Scoliosis in children with Chiari I-related syringomyelia

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Patients With Chiari Malformation: Diagnosis

BACKGROUND

Chiari I malformation (CIM) is characterized by descent of the cerebellar tonsils through the foramen magnum, potentially causing symptoms from compression or obstruction of the flow of cerebrospinal fluid. Diagnosis and treatment of CIM is varied, and guidelines produced through systematic review may be helpful for clinicians.

OBJECTIVE

To perform a systematic review of the medical literature to answer specific questions on the diagnosis and treatment of CIM.

METHODS

PubMed and Embase were queried between 1946 and January 23, 2021, using the search strategies provided in Appendix I of the full guidelines.

RESULTS

The literature search yielded 567 abstracts, of which 151 were selected for full-text review, 109 were then rejected for not meeting the inclusion criteria or for being off-topic, and 42 were included in this systematic review.

CONCLUSION

Three Grade C recommendations were made based on Level III evidence. The full guidelines can be seen online at https://www.cns.org/guidelines/browse-guidelines-detail/1-imaging .

Treatment of Chiari Malformation and Concomitant Paediatric Scoliosis Long-Term Follow-Up in One Major Referral Centre in the UK

OBJECTIVE

Paediatric scoliosis (PS) and Chiari malformation type 1 (CM-1) have been reported to be associated with each other. Scoliosis curvature is a common finding among patients operated for CM-1, and curve development has been related to it. We report a cohort of PS and CM-1 patients managed with posterior fossa and upper cervical decompression (PFUCD) by a single surgeon, with an average of two years of follow-up.

METHODS

We present a retrospective cohort in a single referral centre for patients with CM-1 and PS.

RESULTS

From 2011 to 2018, we identified fifteen patients with CM-1 and PS; eleven underwent PFUCD, ten had symptomatic CM-1, and one had asymptomatic CM-1 but showed curve progression. The remaining four CM-1 patients were asymptomatic and were hence treated conservatively. The average follow-up post-PFUCD was 26.2 months. Scoliosis surgery was performed in seven cases; six patients underwent PFUCD prior to the scoliosis correction. One scoliosis case underwent surgery in the presence of mild CM-1 treated conservatively. The remaining four cases were scheduled for scoliosis correction surgery, while three were managed conservatively, with one case lost to follow-up. The average time between PFUCD and scoliosis surgery was 11 months. None of the cases had intraoperative neuromonitoring alerts or perioperative neurological complications.

CONCLUSION

CM-1 with concomitant scoliosis can be found. Symptomatic CM-1 might require surgery, but as we discovered, PFUCD had negligible effect on curve progression and the future need for scoliosis surgery.

Socioeconomic and demographic factors in the diagnosis and treatment of Chiari malformation type I and syringomyelia

OBJECTIVE

The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM).

METHODS

The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes.

RESULTS

A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively).

CONCLUSIONS

Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

Longitudinal scoliosis behavior in Chiari malformation with and without syringomyelia

OBJECTIVE

The objective of this study was to understand the natural history of scoliosis in patients with Chiari malformation type I (CM-I) with and without syringomyelia.

METHODS

A retrospective review of data was conducted. Patients with CM-I were identified from a cohort of 14,118 individuals age 18 years or younger who had undergone MRI over an 11-year period at the University of Michigan. Patients eligible for study inclusion had a coronal curve ≥ 10° on radiography, associated CM-I with or without syringomyelia, and at least 1 year of clinical follow-up prior to any surgery. Curve magnitude at initial diagnosis, prior to posterior fossa decompression (PFD; if applicable), and at the last follow-up (prior to any surgical correction of scoliosis) was recorded, and clinical and radiographic characteristics were noted. The change in curve magnitude by 10° was defined as curve progression (increase by 10°) or regression (decrease by 10°).

RESULTS

Forty-three patients met the study inclusion criteria and were analyzed. About one-third (35%) of the patients presented with symptoms attributed to their CM-I. The mean degree of scoliosis at presentation was 32.6° ± 17.7°. Twenty-one patients (49%) had an associated syrinx. The mean tonsil position below the level of the foramen magnum was 9.8 ± 5.8 mm. Patients with a syrinx were more likely to have a curve > 20° (86% vs 41%, p = 0.002). Curve magnitude remained stable (≤ ±10°) in 77% of patients (33/43), progressed in 16% (7/43), and regressed in 7% (3/43). Mean age was higher (14.8 ± 0.59 years) among patients with regressed curves (p = 0.026). All regressed curves initially measured ≤ 20° (mean 14° ± 5.3°), and none of the patients with regressed curves had a syrinx. The change in curve magnitude was statistically similar in patients with (7.32° ± 17.7°) and without (5.32° ± 15.8°) a syrinx (p = 0.67). After a mean follow-up of 3.13 ± 2.04 years prior to surgery, 27 patients (63%) ultimately underwent posterior fossa or scoliosis correction surgery. For those who eventually underwent PFD only, the rate of change in curve magnitude prior to surgery was 0.054° ± 0.79°. The rate of change in curve magnitude was statistically similar before (0.054° ± 0.79°) and after (0.042° ± 0.33°) surgery (p = 0.45) for patients who underwent PFD surgery only.

CONCLUSIONS

The natural history of scoliosis in the presence of CM-I is variable, though most curves remained stable. All curves that regressed were ≤ 20° at initial diagnosis, and most patients in such cases were older at scoliosis diagnosis. Patients who underwent no surgery or PFD only had similar profiles for the change in curve magnitude, which remained relatively stable overall, as compared to patients who underwent PFD and subsequent fusion, who demonstrated curve progression. Among the patients with a syrinx, no curves regressed, most remained stable, and some progressed. Understanding this variability is a first step toward building a prediction model for outcomes for these patients.

Delayed Postoperative Spinal Cord Ischemia After Posterior Spinal Fusion in a Pediatric Patient with Syrinx and Decompressed Chiari: A Case Report

CASE

We present a case of delayed postoperative neurologic deficits 1 day after posterior spinal fusion in a pediatric patient with syrinx and previous Chiari decompression, which reversed with urgent rod removal.

CONCLUSION

There is limited literature on delayed cord injury occurring after surgery in a patient with scoliosis of neuromuscular origin. Patients with syrinx and a history of Chiari decompression may have spinal cords more sensitive to injury including delayed ischemia after deformity treatment and should be paid extra perioperative attention including considering prolonged mean arterial pressure goals or more conservative deformity correction.

