Unilateral Laminectomy Approach for the Removal of Spinal Meningiomas and Schwannomas: Impact on Pain, Spinal Stability, and Neurologic Results

BACKGROUND: Spinal intradural tumors are usually removed with laminectomy/laminotomy with a midline dural incision. Pain, discomfort, postoperative kyphosis, and instability may be minimized with unilateral microsurgery. METHODS: Seventy patients with schwannoma (73 tumors) and 27 patients with meningioma (29 tumors) were operated on with unilateral hemilaminectomy (June 2000 to March 2014). Surgery was generally kept to 1 or 2 levels, removing all the craniocaudal ligamentum flavum. Careful radioscopic identification is mandatory; in thoracolumbar schwannomas, the tumor may be mobile; in the prone position, it may move cranially than appears on magnetic resonance imaging. The dura was opened paramedially, and the tumor was dissected and removed either en bloc or piecemeal after ultrasonic debulking. Neurophysiologic monitoring was performed. The tumor was approached tangentially with no cord rotation or minimal manipulation. Average duration of surgery was 160 minutes (100-320 minutes). Removal was total in 72 of 73 schwannomas; Simpson grade was 1 in 10 meningiomas and 2 in 19. RESULTS: Patients with no complications were discharged on day 5-7. Ten patients had orthostatic headaches; 2 had pseudomeningocele that required reoperation. Pain improvement (Dennis Scale) was significant either at discharge or at follow-up (P < 0.0001 schwannomas, P < 0.001 meningiomas). Neurologic results (McCormick Scale, Karnofsky Performance Score) were excellent/good: of 39 patients with preoperative neurologic impairment, 19 recovered completely, 17 had minor spasticity, and 3 had moderate spasticity but autonomous ambulation. Sphincters recovered in 5 of 10 patients At follow-up, average Karnofsky Performance Score improved from 60 to 90 (P < 0.0001) and the McCormick score decreased from 121 to 55 (P < 0.0001). No spinal instability was observed. CONCLUSIONS: Neurologic and oncologic results were good and postoperative pain and discomfort were reduced. Stability was preserved with a unilateral technique. No bracing was necessary, permitting early rehabilitation.