Outcomes after decompression surgery without fusion for patients with lumbar spinal stenosis and substantial low back pain. 
The aim of this study was to evaluate the efficacy of decompression surgery alone for patients with intolerable low back pain.  We retrospectively identified 222 patients who underwent spinal decompression without fusion surgery who had substantial preoperative low back pain (preoperative numerical rating scale score ≥ 5).  Their clinical outcomes were assessed using the numerical rating scale and the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) preoperatively and at 3 months and 1 year after surgery.  At 3 months and 1 year after surgery compared with baseline, there was a significant improvement in the overall mean numerical rating scale scores for low back pain (baseline = 6.8, 3 months = 2.1, 1 year = 2.7), leg pain (6.8, 2.1, 2.7), and leg numbness (6.4, 2.9, 3.2) (P < 0.05).  The efficacy rate assessed by JOABPEQ was 68.1% for pain-related disorders, 47.0% for lumbar spine dysfunction, 63.3% for walking ability, 48.2% for social life dysfunction, and 21.6% for psychological disorders.  When patients were classified into three groups depending on their degree of leg pain (mild, moderate, and severe), there was no significant difference in the efficacy rate between the three groups.  Decompression surgery can improve low back pain, regardless of the degree of preoperative leg pain, but the average score for LBP and leg pain slightly worsened between 3 months and 1 year after surgery.  These slides can be retrieved under Electronic Supplementary Material.