Predictors of Curve Progression in Spinal Deformity Associated with Hydromyelia and Chiari I Malformation

Purpose: We designed a retrospective callback study to investigate (1) the factors that could predict whether a particular spinal deformity might progress despite neurosurgical management of syringomyelia/Chiari I malformation and (2) the results and complications from orthopaedic treatment of the spinal deformity.

Methods: 17 patients with spinal deformity who had neurosurgical management of associated syringomyelia and/or Chiari I malformation were evaluated by history, physical examination, review of plain radiographs and MRI. We studied the treatment effects of syrinx drainage alone, spinal fusion, combined procedures, and non-operative measures. We analyzed presenting, preoperative and most recent curve patterns, residual spinal deformity, residual neurological deficits and morbidity of surgical intervention. Patients were divided into two groups: those whose curves progressed after neurosurgical intervention (“progressors”) and those whose curves stabilized or decreased (“non-progressors”).

Results: 10 children in the “progressors” group had neurosurgery at an average age of 10.8 years (range 3-18) and were followed for 7.1 years (range 2-10). 7 “non-progressors” had neurosurgery at 7.4 years (range 5-11) and were followed for an average of 5 years (range 3-7). Neurosurgical procedures and technique were equivalent in both groups, however surgical revisions seemed to be more common in the “progressors” group. All “progressors” had a double scoliosis curve (mean 52o, range 16o-72o), but only 28% of “non-progressors” had a double curve (mean 28o, range 16-40). A sagittal deformity was present in 71% of “progressors”, but not in “non-progressors”. Neurological findings were initial findings in 75% of “progressors” 38% had unbalanced curves (>2cm). 28% of “non-progressors” presented with neurological findings and all had well balanced curves (<1.5 cm).

Conclusions: In this series, progression of spinal deformity after satisfactory neurosurgical management of syringomyelia /Chiari I malformation was associated with later age at neurosurgical decompressions and initial neurological symptoms, double scoliosis curve patterns, sagittal deformity, out-of-balance curves and larger curve at presentation.