L4-5 degenerative spondylolisthesis. The results of treatment by decompressive laminectomy without fusion.

The results of the treatment of L4-5 degenerative spondylolisthesis by decompressive laminectomy and partial facetectomy without fusion are presented. Patients who met the following criteria were studied: 1) A slip of at least 10%; 2) No compensation/litigation issues involved; 3) No prior surgery; and 4) Follow-up of at least 18 months. Twenty-four patients with an average follow-up of 34 months (range, 18 to 71 months) are reported. The average preoperative slip measured 7 mm (17%; range, 4-12 mm). Sixteen patients, including all patients less than 60 years of age, underwent preoperative supine lateral flexion-extension radiographs for evaluation of instability. No patient had greater than 2 mm of increase in slip on flexion-extension testing. During decompression, the structural integrity of the pars interarticularis and facet joints are preserved. There were 20 good, three fair, and one poor results. The average postoperative slip measured 8 mm (20%; range, 4-11 mm), and no patient had an increase in slip of greater than 4 mm. In the absence of objective instability on preoperative flexion-extension lateral radiographs in L4-5 degenerative spondylolisthesis, decompressive laminectomy with preservation of the structural integrity of the pars interarticularis and articular processes does not require routine spinal fusion and produced satisfactory clinical results.