Radiological and clinical associations with scoliosis outcomes after posterior fossa decompression in patients with Chiari malformation and syrinx from the Park-Reeves Syringomyelia Research Consortium

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  • 1 Department of Neurological Surgery, Washington University School of Medicine, St. Louis, Missouri;
  • | 2 Department of Epidemiology, University of Iowa, Iowa City, Iowa;
  • | 3 Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee;
  • | 4 Department of Neurosurgery, Neuroscience Institute, Johns Hopkins All Children’s Hospital, St. Petersburg, Florida;
  • | 5 Department of Radiology, Washington University School of Medicine, St. Louis, Missouri;
  • | 6 Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, New York; and
  • | 7 Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri
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OBJECTIVE

In patients with Chiari malformation type I (CM-I) and a syrinx who also have scoliosis, clinical and radiological predictors of curve regression after posterior fossa decompression are not well known. Prior reports indicate that age younger than 10 years and a curve magnitude < 35° are favorable predictors of curve regression following surgery. The aim of this study was to determine baseline radiological factors, including craniocervical junction alignment, that might predict curve stability or improvement after posterior fossa decompression.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and a syrinx (≥ 3 mm in width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°) in patients who underwent posterior fossa decompression and who also had follow-up imaging.

RESULTS

Of 825 patients with CM-I and a syrinx, 251 (30.4%) were noted to have scoliosis present at the time of diagnosis. Forty-one (16.3%) of these patients underwent posterior fossa decompression and had follow-up imaging to assess for scoliosis. Twenty-three patients (56%) were female, the mean age at time of CM-I decompression was 10.0 years, and the mean follow-up duration was 1.3 years. Nine patients (22%) had stable curves, 16 (39%) showed improvement (> 5°), and 16 (39%) displayed curve progression (> 5°) during the follow-up period. Younger age at the time of decompression was associated with improvement in curve magnitude; for those with curves of ≤ 35°, 17% of patients younger than 10 years of age had curve progression compared with 64% of those 10 years of age or older (p = 0.008). There was no difference by age for those with curves > 35°. Tonsil position, baseline syrinx dimensions, and change in syrinx size were not associated with the change in curve magnitude. There was no difference in progression after surgery in patients who were also treated with a brace compared to those who were not treated with a brace for scoliosis.

CONCLUSIONS

In this cohort of patients with CM-I, a syrinx, and scoliosis, younger age at the time of decompression was associated with improvement in curve magnitude following surgery, especially in patients younger than 10 years of age with curves of ≤ 35°. Baseline tonsil position, syrinx dimensions, frontooccipital horn ratio, and craniocervical junction morphology were not associated with changes in curve magnitude after surgery.

ABBREVIATIONS

CM-I = Chiari malformation type I; pB = posterior basion; PFD = posterior fossa decompression.

OBJECTIVE

In patients with Chiari malformation type I (CM-I) and a syrinx who also have scoliosis, clinical and radiological predictors of curve regression after posterior fossa decompression are not well known. Prior reports indicate that age younger than 10 years and a curve magnitude < 35° are favorable predictors of curve regression following surgery. The aim of this study was to determine baseline radiological factors, including craniocervical junction alignment, that might predict curve stability or improvement after posterior fossa decompression.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and a syrinx (≥ 3 mm in width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°) in patients who underwent posterior fossa decompression and who also had follow-up imaging.

RESULTS

Of 825 patients with CM-I and a syrinx, 251 (30.4%) were noted to have scoliosis present at the time of diagnosis. Forty-one (16.3%) of these patients underwent posterior fossa decompression and had follow-up imaging to assess for scoliosis. Twenty-three patients (56%) were female, the mean age at time of CM-I decompression was 10.0 years, and the mean follow-up duration was 1.3 years. Nine patients (22%) had stable curves, 16 (39%) showed improvement (> 5°), and 16 (39%) displayed curve progression (> 5°) during the follow-up period. Younger age at the time of decompression was associated with improvement in curve magnitude; for those with curves of ≤ 35°, 17% of patients younger than 10 years of age had curve progression compared with 64% of those 10 years of age or older (p = 0.008). There was no difference by age for those with curves > 35°. Tonsil position, baseline syrinx dimensions, and change in syrinx size were not associated with the change in curve magnitude. There was no difference in progression after surgery in patients who were also treated with a brace compared to those who were not treated with a brace for scoliosis.

CONCLUSIONS

In this cohort of patients with CM-I, a syrinx, and scoliosis, younger age at the time of decompression was associated with improvement in curve magnitude following surgery, especially in patients younger than 10 years of age with curves of ≤ 35°. Baseline tonsil position, syrinx dimensions, frontooccipital horn ratio, and craniocervical junction morphology were not associated with changes in curve magnitude after surgery.

ABBREVIATIONS

CM-I = Chiari malformation type I; pB = posterior basion; PFD = posterior fossa decompression.

In Brief

The authors evaluated preoperative factors related to outcomes of scoliosis after posterior fossa decompression for patients with Chiari malformation–associated syringomyelia. This study will help inform which patients with scoliosis are likely to stabilize or progress after surgery.

