While posterior fossa decompression (PFD) is considered the standard treatment for symptomatic Chiari malformation type I (CM-I),1 indications for PFD with duraplasty (PFDD) versus PFD with extradural decompression only (PFDo) are less well defined, particularly in patients with concurrent syringomyelia and scoliosis. Among patients who undergo decompressive surgery for CM-I, the prevalence of syringomyelia is nearly 75%.39 Furthermore, up to 60%–70% of patients with CM-I and syrinx also have scoliosis,2–6 and several reports show an association of syrinx characteristics with scoliosis in CM-I patients.7,8 However, the association of CM-I with scoliosis in the absence of a syrinx is not known at this time.4,9,10
In patients with CM-I, those with syringomyelia and/or scoliosis are more likely to undergo surgery;1,11 however, the incidence of improvement or stabilization of scoliosis after PFD is variable, with 18%–70% of patients undergoing further intervention such as spinal fusion.3,8,12–17 A number of factors have been associated with fusion after PFD, including older age at decompression, initial curve magnitude, and syrinx reduction postsurgery.4,13
Although age at PFD and scoliosis severity have been reported as predictors of curve progression post-PFD,4,15,16,18–21 the type of PFD surgery (PFDo vs PFDD) has not been examined in a large cohort with respect to scoliosis curve progression or subsequent occurrence of fusion. We report scoliosis outcomes after PFDD versus PFDo in what is to our knowledge the largest cohort of patients reported in the literature with CM-I, syrinx, and scoliosis.
Methods
Cohort Description
After institutional review board approval was received from all participating centers, clinical, demographic, and imaging records for the first 1257 patients enrolled in the Park-Reeves Syringomyelia Research Consortium database were reviewed. These data included patients from 36 centers with ages up to 21 years who presented for management of CM-I and syrinx. All patient records were de-identified and patients were assigned a site-subject number. A combination of retrospective and prospective patient data for the study cohort was used. Retrospective subjects must have been treated within the last 15 years and have preoperative MRI scans. Prospective subjects were enrolled from July 2011 to May 2019 and followed for up to 5 years at each site. Of the 1257 patients in the study cohort, 313 were recruited retrospectively and 944 were recruited prospectively. Data from each site were entered into the central database by individual site coordinators/investigators and all entries were monitored and overseen remotely by data monitor personnel at the lead site (Washington University in St. Louis). It should be noted that although we used consecutive patients from the Park-Reeves database, there may have been an inherent bias in that the accrual of patients to the database is left to the individual centers, and thus we cannot be certain of each center’s sampling practices.
Imaging and Clinical Review Criteria
Patients were included if they had a clinical diagnosis of scoliosis reported in the medical record. All patients with available preoperative imaging had tonsil position ≥ 5 mm below the foramen magnum and a syrinx ≥ 3 mm in length. For an imaging diagnosis of scoliosis, formal upright 36-inch radiographs were inconsistently available in the database, and therefore coronal MRI or CT images were used in addition to plain radiographs.8 Of those with a clinical diagnosis of scoliosis, 278 had imaging data available to measure curve magnitude: n = 126 (MRI), n = 3 (CT), and n = 149 (radiograph). Radiographic parameters assessed included Cobb angle, and MRI parameters included tonsil position, syrinx length (in vertebral levels), syrinx width, and holocord syrinx. The change in syrinx dimensions (width and length) was assessed based on pre- and postsurgical MRI. Curve progression was defined as at least a 10° increase in curve magnitude, curve improvement was defined as at least a 10° decrease in curve magnitude, and curve stability was defined as up to a −10° to up to a +10° change in curve magnitude.3,19 For the outcome of fusion, we indicated occurrence of fusion as the outcome variable (and not need for fusion), as there may be practice variations between institutions regarding the threshold for surgical intervention for correction of scoliosis.
