Surgical evaluation and management of lumbar synovial cysts: the Mayo Clinic experience.

OBJECT: The authors report a retrospective analysis of 194 patients surgically treated at their institutions for symptomatic lumbar synovial cysts from January 1974 to January 1996.
METHODS: Patient characteristics including age, sex, symptoms, signs, and preoperative neuroimaging studies were reviewed. Surgical procedures, complications, results, and pathological findings were correlated with preoperative assessment. One hundred ninety-four patients were surgically treated for symptomatic lumbar synovial cysts. Eighty percent were diagnosed and treated between 1987 and 1996. There were 100 men and 94 women with an average age of 66 years (range 28-94 years). The most common symptoms were painful radiculopathy (85%) and neurogenic single or multiroot claudication (44%). However, sensory loss (43%) and motor weakness (27%) were also presenting symptoms. Eleven percent of patients had undergone previous lumbar surgery prior to being referred to the Mayo Clinic. Preoperative neurological examination demonstrated motor weakness (40%), sensory loss (45%), reflex changes (57%), and variants of cauda equina syndrome (13%). In 19% of patients, normal neurological status was demonstrated. There was equal left/right-sided laterality, and eight patients presented with bilateral synovial cysts. The most commonly affected level was L4-5 (64%). All patients underwent laminectomy and resection of the cyst. Concomitant fusion was performed in 18 patients in whom clinical evidence of instability had been observed. However, subsequent fusion was required in only four patients who developed symptomatic spondylolisthesis. Surgery-related complications included cerebrospinal fluid leak (three patients), discitis (one patient), epidural hematoma (one patient), seroma (one patient), and deep vein thrombosis (one patient). One patient died 3 days after surgery of cardiac dysrhythmia. Follow-up data obtained for at least 6 months postoperatively were available in 147 patients. Of these, 134 (91%) reported good relief of their pain and 82% experienced improvement in their motor deficits.
CONCLUSIONS: Lumbar synovial cysts are a more common cause of lumbar radicular pain than previously thought. Surgical removal of the cyst is a safe and effective treatment for symptomatic relief in patients with lumbar synovial cysts. A concomitant fusion procedure may be performed in select cases. In this study, only a few patients developed symptomatic spinal instability requiring a second operation.