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

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Study design

Retrospective case series.


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.


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.


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.


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).


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.

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All authors: substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work, drafting the work, or revising it critically for important intellectual content and final approval of the version to be published.

Correspondence to Michael P. Glotzbecker.

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Investigation performed at: Department of Orthopaedic Surgery, Boston Children’s Hospital (Harvard Teaching Hospital), Boston, MA, USA

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Verhofste, B.P., Davis, E.A., Miller, P.E. et al. Chiari I malformations with syringomyelia: long-term results of neurosurgical decompression. Spine Deform (2020) doi:10.1007/s43390-019-00009-z

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  • Chiari I
  • Syringomyelia
  • Decompression
  • Scoliosis
  • Pediatrics