Statistics
Univariate and multivariate analyses were performed with logistic regression using the GLM function in R. The correlation between continuous variables was determined by linear regression using the GLM function in R. Univariate and multivariate analyses were performed for all variables in the model (Supplementary Tables). Only univariate analysis was performed for bracing data due to the small number of patients treated with a brace (Supplementary Table 5). Paired two-tailed t-tests were performed to compare curve or syrinx sizes between two time points in the same CM-I patients. When comparing differences between the two surgery groups in curve progression and syrinx size, as well as the clinical and imaging variables listed in Table 1, two-tailed, two-sample, equal variance t-tests were performed. All associations with covariates were performed in the R statistical software package using the linear model function, and for statistical analyses of counts of people between groups, Fisher’s exact test in R was used. Differences with p ≤ 0.05 were deemed statistically significant. Kaplan-Meier curves were created using the survival and ggplot2 packages in R (https://cran.r-project.org/; R Project for Statistical Computing).
Demographic, radiological, and clinical variables with extradural decompression only and duraplasty
| Extradural Decompression | Duraplasty | p Value | |
|---|---|---|---|
| Demographic characteristics | |||
| Clinical scoliosis | 51 | 346 | — |
| Female, % | 71 | 62 | 0.46 |
| CM-I diagnosis, yrs | 10.26 | 10.32 | 0.92 |
| Age at PFD, yrs | 10.64 | 10.66 | 0.98 |
| Fusion | 13.7 | 12.3 | 0.11 |
| No fusion | 9.7 | 10.3 | 0.41 |
| Radiological characteristics | |||
| Tonsil position, mm | 12.2 | 12.5 | 0.69 |
| Preop curve magnitude, ° | 29.9 | 28.8 | 0.68 |
| Follow-up imaging, days | 226 | 252 | 0.99 |
| Clinical characteristics | |||
| Clinical follow-up, yrs | 2.62 | 2.60 | 0.95 |
| Scoliosis follow-up (fusion), yrs | 2.36 | 2.02 | 0.64 |
| Scoliosis follow-up (no fusion), yrs | 1.48 | 0.93 | 0.23 |
| With bracing, % | 22 | 14 | 0.31 |
| Scoliosis outcomes | |||
| Fusion, no. (%) | 23 (12) | 19 (67) | 0.59 |
| Age at fusion, yrs | 14.51 | 13.76 | 0.35 |
| Curve progression, % | 38 | 19 | 0.31 |
| Stable curve, % | 62 | 74 | 0.34 |
| Curve improvement, % | 0 | 7 | 0.59 |
| Curve progression, ° | 9.3 | 3.6 | 0.11 |
Data are presented as number of patients or mean unless otherwise indicated.
Results
Of the 1257 patients reviewed in this cohort, 422 had a clinical diagnosis of scoliosis and 63% of patients with scoliosis were female (Table 1). All 422 patients underwent decompression surgery. In 25 patients (6%), the type of surgery performed was not recorded, and thus they were excluded. In total, 397 patients were included in our analysis, of whom 346 (87%) had a PFDD and 51 (13%) underwent PFDo. The average patient age at the time of surgery was 10.6 ± 3.98 years. The average clinical follow-up was 2.60 ± 2.05 years for those who underwent PFDD and 2.62 ± 2.16 years for those who underwent PFDo (p = 0.95). The average age at CM-I diagnosis was 10.32 (range 3–20) and 10.26 (range 3–17) years in the PFDD and PFDo groups, respectively. These clinical follow-up ranges are consistent with those reported for previous studies on scoliosis progression after PFD.16,22 There were no differences in baseline characteristics between the two groups with respect to age, sex, tonsil position, preoperative curve magnitude, or proportion of patients with holocord syrinx. Patients who underwent a PFDD had significantly wider (8.9 vs 7.6 mm, p = 0.02) and longer (10.7 vs 9.4 vertebral levels, p = 0.04) preoperative syrinxes than those receiving PFDo (Table 2). Sixty-five patients (15%) underwent bracing as a treatment for their scoliosis, including 14% of patients in the PFDD group and 22% of patients in the PFDo group (p = 0.3); 5% of those receiving PFDD required PFD revision surgery (17 of 346), compared to 14% of those receiving PFDo (8 of 51), and this difference was statistically significant (p = 0.02, OR 2.93, 95% CI 1.78–4.08). The average age at CM-I surgery for those needing revision was 11.05 years, and 11 of 25 revision patients were female.