Chiari malformation type I (CM-I), by definition, is characterized by downward displacement of the cerebellar tonsils at least 5 mm below the foramen magnum.18 A low tonsil position may disrupt normal CSF flow at the foramen magnum, resulting in syringomyelia.18,22,32 Scoliosis occurs at a higher rate in CM-I patients than in the general pediatric population and is the only presenting symptom in some cases.5,7,32 The overall incidence of scoliosis in the general pediatric population is 2%–4%; however, scoliosis is present in up to 30% of CM-I patients and up to 70% of CM-I patients who have an associated spinal cord syrinx.2,3,8,11,19 There are conflicting reports on the association between CM-I and scoliosis in the absence of a spinal cord syrinx.11,30,35 However, the association between syringomyelia, both idiopathic and in the setting of CM-I, and scoliosis is well established.3,7,8,10,23,33 Huebert and MacKinnon have suggested that the pathogenesis of scoliosis in the setting of syringomyelia may be a consequence of the destruction of cells in the medial nuclei of the spinal cord by the enlarging syrinx, resulting in denervation of truncal musculature.13 This distinct pathophysiology is supported by the atypical features of CM-I–related scoliosis in comparison to the idiopathic form, which includes a higher incidence of left-sided thoracic curves, juvenile onset before age 11 years, and rapid curve progression.7,26,29

The definitive surgical intervention for CM-I with or without syringomyelia is posterior fossa decompression (PFD) with or without duraplasty, although patients with a concomitant syrinx are more likely to undergo surgery than those with an isolated CM-I.5,6,25,32 A number of studies have reported varying rates of improvement or stabilization of scoliosis in patients who underwent PFD, with 18%–70% experiencing postsurgical curve progression that required additional intervention such as spinal fusion.2–4,8–10,14–17,19,27,28 Factors that have been variably associated with post-PFD progression include older age at the time of decompression, the degree of the initial scoliotic curve as indicated by the Cobb angle, the location of the curve, and syrinx reduction postsurgery.12 Of these, age at the time decompression and the severity of the curve before decompression are more consistently implicated as predictors of progression.1–4,8,9,15–17,20

In a meta-analysis of pediatric CM-I–associated scoliosis, Hwang et al. found that only age and the performance of a surgical intervention (PFD) were associated with improvement or stabilization of the curve.14 Given the rarity of the diagnosis, most studies of CM-I–associated scoliosis outcomes following PFD have been limited by sample size and thus may be underpowered to detect other patient characteristics predictive of progression. As Hwang et al. noted, there is inconsistent reporting of radiological parameters at presentation and during follow-up across studies, precluding definitive associations. In addition, the majority of studies have been performed at a single institution and may be sensitive to local referral patterns and treatment practices. Larger, multisite studies could allow for better prediction of scoliosis outcome after surgery.

The aim of this study was to determine baseline radiological factors, including craniocervical junction alignment, that might predict curve stability or improvement after PFD. In this study, we analyzed a large multicenter cohort of children with CM-I–related scoliosis and syringomyelia who underwent PFD and had a mean imaging follow-up period of 1.3 years.

Methods

Following Institutional Review Board approval at all participating centers, clinical, demographic, and imaging records for the first 854 patients enrolled in the Park-Reeves Syringomyelia Research Consortium database were reviewed. Enrollment dates ranged from June 2011 to May 2016 and included patients from 31 centers with ages up to 21 years old 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 was used in the study cohort. Retrospective subjects must have been treated within the last 15 years, have preoperative MRI scans, and have ≥ 5 years follow-up. Prospective subjects were enrolled starting July 1, 2011, and followed for at least 5 years at each site. Of the 825 patients in the study cohort, 313 were recruited in a retrospective fashion and 506 were recruited prospectively.31 Data from each site were entered into the central database by individual site coordinators and all entries were monitored and overseen remotely by a data monitor personnel at the lead site (Washington University in St. Louis). Review of medical and imaging records identified 825 patients who underwent PFD and who had a cerebellar tonsil position ≥ 5 mm below the foramen magnum, syrinx width (maximum axial diameter of the syrinx cavity) ≥ 3 mm, and complete data regarding clinical history, examination findings, and operative parameters. Review of radiographs and MR images for these patients identified 251 with scoliosis present at the time of their CM-I diagnosis, with scoliosis defined as a coronal curve of at least 10°. Curves were measured according to the guidelines from the Spinal Deformity Study Group’s Radiographic Measurement Manual by O’Brien et al.21 Of these, 41 patients underwent PFD and had at least 1 follow-up image with a mean interval of 2 years before undergoing spinal fusion.

Demographic information analyzed for an association with change in curve after PFD included sex and age at the time of surgery. Radiological parameters assessed for their association with curve progression included Cobb angle (C.A., J.I.G.), location of greatest curve (C.A.), and MRI parameters (Jerrel Rutlin), such as tonsil position, syrinx length, syrinx width, syrinx location, posterior basion to C2 (pB-C2) distance, clivoaxial angle, and frontooccipital horn ratio.31 Change in syrinx dimensions (width and length) was assessed based on pre- and postsurgical imaging. Curve progression was defined as a 5° or greater increase, with curve improvement defined as a 5° or greater improvement in curve.34 We stratified age as less than or greater than 10 years and curve degree less than or greater than 35°. An age cutoff of 10 years and curve summary statistics were estimated by proportions, means, medians, minimum, maximum, and standard deviations. Pearson’s correlations were calculated between continuous variables. Probability values were calculated by general linear model methods between variables for continuous variables with multiple comparisons done by a Tukey’s test where appropriate. Probability values using chi-square tests were used for proportions, and categorical variables were used for comparison by groups.

