal branch occlusion • digital subtraction angiography • postoperative angiography

       HE goal of aneurysm surgery is to clip the aneurysm              giography was performed to assess the accuracy and reli-
T      in such a manner that there is no residual filling of
       the aneurysm, distal branch occlusion, or stenosis
of the parent vessel. By examining postoperative angiog-
                                                                        ability of the IA findings.
                                                                           In previous reports the potentials for regrowth and hem-
                                                                        orrhage from aneurysm remnants have been documented
raphy (PA), previous reports have found residual aneu-                  as have been the high rates of morbidity and mortality
rysm in as many as 18% of cases 20 and distal branch occlu-             associated with distal branch occlusion.2,8,13,15 If IA is safe
sion in 4 to 24% of cases.2,10,15,21 Although intraoperative            and accurate and its selective use can reduce the incidence
angiography (IA) has been available since the 1960s, few                of postoperative residual aneurysm, distal branch occlu-
neurosurgical centers use this technique routinely.14 Cur-              sion, or parent vessel stenosis, it will play an important
rent uses of IA in aneurysm surgery include diagnostic                  role in reducing the rates of morbidity and mortality asso-
evaluation in emergency cases, in which there is no time                ciated with cerebral aneurysm surgery.
to perform standard preoperative angiography, and intra-
operative assessment of the aneurysm, distal branches,
and parent vessel.1,5,11,12,17 It is also used in conjunction                         Clinical Material and Methods
with interventional techniques such as temporary balloon                Patient Population
occlusion for proximal control or suction decompres-
sion of a large or giant aneurysm.3,12,18,19                              In this prospective study, 151 consecutive patients with
   The goal of this study was to determine whether the                  173 aneurysms underwent surgical treatment between De-
selective use of IA has a favorable impact on the success               cember 1994 and February 1996 by one of three of the
of aneurysm surgery as measured radiographically. We                    authors (T.D.P., T.G.H., or T.J.L.). The patients ranged in
also examined which factors indicate that IA will be ben-               age from 32 to 82 years (mean age 52 years). One hundred
eficial in achieving a successful result. Postoperative an-             twenty-nine aneurysms (75%) occurred in women and 44

J. Neurosurg. / Volume 88 / March, 1998                                                                                                 441
                                                                                                                    T. D. Payner, et al.

                            TABLE 1                                                                   TABLE 2
       Location of 173 consecutively treated aneurysms and                   Characteristics of 173 consecutively treated aneurysms and
                     use of IA in these cases                                                         use of IA*
                                     No. of Aneurysms (%)       Per-                                                   No. of
                                                               centage                             No. of        Aneurysms Evalu-    Percentage
 Location (artery of origin)      Total      Evaluated by IA   of Total   Characteristic       Aneurysms (%)      ated by IA (%)     W/ Specific
                                                                          of Aneurysm           (total = 173)       (total = 70)      Feature
anterior inferior cerebellar      1 (0.6)        1 (1.4)       100
cavernous carotid                 2 (1.2)        2 (2.9)       100        integrity
posterior cerebral                1 (0.6)        1 (1.4)       100          ruptured              121 (70)            42 (60)             35
superior cerebellar               3 (1.7)        3 (4.3)       100          unruptured             52 (30)            28 (40)             54
vertebral                         3 (1.7)        3 (4.3)       100        size
superior hypophyseal              9 (5.2)        8 (11.4)       88.9        small                 115 (66)            31 (44)             27
basilar apex                     10 (5.8)        8 (11.4)       80          large                  45 (26)            27 (39)             60
ophthalmic                       11 (6.4)        6 (8.6)        54.5        giant                  13 (8)             12 (17)             92
anterior choroidal                6 (3.5)        3 (4.3)        50        location
middle cerebral temporal         14 (8.1)        7 (10)         50          ICA                    71 (41)            29 (41)             41
pericallosal                      5 (2.9)        2 (2.9)        40          MCA                    28 (16)            11 (16)             39
posterior inferior cerebellar     8 (4.6)        3 (4.3)        37.5        ACA                    48 (28)            11 (16)             23
middle cerebral bifurcation      14 (8.1)        4 (5.7)        28.6        VBA                    26 (15)            19 (27)             73
carotid terminus                 11 (6.4)        3 (4.3)        27.3
                                                                           * ACA = anterior cerebral artery; ICA = internal carotid artery; MCA =
posterior communicating          34 (19.7)       8 (11.4)       23.5
                                                                          middle cerebral artery; VBA = vertebrobasilar artery.
anterior communicating           41 (23.7)       8 (11.4)       19.5
total                           173 (100)       70 (100)        40.5