Syrinx characteristics for extradural decompression only and duraplasty
| Extradural Decompression | Duraplasty | p Value | |
|---|---|---|---|
| Syrinx width, mm | |||
| Before PFD | 7.6 | 8.9 | 0.02 |
| After PFD | 2.2 | 1.9 | 0.53 |
| Change | −5.4 | −7.0 | 0.03 |
| Syrinx length, vertebral levels | |||
| Before PFD | 9.4 | 10.7 | 0.04 |
| After PFD | 9.6 | 8.2 | 0.15 |
| Change | −0.6 | −2.3 | 0.08 |
| Holocord syrinx, % | 34 | 50 | 0.10 |
Boldface type indicates statistical significance.
Preoperative Imaging and Subsequent Occurrence of Fusion
Presurgical anterior-posterior or coronal imaging data for 278 patients were available for review. Preoperative curve magnitude was similar between the extradural decompression and duraplasty groups (29.9° and 28.8°, respectively; Table 1). Consistent with prior reports, we found that patients who ultimately underwent surgical correction of scoliosis had larger preoperative curve magnitude (40.2° vs 25.9°, p < 0.001; Table 3) at the time of PFD, although this was only significant in the PFDD group (t-test, p < 0.001) when stratified by surgery type, likely due to small sample size in the PFDo group (Table 1, Fig. 1). However, patients who ultimately underwent a fusion were significantly older at the time of PFD than those who did not undergo fusion (12.14 vs 10.22 years, t-test, p < 0.0001; Supplementary Table 1), and this finding was present in both the PFDo and PFDD groups (Table 1).
Scoliosis progression in degrees stratified by PFD type and spinal fusion
| Curve Magnitude Pre-PFD | Curve Magnitude Post-PFD | Change in Curve | |
|---|---|---|---|
| All patients | |||
| Fusion | 40.2° | 54.0° | +13.8° |
| No fusion | 25.9° | 27.9° | +2.0° |
| Extradural decompression | |||
| Fusion | 46.9° | 57.3° | +10.4° |
| No fusion | 28.3° | 37.1° | +8.8° |
| Duraplasty | |||
| Fusion | 38.3° | 53.0° | +14.7° |
| No fusion | 25.7° | 26.8° | +1.2° |
Comparison of preoperative curve severity (degrees) between patients who underwent PFDo and those who underwent PFDD stratified by whether patients ultimately underwent further surgical treatment for scoliosis (*p < 0.001).
Fusion After PFDD Versus PFDo
Twenty-three percent of patients (n = 12) ultimately underwent surgical correction of scoliosis after PFDo compared to 19% of patients (n = 67) after PFDD (p = 0.59; Table 1, Fig. 2).
Kaplan-Meier curve of time (in years) to fusion after PFD in patients with and patients without duraplasty.
Curve Progression After PFDD Versus PFDo
Curve progression was only analyzed in a subset of patients (13 with PFDo and 99 with PFDD) who had both preoperative and postoperative imaging (radiograph, CT, or MRI in the anterior-posterior, posterior-anterior, or coronal plane), obtained an average of 14.5 months after PFD. On direct comparison, there was no significant difference in the percentages of patients with curve progression (p = 0.31) or magnitude of curve progression (p = 0.11) after PFDo versus PFDD (Table 1). At the time of PFD, patients whose curves subsequently progressed were on average 12.15 ± 2.71 years of age, and patients who subsequently remained stable or improved were on average 10.10 ± 4.02 years of age (p = 0.02). There were no differences based on sex between the patients who remained stable, improved, or progressed. There was no difference in curve progression based on curve location or leftward direction of the thoracic curve.