Results

In this postsurgical follow-up cohort, 23 patients (56%) were female. Patient age ranged from 2.6 to 16.1 years at diagnosis, with a mean age of 9.8 years. The mean age at decompression surgery was 10.0 years. The average radiographic follow-up duration after decompression was 2.03 years (range 0.2–4.86 years) and 10 patients ultimately underwent spinal fusion. Curves remained stable in 9 patients (22%), with changes in Cobb angle of < 5° in either direction. Sixteen patients (39%) improved, experiencing a decrease in Cobb angle of at least 5°. In 16 patients (39%) curves progressed, as defined by a postoperative increase in the Cobb angle of ≥ 5° (Table 1). There was no difference in sex distribution between the patients whose curves remained stable (male 17%, female 29%), improved (male 44%, female 35%), and progressed (male 39%, female 39%) (p = 0.723). The mean ages at time of decompression for the patients whose curves remained stable, improved, and progressed were 11.1, 7.9, and 11.5 years, respectively (Table 2). Patients whose curves improved were significantly younger than those whose curves remained stable or progressed (improved vs stable, p = 0.03; improved vs progressed, p = 0.01). Additionally, there was a positive correlation between age at CM-I diagnosis and change in curve following surgery (p = 0.009) (Fig. 1). The mean Cobb angle at presentation was 33.4° for the patients whose curves remained stable, 28.4° for those whose curves improved, and 36.1° for those whose curves progressed (Table 2). There was no association between the Cobb angle at time of decompression and improvement or worsening of the curve. However, there was a trend toward curve improvement in cases that involved smaller baseline curves. Specifically for those with curves ≤ 35°, 17% of patients < 10 years of age had curve progression compared with 64% of those ≥ 10 years of age (p = 0.008), and there was no difference in progression by age for those with curves > 35°. The distribution of the locations of the curves with the greatest Cobb angle (thoracic, thoracolumbar, and lumbar) was not different among the 3 groups. Similarly, the presence of a left-sided thoracic curve was not associated with scoliosis progression or improvement after decompression. There was no difference in curve progression after surgery in patients who were also treated with a brace compared to those who were not treated with a brace for scoliosis.

TABLE 1.

Summary of demographic and postoperative data for 41 patients with CM-I, syringomyelia, and scoliosis who underwent PFD

VariableValue (%)
Sex
 Male18 (43.9%)
 Female23 (56.1%)
Age at diagnosis, yrs
 Minimum2.6
 Maximum16.1
 Mean9.8
 Median10.2
Follow-up, yrs
 Minimum0.2
 Maximum4.9
 Mean2.0
 Median1.8
Curve condition
 Stable (<4°)9 (22%)
 Improved (↓ >5°)16 (39%)
 Progressed (↑ ≥5°)16 (39%)

↓ = decreased; ↑ = increased.

TABLE 2.

Clinical and radiological variables associated with curve progression

Curve
VariableStableImprovedProgressedp Value
No.91616
Sex0.723
 Male3 (16.7%)8 (44.4%)7 (38.9%)
 Female6 (29.1%)8 (34.8%)9 (39.1%)
Age at decompression, yrs0.005
 Mean11.17.911.5
 Minimum5.13.73.4
 Maximum14.616.315.4
Mean Cobb angle, °33.428.436.10.165
Change in degree of curve<0.001
 Mean0.1−13.712.4
 Minimum−4.0−29.05.0
 Maximum3.0−5.030.0
Tonsillar descent, mm*0.223
 Mean12.811.99.8
 Minimum8.05.35.0
 Maximum23.019.018.0
Syrinx diameter, mm*0.371
 Mean7.29.19.1
 Minimum3.03.03.0
 Maximum11.014.018.0
Syrinx change, mm*0.097
 Mean−2.1−5.7−4.6
 Minimum0.6−11.3−14.0
 Maximum1.0−2.02.0
Percentage of syrinx change0.066
 Mean−30%−60%−50%
 Minimum−75%−90%−90%
 Maximum17%−20%15%
Clivoaxial angle, °*0.872
 Mean147.7146.1148.1
 Minimum131.0131.0123.0
 Maximum165.0170.0169.0
Frontooccipital horn ratio0.478
 Mean0.290.300.31
 Minimum0.270.250.22
 Maximum0.340.320.37
Syrinx levels0.137
 Mean8.811.313.1
 Minimum328
 Maximum121817

Measured in 8, 15, and 12 patients with stable, improved, and progressive post-PFD curves, respectively.

Measured in 6, 9, and 11 patients with stable, improved, and progressive post-PFD curves, respectively.

Denotes the number of vertebral levels the syrinx covers. Measured in 9, 16, and 5 patients with stable, improved, and progressive post-PFD curves, respectively.

FIG. 1.
FIG. 1.

Change in curve after surgery versus age at the time of CM-I decompression (p = 0.009).

