CHIARI-I MALFORMATION ASSOCIATED WITH SYRINGOMYELIA AND SCOLIOSIS

Study Design. A retrospective review of a series of 12 children who un derwent suboccipital foraminotomy and duroplasty for Chiari I malforma tion. Objective. To assess the effects of this surgery on associated s yringomyelia and scoliosis. Summary of Background Data. Suboccipital f oraminotomy for the treatment of syringomyelia associated with Chiari I malformation was greatly stimulated by Gardner's hydrodynamic theory , and its results proved to be encouraging. However, several authors r eported improvement or stabilization of associated scoliosis after thi s surgery. Methods. A retrospective review was conducted on 12 patient s who underwent suboccipital foraminotomy for Chiari I malformation as sociated with syringomyelia. Neurologic impairment, extent of syringom yelia, and severity of associated spinal deformity were assessed preop eratively and at a 4.5-year: average follow-up (range, 2.1-12 years). Anomaly of superficial abdominal reflexes was round in all cases, and para or tetraparesis in three cases. Syringomyelia was of variable loc alization and extent. Scoliosis was present in 7 cases (great er than 40 degrees in 5 cases). Results. Diminution or complete disappearance of syringomyelia was observed in 11 cases, 3 months to 1 year after su rgery. Superficial abdominal reflexes anomaly improved in four cases. Minimal neurologic deficit persisted in one case. Scoliosis improved i n one case, remained unchanged in one case, and progressed in the five cases with preoperative severe deformity, requiring instrumentation a nd fusion. Conclusions. Improvement of syringomyelia and neurologic de ficit, observed with suboccipital foraminotomy, supports the theory th at abnormal hydrodynamics of the cerebral spinal fluid is most likely to cause these deficits.