When considering only those patients who ultimately underwent fusion, those receiving PFDo had, on average, a 10.4° ± 17° curve progression from first imaging to imaging before fusion, and those with PFDD had, on average, a 14.7° ± 20° progression (p = 0.7). However, in patients who ultimately did not undergo a fusion, those with PFDo had an average increase in curve magnitude of 8.8° ± 14° compared to 1.2° ± 9.7° in those with PFDD (p = 0.03; Fig. 3).
Change in curve magnitude postoperatively stratified by type of decompression surgery and later occurrence of fusion (*p < 0.05).
Occurrence of Post-PFD Fusion Is Associated With Both Older Age at PFD and Larger Preoperative Curve
In a logistic regression model, after controlling for tonsil position, syrinx characteristics (length, width, presence of holocord syrinx), sex, age at surgery, and preoperative curve magnitude, there was no association between type of PFD and subsequent occurrence of fusion. However, when controlling for the above variables, there was a significant association of older age at PFD surgery (p = 0.02, OR 1.02 per additional year, 95% CI 1.003–1.030) and larger preoperative curve magnitude (p < 0.001, OR 1.01 per additional degree, 95% CI 1.005–1.011) with subsequent occurrence of fusion (Supplementary Tables 1 and 2). There was a near-significant association between subsequent occurrence of fusion and female sex (p = 0.051, OR 1.10, 95% CI 1.000–1.218).
Older Age at CM-I Surgery and PFDo Are Independently Associated With Curve Progression
In a logistic regression model evaluating independent factors associated with curve progression > 10°, there was no association with sex, tonsil position, syrinx characteristics, or preoperative curve with curve progression > 10°. However, older age at surgery (p = 0.03, OR 1.02 per additional year, 95% CI 1.002–1.047) and PFDo (p = 0.02, OR 1.37, 95% CI 1.054–1.779) were independently associated with curve progression > 10° (Supplementary Tables 3 and 4).
Bracing Reduces Rates of Fusion
While there was no significant difference in the rate of patients undergoing bracing after PFDD versus PFDo (14% vs 22%, p = 0.31; Table 1), bracing was associated with a reduced occurrence of fusion (p = 0.003) but not curve progression (p = 0.182; Supplementary Table 5).
PFDD and PFDo Both Significantly Reduce Syrinx Width
Patients who underwent PFDD had an overall greater reduction in syrinx width than those who underwent PFDo (7.0 mm [−79%] vs 5.4 mm [−71%], p = 0.03), although patients in the PFDD group also had a larger starting syrinx width than those in the PFDo group (8.9 vs 7.6 mm, p = 0.02; Table 2). Nonetheless, syrinx width in both groups was substantially decreased after PFD of either type (down to 1.9 mm with PFDD and 2.2 mm with PFDo, p = 0.53).
Syrinx length measurements before and after PFD were only available for a small portion of patients (35% PFDo, 41% PFDD). However, similar to syrinx widths, the average preoperative syrinx length in patients who subsequently underwent PFDD was significantly longer than the syrinx length in those who subsequently underwent PFDo (10.7 vertebral levels vs 9.4 vertebral levels, respectively; p = 0.04). Syrinx length in the PFDo patients decreased on average 0.6 vertebral levels (−6%) versus 2.3 (−21%) in PFDD patients (p = 0.08).
Both Curve Progression and Post-PFD Fusion Are Associated With Reduction of Syrinx
Although reduction of syrinx width after PFD was not significantly associated with reduced curve progression (p = 0.76), reduction in syrinx width was significantly associated with reduced subsequent occurrence of fusion (p = 0.01, OR 0.99 per 1 mm reduction, 95% CI 0.975–0.997). Likewise, while there was no significant association between change in syrinx length and curve progression after PFD (p = 0.93), there was a near-significant association between change in syrinx length and subsequent occurrence of fusion (p = 0.051).