There was no difference in the distribution of cervical syrinxes between the patients whose curves were stable, improved, or progressed after surgery. No association was found between syrinx width or syrinx length at diagnosis and change in curve after surgery. The mean change in syrinx width was −4.5 ± 3.6 mm throughout the follow-up period. Overall, there was no association between change in syrinx width and curve progression among the 3 groups, but patients with curve improvement had a greater decrease in syrinx width after surgery compared to patients with stable curves (−5.7° [60% decrease] vs −2.1° [30% decrease]; p = 0.03). There was no relationship between curve progression and initial syrinx length. Furthermore, the frequency of repeat CM-I decompression was equal among the 3 outcome groups. Clinicoradiological parameters at presentation, such as pB-C2 distance, tonsil position, clivoaxial angle, and frontal occipital horn ratio, were similar among groups and were not associated with change in curve after decompression.

Discussion

In this multicenter cohort of CM-I-syrinx patients with scoliosis, we found that younger age at the time of decompression is associated with a postoperative improvement in scoliosis, particularly for those with curves of ≤ 35°. Radiological characteristics such as baseline tonsil position, syrinx size/location, and craniocervical junction morphology did not predict curve progression following PFD. Older age at decompression and a greater curve magnitude at the time of surgery are two commonly cited predictors of post-PFD curve progression.3,4,8,9,14–17,34 In one study, 71% of patients younger than 10 years of age had curve improvement after decompression, compared with only 11% of those older than 10 years of age,27 while in a separate study the mean age of those whose curves improved was 8 years compared to 14.5 years for those whose curves progressed.8 Three additional studies concluded that early decompression predicted improvement in curve magnitudes or reduced the likelihood of needing eventual spinal fusion, advocating for surgical intervention before the age of 10 years.3,4,9 Zhu et al., using a 54-patient cohort, identified a cutoff of 10.5 years of age as the inflection point for curve improvement/stabilization versus progression after decompression.34 Our results are consistent with these prior reports, indicating that younger age (< 10 years) is associated with a decreased risk of curve progression following decompression.

The severity of the curve at the time of decompression is a known predictor of curve-related outcome after PFD.2,9,10,16 Various degrees of curve cutoffs that stratify patients into those at risk for progression vary from 30° to 40°.3–5,18,21,31 The mean presenting curve degree for those whose scoliosis progressed in our cohort was 39°, which is in line with these studies, and although we saw a trend toward stabilization or improvement in patients with smaller baseline curves, this observation was not statistically significant. However, after stratifying risk of progression by age, we found that significantly fewer patients with curves < 35° who were younger than 10 years of age had post-PFD progression than patients who were 10 years of age and older, consistent with prior reports.

In contrast are several reports that do not support curve magnitude as a predictor of outcome after surgery, including a meta-analysis whose authors found that curve magnitude was not associated with post-decompression curve dynamics.14,19,27 In our study, the mean Cobb angle was not significantly different when comparing patients with an improved or stable curve and those with curve progression. However, analyzing the group as a whole, without accounting for age, may explain the lack of difference seen in risk of progression based on initial curve magnitude when comparing our study with prior studies.

We evaluated the significance of other clinicoradiological parameters that have been less frequently implicated as predictors of curve change after PFD. Syrinx size at presentation and postsurgical syrinx resolution have been cited less consistently as predictors of scoliosis evolution following decompression. Attenello et al.2 noted that failure of the syrinx to decrease in size was associated with a fourfold increase in the likelihood of scoliosis progression, similar to other studies that found a change in syrinx size was associated with improvement of the curve.16,32 In our cohort, none of the following factors were associated with a change in curves during the follow-up period: tonsil position, syrinx location, syrinx size at presentation, or change in syrinx size after decompression. Neither clivoaxial angle nor pB-C2 line was associated with post-decompression curve changes in our study cohort. However, Ravindra et al. noted that a lower clivoaxial angle was independently associated with a need for later fusion after CM-I decompression in a cohort of patients with CM-I and scoliosis followed long term.24 We did not find an association between left-sided thoracic curves and the increased likelihood of curve improvement after surgery, as was noted by Sengupta et al.27

Our study has several limitations. First and foremost, while we used a large, detailed, multiinstitutional, retrospective and prospective database on children with CM-I and syringomyelia, it was not designed specifically to answer the question this study poses. Second, despite our cohort’s being one of the larger ones to address the question of scoliosis progression following PFD, the sample size may still be too small to provide sufficient statistical power to detect other important associations. Third, the mean follow-up duration (2 years) was short. As a number of the younger patients may not have reached skeletal maturity at the time of data collection for this study, some patients’ curves may have progressed after the follow-up interval. Fourth, we were only able to confirm scoliosis in a limited number of patients, and therefore this may have selected for more severe curves or for patients in whom dedicated imaging was recommended. Lastly, there was limited follow-up imaging in some patients, further reducing the statistical power to detect the association between some clinicoradiological parameters and curve dynamics after surgery. As stated, the number of patients with follow-up imaging in this multiinstitutional cohort is a significant limitation. In addition, all patients in this cohort had CM-I–associated syringomyelia, and therefore we were unable to evaluate scoliosis outcomes in CM-I patients without a syrinx.

Conclusions

In the present cohort of patients with CM-I, syringomyelia, and scoliosis, younger age at the time of decompression was associated with postsurgical curve improvement, especially for patients younger than 10 years of age with curves 35° or less. Baseline tonsil position, syrinx characteristics, frontooccipital horn ratio, and craniocervical junction deformity were not associated with curve progression or regression after surgery.