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

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.

Chiari I malformations with syringomyelia: long-term results of neurosurgical decompression

STUDY DESIGN

Retrospective case series.

OBJECTIVES

The objective was to assess the long-term outcomes on scoliosis following Chiari-I (CM-I) decompression in patients with CM-I and syringomyelia (SM). A secondary objective was to identify risk factors of scoliosis progression.

BACKGROUND

The association between CM-I with SM and scoliosis is recognized, but it remains unclear if CM-I decompression alters the long-term evolution of scoliosis in patients with associated syringomyelia.

METHODS

A retrospective review of children with scoliosis, CM-I, and SM during 1997-2015 was performed. Congenital, syndromic, and neuromuscular scoliosis were excluded. Clinical and radiographic characteristics were recorded at presentation, pre-decompression, after 1-year, and latest follow-up. A scale to measure syringomyelia area on MRI was used to evaluate SM changes post-decompression.

RESULTS

65 children with CM-I, SM, and scoliosis and a mean age of 8.9 years (range 0.7-15.8) were identified. Mean follow-up was 6.9 years (range 2.0-20.4). Atypical curves were present in 28 (43%) children. Thirty-eight patients (58%) underwent decompression before 10 years. Syringomyelia size reduced a mean of 70% after decompression (p < 0.001). Scoliosis improved in 26 (40%), stabilized in 17 (26%), and progressed in 22 (34%) cases. Early spinal fusion was required in 7 (11%) patients after a mean of 0.5 ± 0.37 years and delayed fusion in 16 (25%) patients after 6.0 ± 3.24 years. The remaining 42 (65%) patients were followed for a median of 6.1 years (range 2.0-12.3) without spine instrumentation or fusion. Fusion patients experienced less improvement in curve magnitude 1-year post-decompression (p < 0.001) and had larger curves at presentation (43° vs. 34°; p = 0.004).

CONCLUSIONS

Syringomyelia size decreased by 70% after CM-I decompression and scoliosis stabilized or improved in two-thirds of patients. Greater curve improvement within the first year post-decompression and smaller curves at presentation decreased the risk of spinal fusion. Neurosurgical decompression is recommended in children with CM-I, SM, and scoliosis with the potential to treat all three conditions.

LEVEL OF EVIDENCE

Level IV.

Somatosensory and motor evoked potentials during correction surgery of scoliosis in neurologically asymptomatic Chiari malformation-associated scoliosis: A comparison with idiopathic scoliosis

OBJECTIVES

To analyze the somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) in neurologically asymptomatic Chiari malformation-associated scoliosis (CMS) patients with and without syringomyelia as compared with those in idiopathic scoliosis (IS) ones, and to identify whether the deformities have impacts on the neurophysiological monitoring.

PATIENTS AND METHODS

This study included neurologically asymptomatic CMS patients undergoing posterior correction surgery between January 2010 and January 2016. IS patients were involved as control group and a subgroup of age- and height-matched IS patients were selected. The age, standing height and Cobb angles of main curve were measured. The SEPs latency and amplitude, MEPs amplitude, and the rate of abnormal SEPs pathologic change were compared between CMS and IS patients using independent-sample t-test and Chi-square test.

RESULTS

Sixty CMS patients and 210 IS patients were included. There was no difference between CMS patients and IS or matched IS patients in SEPs latency and amplitude, MEPs amplitude or rate of abnormal SEPs (p > 0.05). Forty-eight CMS patients concurrent with syringomyelia were associated with higher Cobb angle of main curve and lower SEPs amplitude than those without syringomyelia (p < 0.05). No significant difference was found between CMS patients with and without syringomyelia in age, height, SEPs latency, MEPs amplitude or rate of abnormal SEPs (p > 0.05).

CONCLUSION

Neurologically asymptomatic CMS patients showed similar absolute values of neurophysiological monitoring with IS patients. The syringomyelia in CMS indicated more severe curvature and lower SEPs amplitude even after posterior fossa decompression.

Radiological and clinical predictors of scoliosis in patients with Chiari malformation type I and spinal cord syrinx from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors' goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis.

METHODS

A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°).

RESULTS

Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB-C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude.

CONCLUSIONS

Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.

Management of Chiari I malformations: a paradigm in evolution

PURPOSE

Despite decades of experience and research, the etiology and management of Chiari I malformations (CM-I) continue to raise more questions than answers. Controversy abounds in every aspect of management, including the indications, timing, and type of surgery, as well as clinical and radiographic outcomes. This review aims to outline past experiences, consolidate current evidence, and recommend directions for the future management of the Chiari I malformation.

METHODS

A review of recent literature on the management of CM-I in pediatric patients is presented, along with our experience in managing 1073 patients who were diagnosed with CM-I over the past two decades (1998-2018) at Children's National Medical Center (CNMC) in Washington DC.

RESULTS

The general trend reveals an increase in the diagnosis of CM-I at younger ages with a significant proportion of these being incidental findings (0.5-3.6%) in asymptomatic patients as well as a rise in the number of patients undergoing Chiari posterior fossa decompression surgery (PFD). The type of surgical intervention varies widely. At our institution, 104 (37%) Chiari surgeries were bone-only PFD with/without outer leaf durectomy, whereas 177 (63%) were PFD with duraplasty. We did not find a significant difference in outcomes between the PFD and PFDD groups (p = 0.59). An analysis of failures revealed a significant difference between patients who underwent tonsillar coagulation versus those whose tonsils were not manipulated (p = 0.02).

CONCLUSION

While the optimal surgical intervention continues to remain elusive, there is a shift away from intradural techniques in favor of a simple, extradural approach (including dural delamination) in pediatric patients due to high rates of clinical and radiographic success, along with a lower complication rate. The efficacy, safety, and necessity of tonsillar manipulation continue to be heavily contested, as evidence increasingly supports the efficacy and safety of less tonsillar manipulation, including our own experience.

