Preoperative Pain Pattern Predicts Surgical Outcome more than Type of Surgery in Patients With Central Spinal Stenosis Without Concomitant Spondylolisthesis: A Register Study of 9,051 Patients.

Study Design. A register cohort study.Objective. To evaluate outcome of surgery for lumbar spinal stenosis without concomitant degenerative spondylolisthesis according to predominance of pain and to analyze the role of spinal fusion in conjunction with decompression in patients with predominant back or leg pain.Summary of Background Data. Predominance of back pain is associated with inferior outcome of surgery for central spinal stenosis (CSS). It is unknown if adding spinal fusion improves outcomes.Methods. In a register study of 9,051 patients we studied outcome of surgery in terms of back and leg pain (VAS), function (the Oswestry disability index and self-estimated walking distance), health-related quality of life (SF-36 and EQ-5D), and patient satisfaction. Outcome was analyzed for 4 groups at 1 and 2 year follow up; preop back pain ≥ leg pain and decompression, preop back pain ≥ leg pain and decompression and fusion, preop back pain < leg pain and decompression, preop back pain < decompression and fusion.Results. Patients with concomitant fusion were younger and had higher back pain and ODI scores and lower preoperative EQ-5D. Predominant back pain was associated with inferior outcome in terms of pain, health-related quality of life and function. Patients most often satisfied (69%) were patients with back pain < leg pain treated with decompression and fusion and the least satisfied group was patients with back pain ≥ leg pain treated with decompression (54%). Fusion was associated with higher EQ-5D at 1-year follow up for patients with predominant back pain up but was also associated with increased leg pain at 2- year follow up in patients with predominant leg pain. Patients with predominant back pain experienced small gains in the physical component summary with fusion.Conclusion. Predominance of back pain is associated with inferior outcome. Adding spinal fusion improves unadjusted outcome but the benefit is small and not clinically significant and generally disappears in the adjusted analysis.