Acknowledgments

We would like to acknowledge Sam and Betsy Reeves and their family and friends for their generosity in supporting the Park-Reeves Syringomyelia Research Consortium. We would like to thank Michael Lehmkuhl and Jerrel Rutlin for their assistance in database management. We would also like to thank the Park-Reeves Syringomyelia Research Consortium members.

The Park-Reeves Syringomyelia Research Consortium consists of the following clinical centers and investigators: St. Louis Children’s Hospital, Washington University in St. Louis (D. Limbrick, T.S. Park, J. Strahle, R. Dacey, M. Kelly, M. Smyth, J. Shimony, J. Rutlin); Monroe Carell Jr. Children’s Hospital of Vanderbilt University (C. Shannon, J. Wellons, C. Bonfield); Stead Family Children’s Hospital, University of Iowa (A. Menezes, J. Torner); Children’s Hospital of Wisconsin (B. Iskander, R. Ahmed); Texas Children’s Hospital, Baylor College of Medicine (W. Whitehead, R. Dauser); Children’s Hospital of Colorado, University of Colorado (B. O’Neill, T. Hankinson); C.S. Mott Children’s Hospital, University of Michigan (C. Maher); Brenner Children’s Hospital, Wake Forest University (D. Couture); Phoenix Children’s Hospital, Barrow Neurological Institute (P.D. Adelson); Children’s Hospital at Dartmouth-Hitchcock, Dartmouth School of Medicine (D. Bauer); Mayo Clinic (D. Daniels); Primary Children’s Hospital, University of Utah (D. Brockmeyer); Johns Hopkins Children’s Center, Johns Hopkins School of Medicine (E. Jackson); Cincinnati Children’s Hospital, University of Cincinnati (F. Mangano, K. Bierbrauer); Lucile Packard Children’s Hospital, Stanford University School of Medicine (G. Grant); All Children’s Hospital, Johns Hopkins University School of Medicine (G. Tuite); Children’s Hospital Los Angeles, Keck School of Medicine at USC (J.D. McComb, M. Krieger); Children’s Hospital of Pennsylvania, University of Pennsylvania School of Medicine (G. Heuer); Arkansas Children’s Hospital, University of Arkansas School of Medicine (G. Albert); Arnold Palmer Hospital for Children, University of Central Florida School of Medicine (G. Olavarria, S. Elbabaa); Duke Children’s Hospital, Duke University School of Medicine (H. Fuchs); Children’s of Alabama, University of Alabama at Birmingham (J. Johnston, W. J. Oakes); Komansky Children’s Hospital, Weill Cornell School of Medicine (J. Greenfield); Nationwide Children’s Hospital, The Ohio State University School of Medicine (J. Leonard); Riley Children’s Hospital, University of Indiana School of Medicine (J. Smith); Nicklaus Children’s Hospital, University of Miami School of Medicine (J. Ragheb); Children’s Hospital of Atlanta, Emory University School of Medicine (J. Chern); Doernbecher Children’s Hospital, Oregon Health and Sciences School of Medicine (L. Baird, N. Selden); University of British Columbia Department of Neurosurgery, Division of Pediatric Neurosurgery (M. Tamber); University of Texas Health Science Center at Houston, Memorial Hermann (M. Shah); Penn State Health Milton S. Hershey Medical Center (M. Iantosca); Le Bonheur Children’s Hospital, Semmes Murphey (M. Muhlbauer, N. Kahn); University of Florida Health, Division of Pediatric Neurosurgery (P. Aldana); Medical University of South Carolina, Division of Pediatric Neurosurgery (R. Eskandari); Columbia University Vagelos College of Physicians and Surgeons (R. Anderson); University of Washington Department of Neurological Surgery (R. Ellenbogen); Children’s National Medical Center, Division of Neurosurgery (R. Keating); Carolina Neurosurgery and Spine Associates (S. Wait, M. Van Poppel); University of Vermont Medical Center, Department of Neurological Surgery (S. Durham); Dell Children’s Medical Center of Dell Seton Medical Center at the University of Texas (T. George); University of Oklahoma Department of Neurological Surgery (T. Mapstone, N. Gross); Lurie Children’s Hospital of Northwestern University, Division of Pediatric Neurosurgery (T. Alden).

Disclosures

Dr. Kelly reports receiving support for a non–study-related clinical or research effort that he oversees from DePuy Synthes. Dr. Limbrick reports receiving support for a non–study-related clinical or research effort that he oversees from Microbot, Inc., and from Medtronic.

Author Contributions

Conception and design: Strahle, Limbrick. Acquisition of data: Strahle, Taiwo, Averill, Gewirtz, Shannon, Bonfield, Tuite, Bethel-Anderson, Anderson, Kelly, Shimony, Smyth, Park, Limbrick. Analysis and interpretation of data: Strahle, Taiwo, Averill, Torner, Tuite, Shimony, Limbrick. Drafting the article: Strahle, Taiwo, Limbrick. Critically revising the article: Strahle, Taiwo, Averill, Torner, Bonfield, Tuite, Bethel-Anderson, Anderson, Kelly, Shimony, Dacey, Smyth, Park, Limbrick. Reviewed submitted version of manuscript: Strahle, Taiwo, Averill, Torner, Shannon, Bonfield, Tuite, Bethel-Anderson, Anderson, Kelly, Shimony, Dacey, Smyth, Park, Limbrick. Approved the final version of the manuscript on behalf of all authors: Strahle. Statistical analysis: Torner. Administrative/technical/material support: Strahle, Taiwo, Averill, Gewirtz, Bethel-Anderson, Limbrick. Study supervision: Limbrick.