Discussion
Examination of CM-I Patients With Both Syrinx and Scoliosis
We report the largest cohort of patients with CM-I–syrinx and scoliosis and are the first to compare scoliosis outcomes in this group between those undergoing PFD with or without duraplasty. Many studies of the effect of PFD on pediatric CM-I–syringomyelia and scoliosis do not specifically report or control for whether duraplasty was employed,3,4,12,13,23 and many others exclude PFDo entirely.16,17 Although a smaller group of studies has investigated the difference in outcomes between PFDo and PFDD with primary endpoints of clinical improvement and change in syrinx, only one study reported progression of scoliosis.24–29 The relationship between CM-I and scoliosis in the absence of syringomyelia is uncertain. Prior studies have found that scoliosis in the presence of CM-I without syringomyelia may still appear similar to CM-I with syringomyelia and respond similarly to PFD;30,31 however, the opposite has also been observed.10 It is therefore still important to assess the impact of treatment in patients with CM-I, scoliosis, and concurrent syringomyelia. Our study cohort is the first, to our knowledge, in which responses of patients with all three related conditions were compared for these different PFD modalities.
Duraplasty Reduces Curve Progression Post-PFD but Not Rates of Spinal Fusion
We found that use of duraplasty was associated with reduced curve progression after PFD, as was younger age at PFD. Age at time of PFD has been repeatedly shown to correlate with curve progression after decompression,4,13,16,22 as it does with fusion. However, this is the first study that we are aware of to date that has reported a correlation between duraplasty and reduced curve progression after PFD. The fact that we also observed a significant difference in the proportion of CM-I revision surgeries between the two groups, with PFDo patients requiring significantly more revisions than PFDD patients, may further support PFDD over PFDo for the treatment of CM-I– and syrinx-associated scoliosis.
When controlling for factors such as age, sex, preoperative curve, tonsil position, and type of PFD surgery, we found that syrinx characteristics including width, length, and presence of a holocord syrinx were not associated with the subsequent occurrence of fusion or with curve progression. This finding is consistent with current literature on the topic.13,32 Our results suggest that while syringomyelia is closely tied to the development of scoliosis,8,10 the effect of syringomyelia on scoliosis progression may be alleviated by surgical decompression.
The follow-up range in this study is consistent with previous studies on scoliosis progression after PFD;16,22 however, our results may not be generalizable beyond this time period. There is a generally recognized curve threshold of 50°,6,33 above which patients are considered for surgical scoliosis correction. Our findings suggest that a greater preoperative curve does not lead to progression of scoliosis after PFD, but a more severe curve typically persists after decompression, leading to a greater postoperative curve magnitude, itself an indication for scoliosis surgery. Given the strong association between curve progression and occurrence of fusion, further investigation with a larger sample size may be needed to clarify this difference.
However, we found no association between type of PFD and the occurrence of fusion. This suggests that being younger at the time of PFD and having a smaller baseline curve may predict a lower likelihood of future scoliosis correction, irrespective of whether the PFD included a duraplasty. We do note that we are underpowered to detect associations with the current sample sizes. In the future, we plan to repeat this analysis with a larger sample size.
Bracing Is Associated With Reduced Post-PFD Fusion Rates
While there was no significant difference in the number of patients who underwent bracing after PFDD versus PFDo, bracing was associated with a reduced occurrence of fusion after PFD but not with reduced curve progression (Supplementary Table 5). Bracing has been found to reduce the likelihood that a scoliosis curve will progress to a 50° threshold,34 supporting our finding that it is associated with reduced likelihood for fusion. However, contrary to our findings, bracing has also been shown to reduce rates of scoliosis curve progression overall.35 The difference likely lies in our small sample size: as only 34 patients had data for both curve progression and bracing, the sample size was too small to include bracing in our multivariate analysis, so we were not able to control for this variable and its effects on fusion and curve progression. As a result, bracing may represent a confounding variable in the present analyses.
