Observations on spine deformity and syringomyelia.

OBJECTIVE: Spine deformities, notably scoliosis, are known to occur in conjunction with syringomyelia. This study aims to analyze the effect of laminectomies performed in the course of treatment of syringomyelia. It examines the incidence, severity, and type of spine deformity as it relates to the extent and location of laminectomies performed.
METHODS: Records of 169 patients were analyzed for evidence of spinal deformity on imaging studies for the extent of the syringomyelic cavities and for previous surgical procedures on the spine. This analysis included patients with syringomyelia related to Chiari malformation, as well as patients with primary spinal pathology.
RESULTS: Spinal deformities were encountered in 41% of Chiari-syringomyelia patients who had not undergone previous surgery and in 57% of such patients who underwent reoperation. Scoliosis, the most common type of deformity encountered, was likely to be mild in patients who had not undergone previous surgery and severe in reoperated patients. Spine deformity was significantly more common in those patients who had more extensive bone removal.
CONCLUSION: Complete laminectomy should be avoided whenever possible in patients with syringomyelia because local denervation of the axial musculature, added to loss of medial anterior horn cells from syringomyelia, favors the development of spine deformities. This is particularly true of laminectomies performed at the junctional areas of the spine, i.e., cervical-thoracic and thoracolumbar. Hemilaminectomy usually suffices for shunt placement; instrumented stabilization should be considered in patients undergoing full laminectomy, especially those considered to be at high risk of developing deformity.