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    Huebert HT, MacKinnon WB: Syringomyelia and scoliosis. J Bone Joint Surg Br 51:338343, 1969

  • 14

    Hwang SW, Samdani AF, Jea A, Raval A, Gaughan JP, Betz RR, et al. : Outcomes of Chiari I-associated scoliosis after intervention: a meta-analysis of the pediatric literature. Childs Nerv Syst 28:12131219, 2012

    • Search Google Scholar
    • Export Citation
  • 15

    Krieger MD, Falkinstein Y, Bowen IE, Tolo VT, McComb JG: Scoliosis and Chiari malformation Type I in children. J Neurosurg Pediatr 7:2529, 2011

    • Search Google Scholar
    • Export Citation
  • 16

    Lee S, Wang KC, Cheon JE, Phi JH, Lee JY, Cho BK, et al. : Surgical outcome of Chiari I malformation in children: clinico-radiological factors and technical aspects. Childs Nerv Syst 30:613623, 2014

    • Search Google Scholar
    • Export Citation
  • 17

    Mackel CE, Cahill PJ, Roguski M, Samdani AF, Sugrue PA, Kawakami N, et al. : Factors associated with spinal fusion after posterior fossa decompression in pediatric patients with Chiari I malformation and scoliosis. J Neurosurg Pediatr 25:737743, 2016

    • Search Google Scholar
    • Export Citation
  • 18

    Milhorat TH, Chou MW, Trinidad EM, Kula RW, Mandell M, Wolpert C, et al. : Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients. Neurosurgery 44:10051017, 1999

    • Search Google Scholar
    • Export Citation
  • 19

    Muhonen MG, Menezes AH, Sawin PD, Weinstein SL: Scoliosis in pediatric Chiari malformations without myelodysplasia. J Neurosurg 77:6977, 1992

    • Search Google Scholar
    • Export Citation
  • 20

    Nagib MG: An approach to symptomatic children (ages 4–14 years) with Chiari type I malformation. Pediatr Neurosurg 21:3135, 1994

  • 21

    O’Brien MF, Kuklo TR, Blanke KM, Lenke LG: Radiographic Measurement Manual. Spinal Deformity Study Group (SDSG). Memphis: Medtronic Sofamor Danek USA, 2008 (https://www.oref.org/docs/default-source/default-document-library/sdsg-radiographic-measuremnt-manual.pdf?sfvrsn=2&sfvrsn=2) [Accessed January 24, 2020]

    • Search Google Scholar
    • Export Citation
  • 22

    Oldfield EH, Muraszko K, Shawker TH, Patronas NJ: Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment. J Neurosurg 80:315, 1994

    • Search Google Scholar
    • Export Citation
  • 23

    Ozerdemoglu RA, Denis F, Transfeldt EE: Scoliosis associated with syringomyelia: clinical and radiologic correlation. Spine (Phila Pa 1976) 28:14101417, 2003

    • Search Google Scholar
    • Export Citation
  • 24

    Ravindra VM, Onwuzulike K, Heller RS, Quigley R, Smith J, Dailey AT, et al. : Chiari-related scoliosis: a single-center experience with long-term radiographic follow-up and relationship to deformity correction. J Neurosurg Pediatr 21:185189, 2018

    • Search Google Scholar
    • Export Citation
  • 25

    Rocque BG, George TM, Kestle J, Iskandar BJ: Treatment practices for Chiari malformation type I with syringomyelia: results of a survey of the American Society of Pediatric Neurosurgeons. J Neurosurg Pediatr 8:430437, 2011

    • Search Google Scholar
    • Export Citation
  • 26

    Schwend RM, Hennrikus W, Hall JE, Emans JB: Childhood scoliosis: clinical indications for magnetic resonance imaging. J Bone Joint Surg Am 77:4653, 1995

    • Search Google Scholar
    • Export Citation
  • 27

    Sengupta DK, Dorgan J, Findlay GF: Can hindbrain decompression for syringomyelia lead to regression of scoliosis? Eur Spine J 9:198201, 2000

    • Search Google Scholar
    • Export Citation
  • 28

    Sha S, Zhu Z, Lam TP, Sun X, Qian B, Jiang J, et al. : Brace treatment versus observation alone for scoliosis associated with Chiari I malformation following posterior fossa decompression: a cohort study of 54 patients. Eur Spine J 23:12241231, 2014

    • Search Google Scholar
    • Export Citation
  • 29

    Spiegel DA, Flynn JM, Stasikelis PJ, Dormans JP, Drummond DS, Gabriel KR, et al. : Scoliotic curve patterns in patients with Chiari I malformation and/or syringomyelia. Spine (Phila Pa 1976) 28:21392146, 2003

