Abstract

Background: Minimally invasive decompression has provided satisfactory outcomes with limited slip progression for Lumbar Spinal Stenosis (LSS) with Degenerative Spondylolisthesis (DS). However, how slip progression stops, its impact on clinical symptoms, and whether the patient’s sex affects these post-decompressive conditions remain unknown. This study aimed to answer these questions and investigate the effectiveness and limitations of decompression alone for LSS with DS.

Methods: We carried out a prospective study which enrolled 99 patients who had LSS with DS at L4/5. Of these, 10 dropped out and 6 required reoperation, leaving 83 patients who underwent microscopic decompression. A 2-year follow-up was carried out. The Japanese Orthopedic Association (JOA) score and visual analog scale for back pain and leg symptoms were used for clinical evaluation. The slip rate (% slip) in the neutral, flexion, and extension positions; the absolute difference in the % slip between flexion and extension; and the range of motion were used for radiographic evaluation. A repeated-measures two-factor ANOVA was carried out to determine the differences in each parameter between the sexes and across three different time points (before, and one and two years after surgery).

Results: The remaining 83 patients showed no interactions between sex and changes in parameters at any time point. The slip progression in each position stopped one year after decompression, with the % slip at the neutral position decreasing 1-2 years after decompression. Mobility did not change, and clinical symptoms improved each year.

Conclusion: The sex of the patient did not affect the post-decompressive course, and slip progression stopped one year after decompression, with no change in mobility. This post-decompressive restabilization can improve clinical symptoms 1-2 years after decompression.

Keywords: Minimally invasive decompression; Lumbar spinal stenosis; Degenerative spondylolisthesis