                                                                          IA was made at the surgeon’s discretion for one or more
(25%) occurred in men; 121 aneurysms (70%) were rup-                      of six indications. In 60 cases (86%) IA was performed to
tured and 52 (30%) were unruptured. Locations of these                    ensure complete clipping of the aneurysm; in 37 cases
lesions included 147 aneurysms (85%) in the anterior                      (53%) to assess patency of the distal branches; in 29 cases
circulation and 26 aneurysms (15%) in the posterior cir-                  (41%) to ensure uncompromised flow through the parent
culation (Table 1).                                                       vessel; in five cases (7%) to achieve temporary balloon
                                                                          occlusion for proximal control; in 10 cases (14%) for suc-
                                                                          tion decompression of large or giant aneurysms; and in
Technique and Indications for Using IA                                    five emergency cases (7%) because the patient’s condition
   Intraoperative angiography was performed to evaluate                   did not allow enough time to perform preoperative an-
70 aneurysms (40%). Informed consent to perform IA was                    giography. All 70 patients underwent diagnostic IA after
obtained from all patients, although it was not used in all               clipping even when intraoperative balloon techniques or
cases. The groin region was prepared for possible use of                  emergency evaluations had also been performed. The total
IA in all patients. A femoral catheter introducer was                     charge to the patient for diagnostic IA was $2200, which
placed at the start of the procedure or access was obtained               included supplies and technical and professional fees. A
at the time IA was initiated, depending on the position of                cost–benefit analysis is being prepared for future publi-
the patient and the surgeon’s preference. Placement of the                cation.
femoral introducer was made at the start of the operation                    Postoperative angiography was performed routinely to
in 41 cases (59%). This included all cases in which the                   assess the accuracy of the IA and to detect unexpected
patient was positioned laterally for posterior circulation                findings in cases in which IA was not performed. Post-
aneurysms and all cases in which intraoperative interven-                 operative angiography was not performed if the patient
tional techniques such as suction decompression were an-                  refused or died in the early postoperative period or if there
ticipated. In other cases it was up to the individual surgeon             were significant relative contraindications.
to decide when to place the introducer. Among the 29
cases in which the introducer was not placed at the start of              Statistical Analysis
the procedure, there were no aborted attempts to perform                     A standard data collection sheet was used to determine
IA because of failure to gain femoral access. In two of                   the characteristics of each aneurysm and the impact of IA
these cases, localization of the femoral artery was assisted              on the final clip placement. Intraoperative and postopera-
by Doppler sonography, but a percutaneous approach was                    tive angiographic findings were reviewed by both neuro-
successful in all cases. A radiolucent headholder (May-                   surgeons and neuroradiologists to detect any residual
field Radiolucent Headholder; Ohio Medical Instruments,                   aneurysms, distal branch occlusions, and parent vessel
Cincinnati, OH, or Malcom-Rand Carbon-Composite                           stenoses. Data were accrued concurrently and entered into
Headholder; Elekta, Atlanta, GA) and a radiolucent oper-                  a computer database for tabulation and analysis.
ating table (Skytron, Grand Rapids, MI) were used to                         A stepwise logistic regression analysis was performed
enhance the resolution of the IA. Intraoperative angiogra-                to determine any factor that was significantly related to re-
phy was performed by means of a portable digital subtrac-                 positioning of the aneurysm clip after IA and to evaluate
tion angiography unit (OEC Diasonics, Salt Lake City,                     discrepancies between IA and PA findings. Factors in-
UT). All IAs were performed by one of three neurointer-                   cluded patient age and gender and aneurysm type, status,
ventional radiologists (J.A.S., R.L.G., or A.J.D.) who                    size, and location. Significance (p       0.05) was deter-
were available 24 hours per day. The decision to perform                  mined by using Fisher’s exact test.