    • Search Google Scholar
    • Export Citation
  • 30

    Strahle J, Smith BW, Martinez M, Bapuraj JR, Muraszko KM, Garton HJ, et al. : The association between Chiari malformation Type I, spinal syrinx, and scoliosis. J Neurosurg Pediatr 15:607611, 2015

    • Search Google Scholar
    • Export Citation
  • 31

    Strahle JM, Taiwo R, Averill C, Torner J, Shannon CN, Bonfield CM, et al. : Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium. J Neurosurg Pediatr 24:520527, 2019

    • Search Google Scholar
    • Export Citation
  • 32

    Tubbs RS, McGirt MJ, Oakes WJ: Surgical experience in 130 pediatric patients with Chiari I malformations. J Neurosurg 99:291296, 2003

    • Search Google Scholar
    • Export Citation
  • 33

    Zhu Z, Sha S, Chu WC, Yan H, Xie D, Liu Z, et al. : Comparison of the scoliosis curve patterns and MRI syrinx cord characteristics of idiopathic syringomyelia versus Chiari I malformation. Eur Spine J 25:517525, 2016

    • Search Google Scholar
    • Export Citation
  • 34

    Zhu Z, Wu T, Zhou S, Sun X, Yan H, Sha S, et al. : Prediction of curve progression after posterior fossa decompression in pediatric patients with scoliosis secondary to Chiari malformation. Spine Deform 1:2532, 2013

    • Search Google Scholar
    • Export Citation
  • 35

    Zhu Z, Yan H, Han X, Jin M, Xie D, Sha S, et al. : Radiological features of scoliosis in Chiari I malformation without syringomyelia. Spine (Phila Pa 1976) 41:E276E281, 2016

    • Search Google Scholar
    • Export Citation

Contributor Notes

Correspondence Jennifer M. Strahle: Washington University School of Medicine, St. Louis Children’s Hospital, St. Louis, MO. strahlej@wustl.edu.

INCLUDE WHEN CITING Published online April 10, 2020; DOI: 10.3171/2020.1.PEDS18755.

Disclosures Dr. Kelly reports receiving support for a non–study-related clinical or research effort that he oversees from DePuy Synthes. Dr. Limbrick reports receiving support for a non–study-related clinical or research effort that he oversees from Microbot, Inc., and from Medtronic.

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    Change in curve after surgery versus age at the time of CM-I decompression (p = 0.009).

  • 1

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    Brockmeyer D, Gollogly S, Smith JT: Scoliosis associated with Chiari 1 malformations: the effect of suboccipital decompression on scoliosis curve progression: a preliminary study. Spine (Phila Pa 1976) 28:25052509, 2003

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    Emery E, Redondo A, Rey A: Syringomyelia and Arnold Chiari in scoliosis initially classified as idiopathic: experience with 25 patients. Eur Spine J 6:158162, 1997

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    Eule JM, Erickson MA, O’Brien MF, Handler M: Chiari I malformation associated with syringomyelia and scoliosis: a twenty-year review of surgical and nonsurgical treatment in a pediatric population. Spine (Phila Pa 1976) 27:14511455, 2002

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  • 9

    Flynn JM, Sodha S, Lou JE, Adams SB Jr, Whitfield B, Ecker ML, et al. : Predictors of progression of scoliosis after decompression of an Arnold Chiari I malformation. Spine (Phila Pa 1976) 29:286292, 2004

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    Ghanem IB, Londono C, Delalande O, Dubousset JF: Chiari I malformation associated with syringomyelia and scoliosis. Spine (Phila Pa 1976) 22:13131318, 1997

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    • Export Citation
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    Godzik J, Dardas A, Kelly MP, Holekamp TF, Lenke LG, Smyth MD, et al. : Comparison of spinal deformity in children with Chiari I malformation with and without syringomyelia: matched cohort study. Eur Spine J 25:619626, 2016

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  • 12

    Godzik J, Holekamp TF, Limbrick DD, Lenke LG, Park TS, Ray WZ, et al. : Risks and outcomes of spinal deformity surgery in Chiari malformation, Type 1, with syringomyelia versus adolescent idiopathic scoliosis. Spine J 15:20022008, 2015

    • Search Google Scholar
    • Export Citation
  • 13

    Huebert HT, MacKinnon WB: Syringomyelia and scoliosis. J Bone Joint Surg Br 51:338343, 1969

  • 14

    Hwang SW, Samdani AF, Jea A, Raval A, Gaughan JP, Betz RR, et al. : Outcomes of Chiari I-associated scoliosis after intervention: a meta-analysis of the pediatric literature. Childs Nerv Syst 28:12131219, 2012

    • Search Google Scholar
    • Export Citation
  • 15

    Krieger MD, Falkinstein Y, Bowen IE, Tolo VT, McComb JG: Scoliosis and Chiari malformation Type I in children. J Neurosurg Pediatr 7:2529, 2011

    • Search Google Scholar
    • Export Citation
  • 16

    Lee S, Wang KC, Cheon JE, Phi JH, Lee JY, Cho BK, et al. : Surgical outcome of Chiari I malformation in children: clinico-radiological factors and technical aspects. Childs Nerv Syst 30:613623, 2014

    • Search Google Scholar
    • Export Citation
  • 17

    Mackel CE, Cahill PJ, Roguski M, Samdani AF, Sugrue PA, Kawakami N, et al. : Factors associated with spinal fusion after posterior fossa decompression in pediatric patients with Chiari I malformation and scoliosis. J Neurosurg Pediatr 25:737743, 2016