PFDo and PFDD Both Significantly Reduce Syrinx Width
We found that both PFDo and PFDD significantly reduced syrinx size. However, PFDD led to significantly greater reductions in syrinx width and trended toward greater reductions in syrinx length. Similarly, a 2018 meta-analysis of 3666 adult and pediatric CM-I patients reported greater syrinx reduction with the inclusion of duraplasty.36 However, numerous exclusively pediatric studies,25,28 including the largest meta-analysis on the subject to date,24 have concluded that PFDD was no better at reducing syrinx size in children with CM-I than PFDo. In our cohort, preoperative syrinx length and width were greater among the patients who underwent PFDD surgery (Table 2). It is therefore possible that the greater resolution of syrinx after PFDD that we observed may result from this baseline difference in syrinx size, rather than the different surgical technique used. Alternatively, our cohort with CM-I, syringomyelia, and scoliosis may represent a unique population with distinct characteristics and a different response to decompressive surgery than those with CM-I–syringomyelia alone. Further study in this unique pediatric population is warranted.
Fusion and Curve Progression After Change in Syrinx
We observed a significant association between reduction in syrinx width after PFD and reduced occurrence of spinal fusion, and a near-significant association between reduction in syrinx length and reduced incidence of subsequent fusion. These findings support the current literature, which repeatedly demonstrates a reduction in curve progression and fusion rates in patients who experience greater syrinx resolution after PFD,37,38 and up to a fourfold increased likelihood of curve progression in those who do not experience syrinx resolution.3 The mechanism underlying this stabilization is unclear, but it appears syrinx resolution alone is not the cause, as reduction of syrinx from shunting does not improve scoliosis.37 Rather, reduction in syrinx after PFD may serve as a metric of the success or extent of craniocervical decompression, which then affects scoliosis progression by an alternate mechanism.
In contrast to the literature, we found no association between reduction of syrinx width or syrinx length and curve progression after PFD.38 As previously noted, in contrast to our analysis of fusion, analysis of curve progression is far more limited in power due to the relative paucity of patients with both pre- and postoperative measurements of syrinx size and scoliosis severity. Further investigation with more extensive pre- and postoperative imaging would allow for more detailed analysis of changes resulting from PFD and a better understanding of the relationship between curve progression and fusion.
Study Limitations
This study has some limitations. First, the size discrepancy between the PFDo and PFDD groups is a limitation for detecting other potentially significant differences between the groups. As stated in prior reports from the Park-Reeves Syringomyelia Research Consortium, another significant limitation of this data set is its ability to enable evaluation of curve magnitude at baseline and over time. There are a limited number of patients with true deformity radiographs, and there is no information on positioning during imaging (supine vs weight-bearing). Therefore, we have used coronal MRI and CT in addition to radiographs to assess curve magnitude. Further, due to the modest number of patients with follow-up imaging, curve degree was assessed on all imaging modalities, including radiograph, CT, and MRI, and for 10 patients, comparison between multiple imaging types was used. Given the limitation of imaging to assess scoliosis, we included all patients with a clinical diagnosis of scoliosis and used subsequent occurrence of fusion as a primary outcome variable, although the decision and timing for fusion were surgeon preference and not controlled for inclusion. The analysis of fusion included patients with a preoperative curve magnitude so severe that fusion was inevitable regardless of decompression surgery, thereby limiting the observed effect of decompression on likelihood of fusion. Curve progression was analyzed as a secondary outcome and was therefore more limited by imaging availability and follow-up duration than fusion. Similarly, analysis of bracing and scoliosis outcomes was limited by the small number of patients for whom these data were collected in our sample. Regarding type of PFD, we grouped all types of duraplasty together, and there may, in fact, be differences between types of duraplasty used in PFDD. We did not analyze complications associated with PFD, as this is the focus of another study. We were unable to control for the primary indication for receiving spinal imaging, because this information was not available in the data set, thereby allowing a potential sampling bias. Likewise, we did not analyze the primary indication for surgery for each patient; it is therefore possible that patients with less severe presentations may have been biased toward the less invasive PFDo surgery, despite controlling for radiographic parameters. Future analysis would incorporate surgical outcomes in the context of scoliosis outcomes. A longer follow-up interval will enable the capture of more long-term outcomes after PFD. Finally, this is not a randomized or fully prospective study, and it therefore has inherent limitations related to bias in allocating surgical and nonsurgical interventions, surgical procedure type, and follow-up visits and imaging. Given the relatively smaller sample size of patients receiving an extradural decompression, further investigation is needed to assess scoliosis outcomes in this group.