Scoliosis in patients with Chiari malformation type I

The literature about the association between Chiari malformations (CMs) and scoliosis has been growing over the last three decades; yet, no consensus on the optimal management approach in this patient population has been reached. Spinal anomalies such as isolated syrinxes, isolated CM, and CM with a syrinx are relatively common among patients with presumed idiopathic scoliosis (IS), a rule that also applies to scoliosis among CM patients as well. In CM patients, scoliosis presents with atypical features such as early onset, left apical or kyphotic curvature, and neurological deficits. While spinal X-rays are essential to confirm the diagnosis of scoliosis among CM patients, a magnetic resonance imaging (MRI) is also recommended in IS patients with atypical presentations. Hypotheses attempting to explain the occurrence of scoliosis in CM patients include cerebellar tonsillar compression of the cervicomedullary junction and uneven expansion of a syrinx in the horizontal plane of the spinal cord. Early detection of scoliosis on routine spinal examination and close follow-up on curve stability and progression are essential initial steps in the management of scoliosis, especially in patients with CM, who may require full spine MRI to screen for associated neuro-axial anomalies; bracing and spinal fusion may be subsequently pursued in high-risk patients.

Chiari-related scoliosis: a single-center experience with long-term radiographic follow-up and relationship to deformity correction

OBJECTIVE Previous reports have addressed the short-term response of patients with Chiari-related scoliosis (CRS) to suboccipital decompression and duraplasty (SODD); however, the long-term behavior of the curve has not been well defined. The authors undertook a longitudinal study of a cohort of patients who underwent SODD for CRS to determine whether there are factors related to Chiari malformation (CM) that predict long-term scoliotic curve behavior and need for deformity correction. METHODS The authors retrospectively reviewed cases in which patients underwent SODD for CRS during a 14-year period at a single center. Clinical (age, sex, and associated disorders/syndromes) and radiographic (CM type, tonsillar descent, pBC2 line, clival-axial angle [CXA], syrinx length and level, and initial Cobb angle) information was evaluated to identify associations with the primary outcome: delayed thoracolumbar fusion for progressive scoliosis. RESULTS Twenty-eight patients were identified, but 4 were lost to follow-up and 1 underwent fusion within a year. Among the remaining 23 patients, 11 required fusion surgery at an average of 88.3 ± 15.4 months after SODD, including 7 (30%) who needed fusion more than 5 years after SODD. On univariate analysis, a lower CXA (131.5° ± 4.8° vs 146.5° ± 4.6°, p = 0.034), pBC2 > 9 mm (64% vs 25%, p = 0.06), and higher initial Cobb angle (35.1° ± 3.6° vs 22.8° ± 4.0°, p = 0.035) were associated with the need for thoracolumbar fusion. Multivariable modeling revealed that lower CXA was independently associated with a need for delayed thoracolumbar fusion (OR 1.12, p = 0.0128). CONCLUSIONS This investigation demonstrates the long-term outcome and natural history of CRS after SODD. The durability of the effect of SODD on CRS and curve behavior is poor, with late curve progression occurring in 30% of patients. Factors associated with CRS progression include an initial pBC2 > 9 mm, lower CXA, and higher Cobb angle. Lower CXA was an independent predictor of delayed thoracolumbar fusion. Further study is necessary on a larger cohort of patients to fully elucidate this relationship.

Factors associated with spinal fusion after posterior fossa decompression in pediatric patients with Chiari I malformation and scoliosis

OBJECTIVE The authors performed a study to identify clinical characteristics of pediatric patients diagnosed with Chiari I malformation and scoliosis associated with a need for spinal fusion after posterior fossa decompression when managing the scoliotic curve. METHODS The authors conducted a multicenter retrospective review of 44 patients, aged 18 years or younger, diagnosed with Chiari I malformation and scoliosis who underwent posterior fossa decompression from 2000 to 2010. The outcome of interest was the need for spinal fusion after decompression. RESULTS Overall, 18 patients (40%) underwent posterior fossa decompression alone, and 26 patients (60%) required a spinal fusion after the decompression. The mean Cobb angle at presentation and the proportion of patients with curves > 35° differed between the decompression-only and fusion cohorts (30.7° ± 11.8° vs 52.1° ± 26.3°, p = 0.002; 5 of 18 vs 17 of 26, p = 0.031). An odds ratio of 1.0625 favoring a need for fusion was established for each 1° of increase in Cobb angle (p = 0.012, OR 1.0625, 95% CI 1.0135-1.1138). Among the 14 patients older than 10 years of age with a primary Cobb angle exceeding 35°, 13 (93%) ultimately required fusion. Patients with at least 1 year of follow-up whose curves progressed more 10° after decompression were younger than those without curve progression (6.1 ± 3.0 years vs 13.7 ± 3.2 years, p = 0.001, Mann-Whitney U-test). Left apical thoracic curves constituted a higher proportion of curves in the decompression-only group (8 of 16 vs 1 of 21, p = 0.002). CONCLUSIONS The need for fusion after posterior fossa decompression reflected the curve severity at clinical presentation. Patients presenting with curves measuring > 35°, as well as those greater than 10 years of age, may be at greater risk for requiring fusion after posterior fossa decompression, while patients less than 10 years of age may require routine monitoring for curve progression. Left apical thoracic curves may have a better response to Chiari malformation decompression.

Comparison of clinical and radiological manifestations and surgical outcomes of pediatric Chiari I malformations in different age groups

PURPOSE

The aim of this study was to elucidate the differences in clinical and radiological manifestations and treatment outcomes of pediatric Chiari I malformation patients according to age.

METHODS

We retrospectively reviewed the patients who received surgery in our institution for symptomatic Chiari I malformations between January 1991 and December 2012. Fifty-four patients were identified, and their medical records were reviewed for clinical presentation, radiological findings, surgical treatment, and outcomes including complications. We divided the patients into 3 groups: Group I (n = 4) younger than 3 years old; Group II (n = 9) between 3 and 5 years old; and Group III (n = 41) older than 5 years old. Surveyed data were compared among the groups. The mean follow-up period was 82.8 months.

RESULTS

All of Group I patients presented with stem compression signs. Ventriculomegaly was common (3/4, 75%), but no syrinx or scoliosis was observed. In Group II, scoliosis was the most common presentation (5/9, 56%), and these patients rarely complained any other symptoms. Pain, such as headache (18/41, 44%), was the predominant presentation in Group III. The incidences of syrinx and scoliosis were similar in Groups II and III. There were no differences in the treatment outcomes among the groups. The spinal curve did not improve in 4 of 5 Group II patients despite their early FMD surgeries. The incidence of complications related to cerebrospinal fluid leakage was higher in the young age group.

CONCLUSIONS

The clinical and radiological manifestations of pediatric Chiari I malformation appeared to be different according to age.

