Lumbar Degenerative Spondylolisthesis Changes in Surgical Indications and Comparison of Instrumented Fusion With Two Surgical Decompression Procedures

Study Design. Single-center retrospective case series. Objective. To compare outcomes of instrumented fusion and two methods of decompression for degenerative spondylolisthesis. Summary of Background Data. There is no consensus on the surgical indications or optimum techniques for lumbar degenerative spondylolisthesis. Methods. We analyzed the data of 140 patients treated by fusion (n = 80; mean follow-up, 77.9 months) or decompression (n = 60; mean follow-up, 38.0 months) and examined changes in surgical indications over a 12-year period. We compared the outcomes of instrumented fusion with the outcomes of two decompression techniques, the first employing a unilateral approach for bilateral decompression and the second employing a bilateral approach for contralateral decompression, with contralateral foraminal decompression as needed. Postoperative evaluation was made at the final follow-up visit beginning in 2007 by analyzing patient interviews and neurological examination data. We compared results with the Japanese Orthopedic Association symptom score before surgery and at final follow-up. Results. Surgical indications for fusion narrowed over time, with fusion used less frequently and decompression used more frequently. Similar decreases in clinical symptoms, including low back pain, were achieved with all methods. In the decompression groups, preoperative slip distance and instability, and postoperative slip progression or development of instability, did not correlate significantly with clinical outcome. Slip progression occurred in 8 of 10 levels in patients with preoperative translation >= 5 mm, but these patients showed no increase in instability, defined as translation >= 2 mm, at final follow-up. Conclusion. Our findings raise a question about the value of the radiologic criteria for performing fusion used in the late period, namely translation >= 5 mm and/or rotation >= 10 degrees. If discogenic pain is excluded, decompression alone may be suitable even for patients with severe low back pain and translation >= 5 mm.