[Surgical treatment of syringomyelia]

Eighty cases of surgically treated syringomyelia were retrospectively reviewed. The cases were classified into following 4 types, type 1: syringomyelia with Chiari malformation (54 cases), type 2: syringomyelia with basal arachnoiditis (15 cases), type 3: syringomyelia with an obstruction of the foramen Magendie (1 case), and type 4: syringomyelia with spinal arachnoiditis (14 cases). Foramen magnum decompression (FMD) was performed in patients with type 1, in type 2 fourth ventricle-subarachnoid shunt was additionally performed. Gardner's operation was performed in patients with type 3. Syrinx-peritoneal shunt was performed in patients with type 4. Surgical procedures for syringomyelia which we selected were thought to be appropriate, based on postoperative syrinx collapse rate in MRI. However, postoperative clinical course was much different in each type of syringomyelia after the collapse of syrinx had been equally achieved. Neurological disorders were stopped in deterioration after surgery in all cases of type 1. However, motor weakness was still deteriorated in half cases of type 2, and in 60% of type 4. When clinical severity of the patients with type 1 and 2, based on the distribution of dissociated sensory loss and motor weakness, were classified into 5 grades. The rate of improvement of patient's symptoms and signs was higher in the lower grades. We concluded that a surgical treatment for syringomyelia was essentially a preventive one, therefore it should be done in early stage of disorders.