    • Search Google Scholar
    • Export Citation
  • 18

    Milhorat TH, Chou MW, Trinidad EM, Kula RW, Mandell M, Wolpert C, et al. : Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients. Neurosurgery 44:10051017, 1999

    • Search Google Scholar
    • Export Citation
  • 19

    Muhonen MG, Menezes AH, Sawin PD, Weinstein SL: Scoliosis in pediatric Chiari malformations without myelodysplasia. J Neurosurg 77:6977, 1992

    • Search Google Scholar
    • Export Citation
  • 20

    Nagib MG: An approach to symptomatic children (ages 4–14 years) with Chiari type I malformation. Pediatr Neurosurg 21:3135, 1994

  • 21

    O’Brien MF, Kuklo TR, Blanke KM, Lenke LG: Radiographic Measurement Manual. Spinal Deformity Study Group (SDSG). Memphis: Medtronic Sofamor Danek USA, 2008 (https://www.oref.org/docs/default-source/default-document-library/sdsg-radiographic-measuremnt-manual.pdf?sfvrsn=2&sfvrsn=2) [Accessed January 24, 2020]

    • Search Google Scholar
    • Export Citation
  • 22

    Oldfield EH, Muraszko K, Shawker TH, Patronas NJ: Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment. J Neurosurg 80:315, 1994

    • Search Google Scholar
    • Export Citation
  • 23

    Ozerdemoglu RA, Denis F, Transfeldt EE: Scoliosis associated with syringomyelia: clinical and radiologic correlation. Spine (Phila Pa 1976) 28:14101417, 2003

    • Search Google Scholar
    • Export Citation
  • 24

    Ravindra VM, Onwuzulike K, Heller RS, Quigley R, Smith J, Dailey AT, et al. : Chiari-related scoliosis: a single-center experience with long-term radiographic follow-up and relationship to deformity correction. J Neurosurg Pediatr 21:185189, 2018

    • Search Google Scholar
    • Export Citation
  • 25

    Rocque BG, George TM, Kestle J, Iskandar BJ: Treatment practices for Chiari malformation type I with syringomyelia: results of a survey of the American Society of Pediatric Neurosurgeons. J Neurosurg Pediatr 8:430437, 2011

    • Search Google Scholar
    • Export Citation
  • 26

    Schwend RM, Hennrikus W, Hall JE, Emans JB: Childhood scoliosis: clinical indications for magnetic resonance imaging. J Bone Joint Surg Am 77:4653, 1995

    • Search Google Scholar
    • Export Citation
  • 27

    Sengupta DK, Dorgan J, Findlay GF: Can hindbrain decompression for syringomyelia lead to regression of scoliosis? Eur Spine J 9:198201, 2000

    • Search Google Scholar
    • Export Citation
  • 28

    Sha S, Zhu Z, Lam TP, Sun X, Qian B, Jiang J, et al. : Brace treatment versus observation alone for scoliosis associated with Chiari I malformation following posterior fossa decompression: a cohort study of 54 patients. Eur Spine J 23:12241231, 2014

    • Search Google Scholar
    • Export Citation
  • 29

    Spiegel DA, Flynn JM, Stasikelis PJ, Dormans JP, Drummond DS, Gabriel KR, et al. : Scoliotic curve patterns in patients with Chiari I malformation and/or syringomyelia. Spine (Phila Pa 1976) 28:21392146, 2003

    • Search Google Scholar
    • Export Citation
  • 30

    Strahle J, Smith BW, Martinez M, Bapuraj JR, Muraszko KM, Garton HJ, et al. : The association between Chiari malformation Type I, spinal syrinx, and scoliosis. J Neurosurg Pediatr 15:607611, 2015

    • Search Google Scholar
    • Export Citation
  • 31

    Strahle JM, Taiwo R, Averill C, Torner J, Shannon CN, Bonfield CM, et al. : Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium. J Neurosurg Pediatr 24:520527, 2019

    • Search Google Scholar
    • Export Citation
  • 32

    Tubbs RS, McGirt MJ, Oakes WJ: Surgical experience in 130 pediatric patients with Chiari I malformations. J Neurosurg 99:291296, 2003

    • Search Google Scholar
    • Export Citation
  • 33

    Zhu Z, Sha S, Chu WC, Yan H, Xie D, Liu Z, et al. : Comparison of the scoliosis curve patterns and MRI syrinx cord characteristics of idiopathic syringomyelia versus Chiari I malformation. Eur Spine J 25:517525, 2016

    • Search Google Scholar
    • Export Citation
  • 34

    Zhu Z, Wu T, Zhou S, Sun X, Yan H, Sha S, et al. : Prediction of curve progression after posterior fossa decompression in pediatric patients with scoliosis secondary to Chiari malformation. Spine Deform 1:2532, 2013

    • Search Google Scholar
    • Export Citation
  • 35

    Zhu Z, Yan H, Han X, Jin M, Xie D, Sha S, et al. : Radiological features of scoliosis in Chiari I malformation without syringomyelia. Spine (Phila Pa 1976) 41:E276E281, 2016

    • Search Google Scholar
    • Export Citation

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