442                                                                                            J. Neurosurg. / Volume 88 / March, 1998
Intraoperative angiography in aneurysm surgery

                                                                their impact on the need for repositioning of the aneu-
                                                                rysm clip, patient age and gender and aneurysm type were
                                                                not statistically significant. Repositioning of the aneurysm
                                                                clip was required in 10 of 42 ruptured aneurysm and in
                                                                nine of 28 unruptured aneurysms (p = 0.58). Clip re-
                                                                positioning was required in six small (19%), eight large
                                                                (30%), and five giant (42%) aneurysms. Although giant
                                                                aneurysms required clip repositioning at a higher rate than
                                                                smaller aneurysms, this trend was not statistically signifi-
                                                                cant (p = 0.31). The only variable that was significant in
                                                                predicting the necessity for aneurysm clip repositioning
                                                                was location. In fact, aneurysms arising from the anterior
                                                                cerebral artery were statistically significant (p = 0.03) for
                                                                not requiring clip repositioning when compared with other
                                                                aneurysm locations (Fig. 3). Among the locations in
                                                                which there were at least six aneurysms to assess, aneu-
                                                                rysms arising at the superior hypophyseal artery required
                                                                repositioning at a significantly (p = 0.03) higher rate than
   FIG. 1. Bar graph displaying the number of IA studies per-   other locations (Fig. 4).
formed and the number of views obtained in 70 aneurysms.
                                                                Postoperative Angiography
                                                                   Of the 173 aneurysms in this series, 157 (91%) were
                           Results                              evaluated by PA. The remaining patients either did not
Use of Intraoperative Angiography                               survive or declined to undergo PA. Of the 70 aneurysms in
   In this series, IA was performed in 70 (40%) of the 173      patients who underwent IA, 63 (90%) were subsequently
aneurysms surgically treated. The use of IA at the time of      evaluated by PA. Comparison of IA with PA revealed
aneurysm clipping was solely at the discretion of the sur-      identical findings in 53 (84%) of the cases. Among the 10
geon. The most common indication for IA was to ensure           cases (16%) in which there were dissimilarities, eight
complete clipping of the aneurysm (86% of cases). In no         (13%) had unfavorable postoperative findings and two
case in which IA was not performed did PA detect an un-         (3%) had favorable postoperative findings. Unexpected
expected finding. The surgeon’s judgment was highly sen-        unfavorable findings included residual aneurysm in five
sitive (100%) in determining when IA was unnecessary.           cases (7.9%) and distal branch occlusion in three cases
   Characteristics of the total patient population and the      (4.8%) (Fig. 5). No parent vessel stenosis was missed on
subgroup assessed by IA and the percentage of the total         the IA. The two unexpected favorable cases involved ves-
using IA within each category are included in Table 2.          sels that appeared occluded on IA; the clips were not re-
Ruptured aneurysms accounted for 70% of the total num-          positioned because sufficient collateral flow was present
ber of aneurysms and 60% of those assessed by IA. How-          and, subsequently, these vessels were found to be patent
ever, of all ruptured aneurysms, only 35% were selected         on PA (Fig. 6). No unexpected findings were observed on
for IA. With regard to size, giant aneurysms accounted for      PA among the 87 aneurysms that were evaluated only by
only 8% of all aneurysms and 17% of aneurysms assessed          PA and not by IA.
by IA; however, of all giant aneurysms 92% were select-            Among the 157 cases evaluated by PA, the overall inci-
ed for IA. With regard to location, vertebrobasilar aneu-       dence of unexpected residual aneurysm was 3.2% and that
rysms accounted for 15% of all aneurysms and 27% of             of unexpected distal branch occlusion was 1.9%. There
those assessed by IA; of all vertebrobasilar aneurysms          were no cases of unexpected parent vessel stenosis detect-
73% were selected for IA.                                       ed on PA.
   Most patients underwent only one IA study and only
one view (such as anteroposterior or lateral) was obtained.     Complications Related to IA
This view was selected on the basis of which view was             Of the 70 aneurysms evaluated by diagnostic IA, one
determined best on the preoperative angiograms (Fig. 1).        complication (1.4%) occurred. A groin hematoma devel-
Repositioning of the Aneurysm Clip After IA                     oped on the 1st postoperative day in a patient being treat-
                                                                ed with induced hypertension. There were no long-term
   The aneurysm clip was repositioned or an additional          sequelae related to this hematoma.
clip was added after IA in 19 cases (27%). Only those
cases in which the finding on IA was unexpected were
counted in this total. Among these cases, indications for                               Discussion
modifying clip configuration included one or more of the        Selective Use of IA
following: residual aneurysm (eight cases), distal branch
occlusion (eight cases), and parent vessel stenosis (five          Previous studies include retrospective analyses of pa-
cases). Examples of cases in which the patient required         tients harboring aneurysms of whom a subset underwent
aneurysm clip repositioning for each of these indications       IA or a consecutive series in which IA was used routine-
are shown in Fig. 2. Among the variables that were eval-        ly.1,4,6,7,16 In the series conducted by Barrow, et al.,4 and
uated by means of stepwise logistic regression analysis for     Derdeyn, et al.,7 the criteria for performing IA were not