Conclusions
In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in the occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with extradural decompression alone. However, when controlling for age, sex, preoperative curve, tonsil position, and syrinx characteristics, PFDD was significantly associated with reduced subsequent curve progression compared to PFDo. Further study is needed to evaluate the role of duraplasty in curve stabilization and the occurrence of spinal fusion after PFD in order to guide clinical management.
Acknowledgments
We would like to acknowledge the Reeves family and their friends for their generosity, which is responsible for the Park-Reeves Syringomyelia Research Consortium.
Disclosures
Dr. Adelson reports being a consultant for Medtronic. Dr. Bierbrauer reports receiving clinical or research support for the study described (includes equipment or material) from the Park-Reeves Syringomyelia Research Consortium, which helped sponsor research by paying for support used for the research coordinator position that helped enroll study participants. Dr. Limbrick reports receiving support of non–study-related clinical or research effort from Medtronic and Microbot Medical.
Author Contributions
Conception and design: Strahle, Anderson. Acquisition of data: Sadler, Skidmore, Gewirtz, Haller, Ackerman, Adelson, Ahmed, Albert, Aldana, Alden, Averill, Baird, Bauer, Bierbrauer, Bonfield, Brockmeyer, Chern, Couture, Daniels, Dlouhy, Durham, Ellenbogen, Eskandari, Fuchs, George, Grant, Graupman, Greene, Greenfield, Gross, Guillaume, Hankinson, Heuer, Iantosca, Iskandar, Jackson, Jea, Johnston, Keating, Khan, Krieger, Leonard, Maher, Mangano, Mapstone, McComb, McEvoy, Meehan, Menezes, Muhlbauer, Oakes, Olavarria, O’Neill, Ragheb, Selden, Shah, Shannon, Smith, Smyth, Stone, Tuite, Wait, Wellons, Whitehead, Park, Limbrick. Analysis and interpretation of data: Strahle, Sadler, Skidmore, Anderson, Limbrick. Drafting the article: Sadler, Skidmore. Critically revising the article: Strahle, Sadler, Skidmore, Anderson, Haller, Ackerman, Adelson, Ahmed, Albert, Aldana, Alden, Averill, Baird, Bauer, Bierbrauer, Bonfield, Brockmeyer, Chern, Couture, Daniels, Dlouhy, Durham, Ellenbogen, Eskandari, Fuchs, George, Grant, Graupman, Greene, Greenfield, Gross, Guillaume, Hankinson, Heuer, Iantosca, Iskandar, Jackson, Jea, Johnston, Keating, Khan, Krieger, Leonard, Maher, Mangano, Mapstone, McComb, McEvoy, Meehan, Menezes, Muhlbauer, Oakes, Olavarria, O’Neill, Ragheb, Selden, Shah, Shannon, Smith, Smyth, Stone, Tuite, Wait, Wellons, Whitehead, Park, Limbrick. Reviewed submitted version of manuscript: all authors. Statistical analysis: Sadler, Skidmore. Administrative/technical/material support: Strahle, Bethel-Anderson. Study supervision: Strahle, Limbrick.
Supplemental Information
Online-Only Content
Supplemental material is available with the online version of the article.
Supplementary Tables 1–5. https://thejns.org/doi/suppl/10.3171/2020.12.PEDS20552.
Previous Presentations
Posterior fossa decompression with or without duraplasty for scoliosis associated with Chiari malformation with syringomyelia, by Sadler B, Gewirtz J, Skidmore A, Anderson R, Haller G, Park TS, Limbrick DD, and Strahle J, was presented as an abstract in a plenary session of the 48th AANS/CNS Section on Pediatric Neurological Surgery, Scottsdale, AZ, December 5–8, 2019.
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