Management of idiopathic pediatric syringohydromyelia

OBJECT

Syringohydromyelia is frequently identified on spinal imaging. The literature provides little guidance to decision making regarding the need for follow-up or treatment. The purpose of this study was to review the authors' experience in managing pediatric syringohydromyelia of unknown cause.

METHODS

A single-institution retrospective review of all cases involving pediatric patients who underwent spinal MRI from 2002 to 2012 was conducted. Patients with idiopathic syringohydromyelia (IS) were identified and categorized into 2 subgroups: uncomplicated idiopathic syrinx and IS associated with scoliosis. Clinical and radiological course were analyzed.

RESULTS

Ninety-eight patients (50 female, 48 male) met the inclusion criteria. Median age at diagnosis of syrinx was 11.9 years. Median maximum syrinx size was 2 mm (range 0.5-17 mm) and spanned 5 vertebral levels (range 1-20 vertebral levels). Thirty-seven patients had scoliosis. The most common presenting complaint was back pain (26%). Clinical follow-up was available for 78 patients (80%), with a median follow-up of 20.5 months (range 1-143 months). A neurological deficit existed at presentation in 36% of the patients; this was either stable or improved at last follow-up in 64% of cases. Radiological follow-up was available for 38 patients (39%), with a median duration of 13 months (range 2-83 months). There was no change in syrinx size in 76% of patients, while 16% had a decrease and 8% had an increase in syrinx size. Thirty-six patients had both clinical and radiological follow-up. There was concordance between clinical and radiological course in 14 patients (39%), with 11 patients (31%) showing no change and 3 patients (8%) showing clinical and radiological improvement. No patients had concurrent deterioration in clinical and radiological course. One patient with scoliosis and muscular dystrophy underwent direct surgical treatment of the syrinx and subsequently had a deteriorated clinical course and decreased syrinx size.

CONCLUSIONS

There remains a paucity of data regarding the management of pediatric IS. IS in association with scoliosis can complicate neurosurgical decision making. There was no concordance between radiological syrinx size increase and clinical deterioration in this cohort, indicating that surgical decision making should reflect clinical course as opposed to radiological course.

Risks and outcomes of spinal deformity surgery in Chiari malformation, Type 1, with syringomyelia versus adolescent idiopathic scoliosis

BACKGROUND CONTEXT

Chiari malformation, Type 1, with syringomyelia (CIM+SM) is often associated with spinal deformity. The safety of scoliosis surgery this population is controversial and has never been directly compared with adolescent idiopathic scoliosis (AIS).

PURPOSE

The purpose of this study was to compare the safety and subjective outcomes of spinal deformity surgery between patients with Chiari malformation Type 1-associated scoliosis and a matched AIS cohort.

STUDY DESIGN

This study is based on a retrospective matched cohort analysis.

PATIENT SAMPLE

Patients with CIM+SM and treated with spinal fusion for spinal deformity were identified in the surgical records of a single institution and were matched, 1:1, with AIS patients undergoing spinal fusion at the same institution.

OUTCOME MEASURES

The outcome measures were neurological monitoring data quality and integrity, radiographic parameters, and Scoliosis Research Society Questionnaire-22 (SRS-22) scores.

METHODS

A clinical database was reviewed for patients undergoing spinal reconstruction for CIM+SM-associated spinal deformity at our institution from 2000 to 2012. Thirty-six CIM+SM patients were identified and matched to an AIS cohort (1:1) based on age, gender, major curve magnitude, fusion length, and revision status. Demographics, deformity morphology, surgical details, neuromonitoring data, and preoperative and postoperative SRS-22 scores were recorded at a minimum of 2-year follow-up. Changes in SRS-22 scores were compared within and between groups. Complications and neurological monitoring data issues were compared between groups.

RESULTS

Mean age was 14.5±5 years (CIM+SM: 14.6±5; AIS: 14.4±5), and 42% of patients were male. Preoperative mean major coronal Cobb measured 58°±25° versus 57°±17° (p=.84) with mean kyphosis 52°±17° versus 41°±20° (p=.018). An average of 10.4±2.6 vertebral levels were fused (10.4±2.8 vs. 10.4±2.3, p=.928). No differences existed in surgical approach (p=.336), estimated blood loss (680±720 vs. 660±310 mL, p=.845), or duration of surgery (6.0±2.2 vs. 5.6±2 hours, p=.434). Complication rate was comparable between the two groups (33% vs. 14%, p=.052). Chiari malformation, Type 1, with syringomyelia experienced more neurological complications (11% vs. 0%, p=.04) and neuromonitoring difficulties (28% vs. 3%, p=.007) than the AIS cohort. Mean curve correction was comparable at 2 years (58% CIM+SM vs. 64% AIS, p=.2). At follow-up, both CIM+SM and AIS groups demonstrated improved cumulative SRS-22 outcome subscores (CIM+SM: +0.4, p=.027; AIS: +0.3, p<.001). No difference in outcome subscores existed between CIM+SM and AIS groups.

CONCLUSIONS

Although CIM+SM patients undergoing spine reconstruction can expect similar deformity corrections and outcome scores to AIS patients, they also experience higher rates of neuromonitoring difficulties and neurological complications related to surgery. Surgeons should be prepared for these difficulties, particularly in children with larger syrinx size.

Relationship of syrinx size and tonsillar descent to spinal deformity in Chiari malformation Type I with associated syringomyelia

OBJECT

Chiari malformation Type I (CM-I) is a developmental abnormality often associated with a spinal syrinx. Patients with syringomyelia are known to have an increased risk of scoliosis, yet the influence of specific radiographically demonstrated features on the prevalence of scoliosis remains unclear. The primary objective of the present study was to investigate the relationship of maximum syrinx diameter and tonsillar descent to the presence of scoliosis in patients with CM-I-associated syringomyelia. A secondary objective was to explore the role of craniovertebral junction (CVJ) characteristics as additional risk factors for scoliosis.

METHODS

The authors conducted a retrospective review of pediatric patients evaluated for CM-I with syringomyelia at a single institution in the period from 2000 to 2012. Syrinx morphology and CVJ parameters were evaluated with MRI, whereas the presence of scoliosis was determined using standard radiographic criteria. Multiple logistic regression was used to analyze radiological features that were independently associated with scoliosis.