J. Neurosurg. / Volume 88 / March, 1998                                                                                 443
                                                                                                                   T. D. Payner, et al.

            FIG. 2. Angiograms obtained in cases requiring clip repositioning or additional clip placement. Upper: Preoperative
         angiogram (left) obtained in a 47-year-old woman who had a large ruptured posterior inferior cerebellar artery (PICA)
         aneurysm. The distal vertebral artery was difficult to visualize after initial clip placement. The intraoperative angiogram
         (center) shows residual aneurysm beyond the tips of the clip. After addition of a second clip, another angiogram (right)
         shows complete obliteration of the aneurysm; additional clip repositioning was necessary because the PICA is occluded.
         Center: Preoperative angiogram (left) obtained in a 52-year-old woman with a ruptured superior cerebellar artery (SCA)
         aneurysm. After the initial aneurysm clipping, an intraoperative angiogram (center) shows occlusion of the right SCA.
         After clip repositioning, a repeated intraoperative angiogram (right) confirms the patency of the SCA with obliteration
         of the aneurysm. Lower: Preoperative angiogram (left) obtained in a 58-year-old man with a large superior hypophy-
         seal artery aneurysm. An intraoperative angiogram (center) obtained after initial clip placement shows stenosis of the
         internal carotid artery (ICA). After clip repositioning, the ICA is widely patent, as confirmed on the postoperative
         angiogram (right).

provided. Martin and colleagues16 used IA in cases that                     An initial premise of our study was that IA is unneces-
involved large or giant aneurysms, multiple aneurysms,                   sary for every aneurysm operation. Part of the design of
and single aneurysms in a variety of locations. However,                 this study was to determine what circumstances will lead
it is uncertain if that series was exclusive or all-inclusive            the surgeon to use IA and whether PA will confirm that the
for those types of aneurysms. Alexander, et al.,1 used IA                selectivity is reliable. Selection was not based solely on
uniformly without any selectivity in their recently report-              the size or location of the aneurysm; it was also based on
ed series.                                                               the surgeon’s concern immediately after clip placement

444                                                                                           J. Neurosurg. / Volume 88 / March, 1998
Intraoperative angiography in aneurysm surgery

