Survivorship analysis of laminectomy with or without fusion for spinal stenosis or degenerative spondylolisthesis: a national retrospective cohort study

Background Lumbar spinal stenosis and spondylolisthesis are common degenerative problems. The benefits of decompressive laminectomy are proven, however, there is debate on whether laminectomy plus fusion is superior. Importantly, the addition of fusion results in longer hospital stays, and increased costs. Long term follow-up in prospective trials is challenging for this population and therefore there is little evidence on longer term mortality following surgery. The objective of this study was to evaluate the survival of patients undergoing laminectomy with or without fusion for lumbar spinal stenosis or spondylolisthesis, and to consider the association between patient factors and surgical procedure. We also investigated differences in survival based on diagnosis. Materials and Methods This was a population level retrospective cohort study. This study evaluated 56, 520 patients undergoing inpatient surgery for degenerative conditions of the lumbar spine from the Canadian Research Data Centre Network’s Dalhousie University Atlantic Research Data Centre holdings. Statistics Canada was uniquely linked with the Discharge Abstract Database to establish survivorship. Kaplan-Meier analyses were performed to establish survivorship curves. Databases did not control for frailty or comorbidity. Results Patients with spondylolisthesis had a small survivorship advantage at 5- and 10-years post operation (94.8%, 83.8%) compared to those with spinal stenosis (91.2%, 76.5%). However, for both spinal stenosis and spondylolisthesis, there was no difference in survival regardless of treatment. However, younger age was associated with increased rates of fusion both within and between groups (p < 0.001). For patients with spinal stenosis, we also found that female sex and rural status were associated with increased survival regardless of surgical procedure (p < 0.001). Conclusion There is no difference in survival for patients undergoing laminectomy with or without fusion for lumbar spinal stenosis and degenerative spondylolisthesis. Thus, the clinical benefit of the addition of fusion to laminectomy for degenerative lumbar spine conditions remains unclear and warrants further consideration and investigation.