RESULTS

Ninety-two patients with CM-I and syringomyelia were identified. The mean age was 10.5 ± 5 years. Thirty-five (38%) of 92 patients had spine deformity; 23 (66%) of these 35 patients were referred primarily for deformity, and 12 (34%) were diagnosed with deformity during workup for other symptoms. Multiple regression analysis revealed maximum syrinx diameter > 6 mm (OR 12.1, 95% CI 3.63-40.57, p < 0.001) and moderate (5-12 mm) rather than severe (> 12 mm) tonsillar herniation (OR 7.64, 95% CI 2.3-25.31, p = 0.001) as significant predictors of spine deformity when controlling for age, sex, and syrinx location.

CONCLUSIONS

The current study further elucidates the association between CM-I and spinal deformity by defining specific radiographic characteristics associated with the presence of scoliosis. Specifically, patients presenting with larger maximum syrinx diameters (> 6 mm) have an increased risk of scoliosis.

Brace treatment versus observation alone for scoliosis associated with Chiari I malformation following posterior fossa decompression: a cohort study of 54 patients

PURPOSE

To be deemed effective in preventing curve progression, brace treatment should show alteration of the expected natural history. Most of the reported studies on the effect of bracing on the evolution of Chiari malformation-associated scoliosis (CMS) following posterior fossa decompression (PFD) were small series with inconclusive results. The goal of this study was to investigate whether post-PFD brace treatment for CMS produces better outcomes than observation alone.

METHODS

The clinical and radiographic data of 21 patients treated with observation alone (Ob group) and 33 patients receiving brace treatment (Br group) were retrospectively reviewed. Evolution of scoliosis was defined as progression of Cobb angle of the primary curve of >5°, as compared with that at brace initiation.

RESULTS

At the latest follow-up, curve progression occurred in 10 (30 %) of Br group and 13 (62 %) of Ob group (P = .022). Overall, 8 (24 %) patients in the Br group and 9 (43 %) in the Ob group underwent further scoliosis surgery (P = .151). When analyses were restricted to the 27 braced and 17 observed patients who had reached skeletal maturity or undergone spinal fusion surgery, decreased curve progression and surgical rates were also observed in the Br group though not reaching statistical significance. Results of the survival analysis, however, demonstrated a significantly increased survival proportion in the Br group (0.63 versus 0.35, P = .014).

CONCLUSIONS

Compared with observation alone, bracing treatment following PFD in patients with CMS was observed to reduce the rates of curve progression and scoliosis surgery. However, patients and their parents should be informed that almost a third of patients still go on to surgery.

Scoliosis-Associated Cervical Spine Pathologies

STUDY DESIGN

A total of 126 scoliosis patients admitted to the hospital were screened for concomitant cervical pathologies.

OBJECTIVES

To investigate the prevalence of cervical spine pathologies and the clinical relevance of magnetic resonance imaging (MRI) in the evaluation of patients with neuromuscular, congenital, syndromic, and idiopathic scoliosis.

BACKGROUND SUMMARY

With the development of MRI, upper neural axis abnormalities such as syringomyelia and Chiari malformation are increasingly being found in patients with scoliosis, but no report in the literature describes other pathologies in the cervical area seen concomitant with different scoliosis types.

METHODS

A total of 126 consecutive patients who were classified as having neuromuscular, congenital, syndromic, and idiopathic scoliosis were retrospectively evaluated. Data regarding cervical neural axis abnormalities obtained from the MRI studies were analyzed and classified into each type of scoliosis group.

RESULTS

A total of 126 patients with scoliosis were evaluated for hindbrain and cervical spine anomalies. Patients were divided into 4 groups regarding the type of scoliosis. The cervical spine of all patients was evaluated with MRI and other radiologic methods when needed. The most frequently seen pathology was syringomyelia. Other pathologies found included congenital vertebral anomalies, Chiari malformation, arachnoid cyst, atlanto-axial dissociation, split cord, posterior vertebral fusion, vertebral hypoplasia, neurenteric cyst, myelomalacia, dermoid cyst, and decrease in craniovertebral angle. Cervical pathologies were most frequently seen in neuromuscular scoliosis, followed by congenital and syndromic groups.

CONCLUSIONS

Cervical spinal pathologies vary according to the type of scoliosis. The number of cervical spinal pathologies diagnosed in idiopathic scoliosis patients was least compared with neuromuscular and syndromic groups. The most common pathology was syringomyelia, followed by congenital vertebral anomalies and cerebral tonsillar hernia. Preoperative MRI scan provides vital information regarding cervical spinal pathologies encountered in scoliosis patients.

[Scoliotic spine deformity in children and adolescents associated with the craniovertebral junction pathology]

This literature review is devoted to the clinical and pathogenic aspects of the relationship between Chiari type I malformation (CMT) and scoliosis. The view of the clinical presentation development in CMT associated with scoliosis is considered on the basis of both the CSF dynamics disturbances and vascular pathology of the craniovertebral junction. The role of the posterior atlanto-occipital membrane is evaluated. Case reports of the risk factors for scoliosis progression in patients with CMT are presented.

Syringomyelia and tethered cord in children

INTRODUCTION

The presence of syringomyelia varies in patients with different forms of dysraphism; from 21 % to 67 %. Only around 60 % of patients with syringomyelia is likely to experience symptoms related to it.

PATHOPHYSIOLOGY

Many theories have been outlined for the creation of syringomyelia. The one most applicable to tethered cord dictates that tensile radial stress may create a syrinx in a previously normal cord tissue and transiently lower pressure may draw in interstitial fluid, causing the syrinx to enlarge if fluid exit is inhibited. In addition, arachnoiditis increases flow resistance in the spinal subarachnoid space, altering temporal CSF pulse pressure dynamics, which promotes entry of CSF in to the spinal cord.

CLINICAL PRESENTATION

There is a significant overlap between the symptoms that are due to tethered cord and syringomyelia, both in newly presenting patients with coexisting syringomyelia, and in previously treated patients who during follow-up present recurrent symptoms and a new syringomyelia cavity.

TREATMENT

The treatment of patients with tethered cord and syringomyelia is directed towards untethering the cord from its most caudal region upwards and restoring spinal anatomy with reestablishment of unobstructed CSF flow in the subarachnoid space. Only if complete untethering has been ensured and syringomyelia deteriorates, then surgical treatment can be directed against the syrinx. In patients with spinal dysraphism and coexisting hydrocephalus, radiological presentation of new syringomyelia or deterioration of previously known syringomyelia may signify shunt obstruction "until proven otherwise".