   FIG. 3. Bar graph in which the incidence of repositioning of the
aneurysm clip is plotted against the primary vessel of origin of the      FIG. 4. Bar graph in which repositioning of the aneurysm clip
aneurysm. Aneurysms arising from the ACA were found to require         after IA is plotted against the specific vessel of origin of the
clip repositioning at a statistically significantly lower rate than    aneurysm. Aneurysms arising from the superior hypophyseal
other locations (p = 0.03). ACA = anterior cerebral artery; ICA =      artery required repositioning at a statistically significantly higher
internal carotid artery; MCA = middle cerebral artery; n = number      rate than other locations (p = 0.03). AC = anterior communicating
of aneurysms; VB = vertebrobasilar artery.                             artery; B = basilar artery apex; M1 = anterior temporal branch of
                                                                       middle cerebral artery; n = number of aneurysms; OPH = oph-
                                                                       thalmic artery; PC = posterior communicating artery; SH = superi-
                                                                       or hypophyseal artery.
and on direct microscopic observation for the possibility
of residual aneurysm, distal branch occlusion, or parent
vessel stenosis. We found the surgeon’s judgment to be                 common location for aneurysms that required clip reposi-
very sensitive (100%) in predicting when IA was unnec-                 tioning, although it was not statistically significant. Our
essary: there were no unexpected findings on PA among                  observations are in agreement with a combined series re-
those cases in which no IA was performed. Some sur-                    view of 499 aneurysms evaluated by IA in which a high-
geons may rely on puncture and aspiration of an aneurysm               er incidence of unexpected findings in giant, supraclinoid,
after clipping; however, this does not ensure that there will          and basilar artery aneurysms was found.1
be no residual aneurysm, distal branch occlusion, or par-                 Another explanation for our high rate of repositioning
ent vessel stenosis.                                                   of the aneurysm clip could be that surgeons may rely on
Clip Repositioning After IA                                            IA rather than diligently dissecting and visualizing the
                                                                       neck, parent vessel, and distal branches near an aneurysm.
   The incidence of repositioning or adding an additional              If this were the case, a higher incidence of clip reposition-
aneurysm clip after IA is higher in our series than in other           ing would be expected. However, IA may also prevent
reported series (Table 3). As explained earlier, this result           unnecessary dissection and clip adjustment in cases in
is expected because IA was used selectively in cases in                which the aneurysm has already been properly clipped.
which the surgeon had concern about the final clip con-                Such dissection can result in injury to small perforating
figuration. In few series have factors predictive of the               vessels, intraoperative rupture of the aneurysm, parent
need for clip repositioning been prospectively analyzed.               vessel stenosis, or distal branch occlusion. In this series
Although we agree with Alexander, et al.,1 that the pres-              each aneurysm was dissected and clipped as though IA
ence or absence of subarachnoid hemorrhage does not                    was not available. For aneurysms in the superior hypophy-
predict unexpected findings on IA, we disagree on other                seal artery and basilar artery regions, circumferential visu-
variables. We found only a trend for giant aneurysms to                alization around the neck can be difficult, even with max-
require clip repositioning at a higher rate than smaller               imum dissection, because of the narrow operating window
aneurysms. Perhaps, as our selective use of IA for small               or restrictions at the skull base including the cavernous
aneurysms decreases because of the low incidence of un-                sinus. These restrictions do not exist for other aneurysms
expected findings and as we continue the frequent use of               such as those along the anterior or middle cerebral artery,
IA in cases of giant aneurysms, we can anticipate that the             which have a lower incidence of residual aneurysm, distal
presence of giant aneurysms will be statistically predictive           branch occlusion, and parent vessel stenosis on IA. The
of unexpected IA findings. We did not have the same dif-               results of our series support this because aneurysms of the
ficulty with posterior communicating artery aneurysms as               anterior cerebral artery never required clip repositioning
did Alexander and coworkers; however, superior hypo-                   after IA.
physeal artery aneurysms required the most clip reposi-                   Because superior hypophyseal artery aneurysms re-
tioning for both residual aneurysm and stenosis of the                 quired clip repositioning at the highest rate, they were
carotid artery. The basilar artery was the second most                 assessed independently. This group had a similar variety

J. Neurosurg. / Volume 88 / March, 1998                                                                                                445
                                                                                                                  T. D. Payner, et al.

           FIG. 5. Angiograms showing unfavorable dissimilarities between IA and PA. Upper: Preoperative angiogram (left)
        obtained in a 51-year-old woman presenting with a hemorrhage from a large middle cerebral artery aneurysm. The intra-
        operative angiogram (center) does not show any residual aneurysm; however, the postoperative angiogram (right) con-
        firms a small aneurysm remnant. Lower: Preoperative angiogram (left) obtained in a 45-year-old woman presenting
        with hemorrhage from a dissecting posterior cerebral artery aneurysm. The vessel was reconstructed with aneurysm clips
        to eliminate the aneurysm. The intraoperative angiogram (center) confirms patency of the distal posterior cerebral artery
        aneurysm; the postoperative angiogram (right) shows this vessel is occluded.

of sizes as other locations. The amount of dissection nec-              that may increase the risk of carotid artery compromise or
essary to expose and clip the aneurysms was similar to                  incomplete clipping of the aneurysm, although we did not
other paraclinoid aneurysms. However, superior hypophy-                 assess fenestrated clips as an independent variable in this
seal artery aneurysms frequently require fenestrated clips              series. Other authors did not assess superior hypophyseal

