OBJECTIVETo assess the clinical outcomes of Coflex interspinous dynamic internal fixation and the imaging changes for degenerative lumbar spinal stenosis.

METHODSFrom October 2007 to February 2009, 30 patients with degenerative lumbar spinal stenosis were treated with Coflex interspinous dynamic internal fixation, including 17 males and 13 females with an average age of 45 years (range, 39 to 65 years). The operation level at L4,5 were 20 cases, L5S1 9 cases and 1 case was in both the two levels. The ODI scores and JOA questionnaires were assessed before and after operation. The radiological measurement included ventral and dorsal intervertebral space height, segmental intervertebral angles formed by lines drawn on the upper and lower endplates of the instrumented and adjacent levels on flexion-extension radiographs; the area of spinal canal, dural sac, the sagittal and transverse diameter of the spinal canal and dural sac on CT scan. All the patients were treated with limited laminectomy and were implanted with Coflex device.

RESULTSAll the patients were followed up for 5 to 19 months. There were significant differences in the ODI scores and the JOA questionnaires by paired t-test (P<0.01). All the patients were satisfied with surgical outcomes except 3 patients whose pain were not obviously relieved and need drugs or block therapy; 3 patient complaining of progressive hypoesthesia. There were no complications associated with the Coflex device. The height of dorso-intervertebral disc was increased obviously while the range of motion in adjacent levels was not increased on flexion-extension radiographs; the area of spinal canal and dural sac were significantly increased.

CONCLUSIONIt shows a good clinical result to release the degenerative lumbar spinal stenosis symptoms and decrease short-term complications by using Coflex device. It is available for patients with increasing the intervertebral space, area of spinal canal and preventing the adjacent segment degeneration.