Unilateral approach for microchannel percutaneous bilateral decompression of lumbar spinal stenosis

Abstract

Objective To evaluate the clinical outcomes and operative techniques of microscopic bilateral decompression for lumbar spinal canal stenosis via the unilateral paramedian approach with tubular retractor system. Methods A retrospective study was conducted to analyze 35 patients with central lumbar spinal canal stenosis who were admitted to Department of Neurosurgery, Affiliated Union Hospital, Fujian Medical University from November 201l to May 2015. Bilateral spinal canal decompression was performed using microchannel percutaneous system through unilateral paraspinal approach and under intraoperative electroneurophysiological monitoring (IOEM). Data including surgical incision, operation time, blood loss volume and IOEM were analyzed. Creatine kinase(CK-MM) levels were measured 1 day before surgery and l day, 3 day as well as 5 days postoperatively. The Japanese Orthopedic Association (JOA) and Visual Analog Scale (VAS) scores were documented at l day preoperatively, and postoperatively at day 1, day 3, day 5, month 1, month 3, month 6 and month 12 months . Lumbar magnetic resonance imaging, computed tomography (CT), and X-ray scan were conducted preoperatively and at 1 month, 6 month and the last follow-up postoperatively. Results The operations were all successfully accomplished with no cases of nerve injury, cerebrospinal fluid leakage (CSFL), postoperative infection or death. The surgical incisions measured 1.5-1.8 cm, the operations lasted 65-110 min, and blood loss volumes were estimated between 8 to 35 ml. The CK-MM level was increased to(461.2±32.6)IU/ml 1 day post-op. with a statistically significant difference compared with pre-op. (P 0.05). At the 12-month follow-up, the JOA score was elevated from (13.4±3.7) to (28.1±0.8)(P<0.05) and the VAS score decreased from (6.9±1.1) to (0.4±0.5)(P<0.05). Postoperative examination of MRI indicated sufficient nerve decompression.No lumbar spinal instability or scoliosis was observed. Conclusion Microscopic bilateral decompression through microelectrode percutaneous approach seems effective for central lumbar spinal canal stenosis with sufficient nerve decompression and less injuries of paraspinal muscles, facet joints, spinous processes and ligaments. This technique offers the advantage of postoperative stability and preserved lumbar mobility. Key words: Lumbar vertebrae; Spinal stenosis; Microsurgery; Unilateral approach; Bilateral decompression