           FIG. 6. Angiograms showing an unexpected favorable dissimilarity between intra- and postoperative angiograms. A:
        Preoperative angiogram obtained in a 53-year-old man who presented with headache and severe gait disturbance caused
        by this giant basilar artery aneurysm. B: Intraoperative angiogram obtained after clip placement showing occlusion of
        the aneurysm with occlusion of the contralateral posterior cerebral artery. C: As seen intraoperatively, this artery filled
        through the posterior communicating artery. D: Postoperative angiogram revealing that the contralateral posterior cere-
        bral artery was actually patent via the basilar artery without repositioning of the clip.

446                                                                                          J. Neurosurg. / Volume 88 / March, 1998
Intraoperative angiography in aneurysm surgery

                           TABLE 3                                                                       TABLE 4
Incidence of aneurysm clip repositioning after IA in the treatment                    Incidence of residual aneurysm detected on PA
                    of cerebral aneurysms                                                        but not recognized on IA
                                       No. of Aneurysms Percentage W/                                         No. of Aneurysms    Residual Aneurysms
          Authors & Year                Evaluated by IA Clip Repositioned         Authors & Year             Evaluated by IA & PA Undetected by IA (%)

Bauer, 1984                                   33               21           Martin, et al., 1990                     22                    12
Martin, et al., 1990                          57                9           Barrow, et al., 1992                     17                     6
Barrow, et al., 1992                          64               11           Derdeyn, et al., 1995                    25                    12
Derdeyn, et al., 1995                         66                9           Payner, et al. (present study)           63                     8
Alexander, et al., 1996                      107               11
Origitano, et al. (unpublished data)          52               19
Payner, et al. (present study)                70               27
                                                                            the internal carotid artery may allow for more reliable
                                                                            findings on IA because they have fewer branches than
                                                                            aneurysms of the middle cerebral bifurcation, anterior
artery aneurysms independent of other paraclinoid aneu-                     communicating artery, or basilar artery. The significance
rysms in a series in which IA was used selectively. Our                     of the increased accuracy of IA for evaluating internal
overall high rate of clip repositioning supports our con-                   carotid artery aneurysms is borderline. We are currently
tention that IA can be used selectively in cases in which it                assessing the use of intraoperative microvascular Doppler
is more likely to have an impact. As our selectivity in the                 sonography in conjunction with IA to increase accuracy.
use of IA increases in the future, our incidence of clip                    Its use may also reduce our utilization of IA, particularly
repositioning may also increase.                                            when trying to evaluate distal branch patency.
Postoperative Angiography                                                      In this series, two cases displayed vessels occluded on
                                                                            IA that were subsequently found to be patent on PA. This
   In previous reports, PA has not been routinely per-                      phenomenon has not been previously reported in other
formed after successful IA; however, in each of our pa-                     series of patients who underwent IA. The clips were not
tients PA was attempted whether IA had been performed                       repositioned after IA because of sufficient collateral flow
or not. Ultimately, PA was performed in 157 aneurysms                       through the posterior communicating artery. Occlusion of
(91%). Intraoperative angiography did not reveal five                       these vessels on IA was attributed to spasm secondary to
(7.9%) of the residual aneurysms and three (4.8%) of the                    surgical manipulation and the lesser force of the hand-
distal branch occlusions. Our incidence of residual aneu-                   injected contrast material that was used with IA, which
rysms that were undetected by IA is similar to those of                     made the vessels appear occluded during IA but not dur-
previously reported series; however, PA was not per-                        ing PA. The PA confirmed antegrade flow in these vessels
formed routinely in those series and thus their incidences                  in both cases. Intraoperative angiography did not lead to
may indeed be higher (Table 4). There is no previous                        repositioning of the clip in these cases because it con-
report of distal branch occlusion undetected by IA.                         firmed that collateral circulation was sufficient to prevent
   Specificity and sensitivity were not calculated for IA                   unnecessary and potentially harmful clip manipulation.
because PA may not reflect the exact condition of the
aneurysms, distal branches, and parent vessel at the time                      With the selective use of IA, the overall incidence of
of the IA. If eight clips were repositioned for residual                    residual aneurysm and distal branch occlusion detected on
aneurysms after IA and five additional aneurysms were                       PA was lower than that of other reported series (Table 5).
detected by PA and presumed undetected by IA, then it                       Distal branch occlusion after aneurysm surgery has high
would appear that the sensitivity of IA was 61% (eight of                   rates of morbidity and mortality.2,15 In 1981, Weir21 report-
13). However, some of these five aneurysms found on                         ed two cases in which immediate PA was performed be-
PA may not have been present during the IA, and may                         cause of neurological deficit and revealed residual aneu-
have formed as a result of aneurysm clip slippage in the                    rysm and distal branch occlusion, resulting in emergency
early postoperative period. The same may apply to distal                    return to the operating room. Intraoperative angiography
branches that appear patent on IA and then thrombose or                     in such a case would likely have eliminated this delay and
become occluded due to spasm and appear occluded on                         reoperation, preventing potential morbidity in the patient.
the PA. Calculating the sensitivity of IA in these scenarios                Our results with selective use of IA led to an incidence
is not reliable. We do assume that all eight residual aneu-                 of distal branch occlusion that was less than half that of
rysms detected on IA would not have resolved sponta-                        any previously reported series assessed by PA results
neously and would most certainly have been present on                       (Table 5).
PA if the clips had not been repositioned. Therefore, the
clinically relevant interpretation of these data is that IA re-             Complications of IA
duced the incidence of residual aneurysm on PA by 61%.
   In our series, IA was more accurate in the evaluation of                    One groin hematoma related to IA occurred in a patient
small aneurysms and in those arising from the internal                      being treated with induced hypertension following
carotid artery branches. Identification of small aneurysms                  surgery. There were no strokes related to the use of diag-
would be expected to be more accurate on IA because they                    nostic IA. Our incidence of complications is 1.4%. Others
are more easily visualized circumferentially during sur-                    have confirmed the safety of IA in evaluating aneurysms
gery and, therefore, are less likely to have unexpected re-                 as well as arteriovenous malformations and carotid arter-
sidual aneurysm or distal branch occlusion. Aneurysms of                    ies after endarterectomy.4,7,16