CONCLUSION

In most occasions, satisfactory cord untethering addresses the development of syringomyelia.

Effectiveness of brace treatment of Chiari malformation-associated scoliosis after posterior fossa decompression: a comparison with idiopathic scoliosis

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

To evaluate the effectiveness of bracing in patients with Chiari malformation-associated scoliosis (CMS) after posterior fossa decompression (PFD).

SUMMARY OF BACKGROUND DATA

The effectiveness of bracing has been poorly studied in patients with CMS who have undergone PFD.

METHODS

A retrospective study was conducted on 22 patients with CMS who received brace treatment of scoliosis after PFD. Forty-four age- and sex-matched patients with idiopathic scoliosis (IS) who were treated with bracing served as the control group. The bracing outcome was considered a failure if the curve worsened 6° or more; otherwise, the treatment was considered to be successful.

RESULTS

The age and Risser sign were similar between patients with CMS and IS at brace initiation. The initial curve magnitude of patients with CMS (mean, 32.9° ± 6.3°; range, 20°-45°) was marginally significantly larger than that of patients with IS (mean, 29.6° ± 6.4°; range, 20°-45°). Until the final follow-up, a 6° or more worsening of the major curve occurred in 8 patients with CMS (36%) and in 15 patients with IS (34%). Overall, 7 patients with CMS (32%) and 13 patients with IS (30%) underwent spinal fusion surgery. No significant differences were observed between the 2 groups in the surgery rates or the bracing success rates (P > 0.05). In patients with CMS, neither the performance of syringosubarachnoid shunting nor the extent of tonsillar descent correlated with the bracing outcomes, whereas a double major curve pattern was found to be predictive for the failure of bracing.

CONCLUSION

Brace treatment subsequent to PFD is effective in preventing curve progression for 64% of patients with CMS, which is comparable with the rate that is observed in patients with IS. Double major curve pattern may be a risk factor in predicting treatment failure in patients with CMS.

LEVEL OF EVIDENCE

3.

Prediction of Curve Progression After Posterior Fossa Decompression in Pediatric Patients With Scoliosis Secondary to Chiari Malformation

OBJECTIVE

In this retrospective radiographic and clinical study, we analyzed the evolution of scoliosis after posterior fossa decompression (PFD) to determine the predictors of curve progression after PFD in patients with scoliosis secondary to Chiari malformation type I (CM-I) and syringomyelia (SM). Institutional Review Board approval was obtained to conduct the study. Previous studies have shown that PFD can improve the associated scoliosis in some patients with CM-I, and certain clinical factors can predict curve progression after PFD. However, the results were often contradictory.

METHODS

In our study, 54 patients with CM-I who underwent a standard PFD were divided into 2 groups according to the evolution of scoliosis after PFD. One group consisted of "progressors" with curve progression of more than 5° from before PFD to the final follow-up; the other group consisted of "nonprogressors" with curve stabilization or improvement. Clinical and radiographic data were compared between progressors and nonprogressors.

RESULTS

Twenty-five of the patients received brace treatment, and 11 patients underwent spinal fusion. Nineteen patients were identified as progressors, and 35 were nonprogressors. Age, curve type, curve magnitude, and bracing treatment were independent predictors for curve progression after PFD. Both an age ≥ 10.5 years and a Cobb angle ≥ 44.5° were strongly predictive factors for curve progression. Regarding those patients with an indication for bracing, a significant difference (p=.009) was noted in terms of the evolution of scoliosis between patients with and without bracing treatment.

CONCLUSION

PFD had an effect on the regression of scoliosis in 64.8% of the CM-I patients. An age ≥ 10.5 years, a Cobb angle ≥ 44.5°, and double curves were factors that could predict the progression of scoliosis in these patients. Additionally, we advocate that bracing treatment may be effective in some skeletally immature patients.

Outcomes of Chiari I-associated scoliosis after intervention: a meta-analysis of the pediatric literature

PURPOSE

Various series have reported successful management of scoliosis after surgical treatment of the associated Chiari malformation, syrinx, or bracing. Multiple factors have been associated with curve progression, but interpretation of outcomes is confounded by the wide range of reported results and size of individual series. We attempted to evaluate the outcomes of Chiari I-associated scoliosis by performing a meta-analysis of currently published data.

METHODS

We conducted a systematic review of published articles using Medline, PubMed (from 1950 to January 2010), and reference lists of identified articles for Chiari malformation and scoliosis.

RESULTS

One hundred and twenty patients were identified in 12 studies, of them, 37 % were male. The mean age at the time of surgery was 9.7 ± 4.1 years. The mean curve magnitude at presentation was 34.4 ± 13.0° and progressed to a mean value of 38.9 ± 20.2°, with an average follow-up of 48.3 ± 48.2 months. After surgical intervention, curve magnitude improved in 37 % of patients (n = 42); there was no change in 18 % (n = 20), and curves progressed in 45 % (n = 51). Age (p = 0.0097) and presence of surgical intervention (foramen magnum decompression [p = 0.0099] and syrinx shunting/drainage [p = 0.0039]) were statistically associated with improvement of the scoliotic curve. Surgical decompression of the foramen magnum had the greatest impact on the scoliotic curves.

CONCLUSIONS

Data accrued from our analysis suggest that curve magnitude will improve after surgical treatment of the Chiari malformation in one third of patients, and curve progression will stabilize or improve in one half.

Chiari malformation: are children little adults?

OBJECTIVES

To discuss the controversies, variability of opinion and approach, and special considerations in pediatric Chiari malformation.

METHODS

PubMed-based literature review with focused discussion on clinically relevant pediatric issues.

RESULTS

Compared to adults, children with Chiari more often present with congenital anomalies, scoliosis, and deficits in oropharyngeal control. Those with a syrinx present more with scoliosis than with deficits in sensation or pain. Surgical intervention has varied widely in its level of invasiveness though there has been a trend towards less invasive procedures with bony decompression only, especially in children where their dura may be more flexible and minimal procedures may lead to fewer complications and faster recovery.

CONCLUSIONS

Pediatric Chiari management must consider the effect of development, increased activity, and a longer life course on the decision to surgically treat. However, little is known about predicting the natural history of Chiari in the young. There is also difference in opinion regarding activity restriction since the number of asymptomatic children with Chiari is not known. The long-term effectiveness of less invasive procedures remains to be determined.

One-stage and posterior approach for correction of moderate to severe scoliosis in adolescents associated with Chiari I malformation: is a prior suboccipital decompression always necessary?

