Comparison of Short-Term Clinical Results and Radiologic Changes Between Two Different Minimally Invasive Decompressive Surgical Methods for Lumbar Canal Stenosis

There were no significant differences in clinical outcomes and radiological changes except for disc height between the lumbar spinous process-splitting laminectomy and trans-interspinous lumbar decompression (TISLD) groups at short-term follow-up. Removal of interspinous contextures in TISLD might be more likely to cause disc height loss when applied at the L4/5 level. Study Design. A multicenter, retrospective study. Objective. To clarify the clinical and radiological effects of removing interspinous contextures in lumbar decompression surgery for patients with lumbar spinal stenosis. Summary of Background Data. There have seldom been reports that have compared both clinical results and radiological changes among minimally invasive decompression methods. Methods. Consecutive 52 patients underwent lumbar spinous process-splitting laminectomy (LSPSL), following which 50 patients underwent trans-interspinous lumbar decompression (TISLD). All patients presented with cauda equina type of lumbar spinal stenosis and underwent a minimum 1-year follow-up. The Japanese Orthopaedic Association (JOA) score and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) score were evaluated to determine the extent of daily living activities. Propensity score (PS)-matched analysis was used to match patients’ age and preoperative JOA scores between the two groups. Lumbar lordosis (LL), disc height (DH), segmental range of motion (ROM), and vertebral anterior translation were measured by functional lumbar lateral x-ray, and changes between preoperative and 1-year postoperative values were evaluated. Results. Twenty-nine pairs of patients were selected by PS-matching. Mean JOA scores increased from 14.4 to 23.5 (mean recovery rate was 62.3%) in the LSPSL group and from 14.0 to 23.2 (61.3%) in the TISLD group at preoperative and 1-year follow-up, respectively. There were no significant differences in clinical results and changes in LL, ROM, and vertebral anterior translation in each group. The DH at L4/5 level at 1-year after surgery revealed significant decrease in the TISLD group compared with the LSPSL group. There was a correlation between preoperative DH and DH decrease in the LSPSL group, but not in TISLD group. Conclusion. Removal of interspinous contextures did not influence clinical outcomes at 1 year after surgery, but it may be likely to cause disc height loss when it applied at the L4/5 level. Level of Evidence: 3