Degenerative Lumbar Spondylolisthesis with Spinal Stenosis: A Comparative Study of 5-Year Outcomes Following Decompression with Fusion and Microendoscopic Decompression

STUDY DESIGN: Retrospective review of prospectively collected outcome data. PURPOSE: To compare 5-year outcomes following decompression with fusion (FU) and microendoscopic decompression (MED) in patients with degenerative lumbar spondylolisthesis (DLS) and to define surgical indication limitations regarding the use of MED for this condition. OVERVIEW OF LITERATURE: There have been no comparative studies on mid- or long-term outcomes following FU and MED for patients with DLS. METHODS: Forty-one consecutive patients with DLS were surgically treated. Sixteen patients first underwent FU (FU group), and 25 then underwent MED (MED group). The 5-year clinical outcomes following the two surgical methods were compared using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire. RESULTS: The degree of improvement (DOI) for social life function was significantly greater in the MED group than in the FU group. Although not statistically significant, DOIs for the other four functional scores were also greater in the MED group than in the FU group. However, patients with a large percentage of slippage in the neutral position might experience limited improvement in low back pain, those with a large percentage of slippage at maximal extension might experience limited improvement in three functional scores, and those with a small intervertebral angle at maximal flexion might have limited improvement in three functional scores after MED for DLS. Therefore, we statistically compared the DOIs between the FU and MED groups regarding the preoperative percentage of slippage in the neutral position among patients with greater than 20% slippage, the preoperative percentage of slippage at maximal extension among patients with greater than 15% slippage, and the intervertebral angle at flexion among patients with angles lesser than −5°; however, there were no statistically significant differences between the two groups. CONCLUSIONS: MED is a useful minimally invasive surgical procedure that possibly offers better clinical outcomes than FU for DLS.