Priority of neurological decompression was regarded as necessary for scoliosis patients associated with Chiari I malformation in order to decrease the risk of spinal cord injury from scoliosis surgery. We report a retrospective series of scoliosis associated with Chiari I malformation in 13 adolescent patients and explore the effectiveness and safety of posterior scoliosis correction without suboccipital decompression. One-stage posterior approach total vertebral column resection was performed in seven patients with scoliosis or kyphosis curve >90° (average 100.1° scoliotic and 97.1° kyphotic curves) or presented with apparent neurological deficits, whereas the other six patients underwent posterior pedicle screw instrumentation for correction of spinal deformity alone (average 77.3° scoliotic and 44.0° kyphotic curves). The apex of the scoliosis curve was located at T7-T12. Mean operating time and intraoperative hemorrhage was 463 min and 5,190 ml in patients undergoing total vertebral column resection, with average correction rate of scoliosis and kyphosis being 63.3 and 71.1%, respectively. Mean operating time and intraoperative hemorrhage in patients undergoing instrumentation alone was 246 min and 1,450 ml, with the average correction rate of scoliosis and kyphosis being 60.8 and 53.4%, respectively. The mean follow-up duration was 32.2 months. No iatrogenic neurological deterioration had been encountered during the operation procedure and follow-up. After vertebral column resection, neurological dysfunctions such as relaxation of anal sphincter or hypermyotonia that occurred in three patients preoperatively improved gradually. In summary, suboccipital decompression prior to correction of spine deformity may not always be necessary for adolescent patients with scoliosis associated with Chiari I malformation. Particularly in patients with a severe and rigid curve or with significant neurological deficits, posterior approach total vertebral column resection is likely a good option, which could not only result in satisfactory correction of deformity, but also decrease the risk of neurological injury secondary to surgical intervention by shortening spine and reducing the tension of spinal cord.

The utility of superficial abdominal reflex in the initial diagnosis of scoliosis: a retrospective review of clinical characteristics of scoliosis with syringomyelia

Background

With increasing use of magnetic resonance imaging (MRI), underlying syringomyelia is increasingly found in patients with presumed idiopathic scoliosis. To determine the indications for MRI in the differential diagnosis of scoliosis, several clinical characteristics of syringomyelia have been reported. Neurological signs, particularly abnormal superficial abdominal reflex (SAR), are important in establishing the initial diagnosis of scoliosis. However, the prevalence of abnormal SAR in patients with scoliosis and the sensitivity of this sign in predicting syringomyelia are not well known. We aimed to determine the diagnostic utility of SAR and other characteristics of syringomyelia in patients with scoliosis.

Methods

We reviewed the medical records of 93 patients with scoliosis, 90 of whom underwent corrective surgery. All patients underwent MRI to determine the presence of syringomyelia. Mean age at surgery was 12.5 years. Abnormal SAR was defined as unilateral or bilateral absence or hyporeflexia of SAR. We calculated indices of diagnostic utility of abnormal SAR for non-idiopathic scoliosis and for syringomyelia. Abnormal SAR, left thoracic curve pattern, gender, and curve flexibility were compared between scoliosis with syringomyelia and idiopathic scoliosis. Logistic regression analysis was performed with the existence of syringomyelia as the dependent variable and curve flexibility as the independent variable.

Results

Abnormal SAR was observed in 20 patients (prevalence 22%). All 6 patients with myopathic scoliosis displayed bilateral absence of SAR. The sensitivity of abnormal SAR for non-idiopathic scoliosis was 38%, with 96% specificity, 90% PPV (positive predictive value), and 60% NPV (negative predictive value). Syringomyelia was identified in 9 of the 93 patients (9.7%); 8 of these had abnormal SAR. The sensitivity of abnormal SAR for syringomyelia in presumed idiopathic scoliosis was 89%, with 95% specificity, 80% PPV, and 98% NPV. Gender, abnormal neurological findings, and curve flexibility differed significantly between patients with syringomyelia and those with idiopathic scoliosis (P < 0.05). In the logistic regression model, the area under the receiver operating characteristic (ROC) curve was 0.79 and the cut-off value of curve flexibility for syringomyelia was 50% (P = 0.08).

Conclusion

Abnormal SAR was a useful indicator not only for syringomyelia, but also for myogenic scoliosis.

Pathogenesis of syringomyelia associated with Chiari type 1 malformation: review of evidences and proposal of a new hypothesis

The exact pathogenesis of syringomyelia associated with Chiari type 1 malformation is unknown, although a number of authors have reported their theories of syrinx formation. The purpose of this review is to understand evidences based on the known theories and to create a new hypothesis of the pathogenesis. We critically review the literatures on clinicopathological, radiological, and clinical features of this disorder. The previously proposed theories mainly focused on the driven mechanisms of the cerebrospinal fluid (CSF) into the spinal cord. They did not fully explain radiological features or effects of surgical treatment such as shunting procedures. Common findings of the syrinx in clinicopathological studies were the communication with the central canal and extracanalicular extension to the posterior gray matter. Most of the magnetic resonance imaging studies demonstrated blockade and alternated CSF dynamics at the foramen magnum, but failed to show direct communication of the syrinx with the CSF spaces. Pressure studies revealed almost identical intrasyrinx pressure to the subarachnoid space and decreased compliance of the spinal CSF space. Recent imaging studies suggest that the extracellular fluid accumulation may play an important role. The review of evidences promotes a new hypothesis of syrinx formation. Decreased absorption mechanisms of the extracellular fluid may underlie the pathogenesis of syringomyelia. Reduced compliance of the posterior spinal veins associated with the decreased compliance of the spinal subarachnoid space will result in disturbed absorption of the extracellular fluid through the intramedullary venous channels and formation of syringomyelia.

Chiari malformation Type I in children younger than age 6 years: presentation and surgical outcome

OBJECT

The authors conducted a study to evaluate the unique presenting signs and symptoms of Chiari malformation Type I (CM-I) in children younger than 6 years of age and highlight the benefits of early surgical treatment in this patient population.

METHODS

The authors reviewed the medical records of patients who presented to the neurosurgery department before their 6th birthday and subsequently underwent surgery for CM-I. They identified 39 patients who had been evaluated between 1984 and 2007 and examined the medical records for presentation, surgical intervention, and outcome.