J. Neurosurg. / Volume 88 / March, 1998                                                                                                          447
                                                                                                                      T. D. Payner, et al.

                            TABLE 5                                          4. Barrow DL, Boyer KL, Joseph GJ: Intraoperative angiography
  Incidence of residual aneurysms and distal branch occlusions                  in the management of neurovascular disorders. Neurosurgery
               detected on PA with or without IA*                               30:153–159, 1992
                                                                             5. Batjer HH, Frankfurt AI, Purdy PD, et al: Use of etomidate,
                                   No. of      Residual    Distal Branch        temporary arterial occlusion, and intraoperative angiography in
    Authors & Year                Patients   Aneurysms (%) Occlusions (%)       surgical treatment of large and giant cerebral aneurysms. J
                                                                                Neurosurg 68:234–240, 1988
Allcock & Drake, 1963               70            8.6            8.6         6. Bauer BL: Intraoperative angiography in cerebral aneurysm and
Steven, 1966                       260           18             NR              AV-malformation. Neurosurg Rev 7:209–217, 1984
                                   191           NR             24           7. Derdeyn CP, Moran CJ, Cross DT, et al: Intraoperative digital
Feuerberg, et al., 1987            715            2.2           NR
                                                                                subtraction angiography: a review of 112 consecutive examina-
Friedman, et al., 1987              50           NR              4
Barrow, et al., 1992                17            6             NR
                                                                                tions. AJNR 16:307–318, 1995
MacDonald, et al., 1993             78            8             12           8. Drake CG, Vanderlinden RG: The late consequences of incom-
Payner, et al. (present study)     151            3.2            1.9            plete surgical treatment of cerebral aneurysms. J Neurosurg
                                                                                27:226–238, 1967
 * NR = not reported.                                                        9. Feuerberg I, Lindquist C, Lindqvist M, et al: Natural history of
                                                                                postoperative aneurysm rests. J Neurosurg 66:30–34, 1987
                                                                            10. Friedman WA, Kaplan BL, Day AL, et al: Evoked potential
                                                                                monitoring during aneurysm operation: observations after fifty
                       Conclusions                                              cases. Neurosurgery 20:678–687, 1987
   Intraoperative angiography led to repositioning of the                   11. Hieshima GB, Reicher MA, Higashida RT, et al: Intraoperative
aneurysm clip in 27% of cases. Its selective use led to                         digital subtraction neuroangiography: a diagnostic and thera-
radiographic success on PA with a low incidence of unex-                        peutic tool. AJNR 8:759–767, 1987
                                                                            12. Lazar ML, Watts CC, Kilgore B, et al: Cerebral angiography
pected residual aneurysm (3.2%), distal branch occlusion                        during operation for intracranial aneurysms and arteriovenous
(1.9%), and parent vessel stenosis (0%). Intraoperative                         malformations. Technical note. J Neurosurg 34:706–708,
angiography proved to be a safe procedure with a low                            1971
complication rate (1.4%). Anterior cerebral artery aneu-                    13. Lin T, Fox AJ, Drake CG: Regrowth of aneurysm sacs from
