Surgical management of syringomyelia: a five year experience in the era of magnetic resonance imaging.

We summarize our experience with 59 consecutive surgically managed cases of syringomyelia (SM) over a 5 year period. All cases had magnetic resonance imaging (MRI) preoperatively and postoperatively. Twenty-eight patients presented with SM and the adult Chiari (Chiari I) malformation (SM-ACM), 6 patients had post traumatic syrinxes, 14 patients had syrinxes associated with an intramedullary neoplasm, 3 patients had syringomyelia associated with spinal arachnoiditis and 8 patients had idiopathic syringomyelia. Holocord syrinxes were more often associated with SM-ACM, while focal syrinxes were associated with posttraumatic, spinal arachnoiditis and neoplastic conditions. In all cases with neoplasms the MRI revealed parenchymal intramedullary signal abnormalities in addition to the syrinx cavity. Posterior fossa decompression with obex plugging (the Gardner operation) was the procedure of choice for SM-ACM and for idiopathic holocord syringomyelia. Exploration and drainage of the syrinx with or without shunting was carried out mainly for focal syrinxes associated with trauma and neoplasm. Patients with SM-ACM responded well to posterior fossa decompression with satisfactory results in 24/28 patients. Idiopathic SM is probably a forme fruste of SM-ACM and when treated with the Gardner procedure showed good results in all 8 patients. Posttraumatic and neoplastic SM had the least predictable results with surgery. The disappearance of the syrinx on postoperative MRI correlated well with a good surgical outcome.