RESULTS

Children aged 0-2 years commonly presented with oropharyngeal dysfunction (77.8%). Children aged 3-5 years more frequently presented with syringomyelia (85.7%), scoliosis (38.1%), and/or headache (57.1%). All patients underwent posterior fossa craniectomy. Additionally, in many patients cervical laminectomy and/or duraplasty was performed. A few patients required transoral decompression and occipitocervical fusion. In most cases, surgery led to resolution or dramatic improvement of initial symptoms.

CONCLUSIONS

Early recognition and surgical treatment of CM-I in young children leads to good outcomes in the majority of patients. Additional therapies for oropharyngeal dysfunction, syringomyelia, and scoliosis can frequently be avoided.

Tonsillar ectopia in idiopathic scoliosis: does it play a role in the pathogenesis and prognosis or is it only an incidental finding?

Background

There is an ongoing controversy about the significance of tonsillar ectopia among patients with idiopathic scoliosis (IS).

Aim

To find out if tonsillar ectopia occurs more frequently among patients with IS and if it plays any etiological or prognostic role in IS.

Study design

Retrospective study.

Methods

Retrospective analysis of 155 consecutive spine MRIs (79 patients with IS and 76 controls; aged 7-25 years; 55% were female) with regard to the position of the cerebellar tonsils in relation to foramen magnum and the sagittal diameter of foramen magnum. All images were evaluated independently by two neuroradiologists. Interobserver and intraobserver reliability analysis was performed by calculation of κ-value, intraclass correlation coefficient, and systematic and random errors. The occurrence of tonsillar ectopia among patients with IS and controls was estimated and the association of tonsillar ectopia with different predictors has been tested. Statistical significance was set to P ≤ 0.05.

Results

The interobserver and intraobserver agreement with regard to the occurrence of tonsillar ectopia was almost perfect (κ 0.84 and 0.89, respectively). Tonsillar ectopia was found in 37% of patients with IS compared with 13% among controls (p < 0.001 and odds ratio of 3.8, 95% CI 1.7-8.5). The occurrence of tonsillar ectopia was not associated with the severity of scoliotic deformity (p = 0.85), or rapid progression of scoliosis (p = 0.76). Neurological deficit occurs twice as frequently in patients with tonsillar ectopia as in those with no tonsillar ectopia. Two of five patients with tonsillar ectopia showed improvement of their neurological deficit after the surgical correction of scoliosis.

Conclusion

As tonsillar ectopia is significantly more frequent among patients with IS and may exhibit some prognostic utility in patients with neurological deficit, we forward the hypothesis that tonsillar ectopia may play a role in the development of the deformity in some patients with IS. However, occurrence of tonsillar ectopia among 13% of controls precludes stating a definitive role of tonsillar ectopia in the pathogenesis of IS. Some patients with IS, tonsillar ectopia and neurological deficit showed neurological improvement following the surgical correction of scoliosis.

MRI Findings in Spinal MRI of 306 Children with Scoliosis

The aim of this study was to analyze the MRI findings and assess the prevalence of different associated structural abnormalities in children with scoliosis and to determine if the age of onset is a possible indicator of intraspinal pathology. This is a retrospective analysis of 663 consecutive MR examinations (319 patients). Thirteen patients with known intraspinal tumors were excluded and a total of 306 patients aged 2–18 years with scoliosis were subjected for analysis. The scoliosis was regarded as idiopathic in 62% of patients. Among the remaining 38% the most commonly seen abnormality was syrinx and Chiari malformations. There was no statistically significant difference in the occurrence of syrinx only or syrinx associated with Chiari I malformation in patients younger than ten years and those older than ten years. MRI examination is an essential part of the work up of scoliosis in the pediatric population especially before any corrective surgery. This study and a review of the current literature suggest there is no clinical marker that would definitely serve as an indicator of the presence of intraspinal pathology in these patients.

Suboccipital decompression for Chiari malformation-associated scoliosis: risk factors and time course of deformity progression

OBJECT

Chiari malformation Type I (CM-I) is often associated with scoliosis. It remains unclear which subgroups of patients are most likely to experience progression of spinal deformity after cervicomedullary decompression. The authors' goal was to determine the time frame of curvature progression and assess which patient subgroups are at greatest risk for progression of spinal deformity after surgery.

METHODS

The authors retrospectively reviewed the records of all pediatric patients with significant scoliosis in whom suboccipital decompression was performed to treat for CM-I during a 10-year period at a single academic institution. Clinical, radiological, and operative variables were assessed as independent factors for failure (worsening of scoliosis) by using a univariate regression analysis.

RESULTS

Twenty-one children (mean age 9 +/- 3 years; 4 male) underwent hindbrain decompression for CM-I-associated scoliosis and were followed for a mean of 39 months. All patients harbored a syrinx. Eight patients (38%) experienced improvement in scoliosis curvature, whereas 10 (48%) suffered a progression. Thoracolumbar junction scoliosis (p = 0.04) and failure of the syrinx to improve (p = 0.05) were associated with 5- and 4-fold respective increases in the likelihood of deformity progression. Each increasing degree of preoperative Cobb angle was associated with an 11% increase in the likelihood of scoliotic curve progression (p < 0.05).

CONCLUSIONS

Over one third of patients with CM-I-associated scoliosis will improve after cervicomedullary decompression alone. Cervicomedullary decompression is a good first-line option, particularly in children with concordant posterior fossa symptoms. Patients presenting with more severe scoliosis (increasing Cobb angle) or scoliosis that crosses the thoracolumbar junction may benefit from earlier orthopedic involvement and should be monitored regularly for curvature progression after cervicomedullary decompression. In cases in which there is a failure of the syrinx to show improvement after suboccipital decompression, the patients are also more likely to develop curvature progression.

The pediatric Chiari I malformation: a review

BACKGROUND

Both the diagnosis and treatment regimens for the Chiari I malformation (CIM) are varied and controversial. The present paper analyzes the literature regarding this form of hindbrain herniation in regard to definition, anatomy, pathobiology, symptoms, findings, treatment, and outcomes.

DISCUSSIONS

Appropriate literature germane to the CIM is reviewed and discussed. There is variation in the reported anatomy, outcome, and treatment for children with CIM. Based on the literature, most patients have preoperative symptoms or findings (e.g., syringomyelia) improve no matter what surgical technique is utilized. However, standardized treatment paradigms based on randomized controlled studies are still necessary to elucidate the optimal selection and treatment criteria.