rysms required clip repositioning less often (p = 0.03) and                     residual neck following aneurysm clipping. J Neurosurg 70:
superior hypophyseal artery aneurysms more often (p =                           556–560, 1989
0.03) than those in other locations. Large and giant aneu-                  14. Loop JW, Foltz EL: Applications of angiography during intra-
rysms were more likely to have dissimilarities between                          cranial operation. Acta Radiol (Diagn) 5:363–367, 1966
intra- and postoperative angiograms than small aneurysms                    15. MacDonald RL, Wallace MC, Kestle JRW: Role of angiogra-
(p = 0.03). There was a trend for better agreement between                      phy following aneurysm surgery. J Neurosurg 79:826–832,
intra- and postoperative angiograms in aneurysms of the                     16. Martin NA, Bentson J, Viñuela F, et al: Intraoperative digital
internal carotid artery than for aneurysms in other loca-                       subtraction angiography and the surgical treatment of intracra-
tions (p = 0.07). We believe that selective use of IA is an                     nial aneurysms and vascular malformations. J Neurosurg 73:
essential component in the treatment of cerebral aneu-                          526–533, 1990
rysms because it will improve the successful outcome of                     17. Martin NA, Doberstein C, Bentson J, et al: Intraoperative
patients as measured on PA.                                                     angiography in cerebrovascular surgery. Clin Neurosurg 37:
                                                                                312–331, 1991
                           Acknowledgments                                  18. Scott JA, Horner TG, Leipzig TJ: Retrograde suction decom-
                                                                                pression of an ophthalmic artery aneurysm using balloon occlu-
   The authors thank Jessie Koers, R.N., for her assistance in col-             sion. Technical note. J Neurosurg 75:146–147, 1991
lection of data for this study and David Nelson, M.S., for his exper-       19. Shucart WA, Kwan ES, Heilman CB: Temporary balloon
tise in biostatistical analysis.                                                occlusion of a proximal vessel as an aid to clipping aneurysms
                                                                                of the basilar and paraclinoid internal carotid arteries: technical
                                 References                                     note. Neurosurgery 27:116–119, 1990
                                                                            20. Steven JL: Postoperative angiography in treatment of intracra-
 1. Alexander TD, MacDonald RL, Weir B, et al: Intraoperative an-               nial aneurysms. Acta Radiol (Diagn) 5:536–547, 1966
    giography in cerebral aneurysm surgery: a prospective study of          21. Weir B: Value of immediate postoperative angiography follow-
    100 craniotomies. Neurosurgery 39:10–18, 1996                               ing aneurysm surgery. Report of two cases. J Neurosurg 54:
 2. Allcock JM, Drake CG: Postoperative angiography in cases                    396–398, 1981
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    1963                                                                      Manuscript received April 28, 1997.
 3. Bailes JE, Deeb ZL, Wilson JA, et al: Intraoperative angiogra-            Accepted in final form October 14, 1997.
    phy and temporary balloon occlusion of the basilar artery as an           Address reprint requests to: Troy D. Payner, M.D., Indianapolis
    adjunct to surgical clipping: technical note. Neurosurgery 30:          Neurosurgical Group, 1801 North Senate Boulevard, Suite 535,
    949–953, 1992                                                           Indianapolis, Indiana 46202.

448                                                                                              J. Neurosurg. / Volume 88 / March, 1998

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