TRENDS IN LUMBAR SPINAL FUSION AND SURGEON FACTORS IN SPINAL STENOSIS SURGERY

Abstract

As the population ages, the prevalence of degenerative spinal conditions is estimated to increase. With soaring healthcare costs, we must be vigilant in our accountability for proper resource allocation to ensure universal access. Significant recent increases in lumbar fusion rates have been observed in the US. Less is known regarding the Canadian experience. Our objective was to evaluate recent trends in lumbar fusion and determine how surgeon factors influence reoperation for spinal stenosis (SS) surgery.

Longitudinal follow-up study of lumbar surgical procedures for SS using administrative databases. Data was gathered on patient-hospital encounters from April 1, 1995 to December 31, 2001. We analyzed trends in spinal fusion. Index procedures (decompressions or fusions) and surgeon variables, such as specialty (orthopaedics, neurosurgery) and volume (above or below thirty cases/year), were selected as predictors of patient reoperation for SS. Adjustments were made for age, gender, and comorbidity. Reoperation rates were evaluated at six weeks, one and two years and until maximal follow-up.

6128 patients were identified (4200 decompressions and 1928 fusions). Proportionally more fusions were performed over the study period when compared to decompressions (1:2.6 in 1995 versus 1:1.5 in 2001). Orthopaedic specialty and higher surgical volume were associated with increased proportion of fusions (p< 0.0001). Reoperation rate was higher for decompressions at two years (OR 1.4) but not at long-term follow-up to ten years. Surgeon specialty had no impact on reoperation rates. Lower surgical volume demonstrated a higher reoperation rate after adjusting for specialty (Hazard Ratio 1.28).

Rates of lumbar spinal fusion have been increasing in Ontario, but at a lesser rate compared with the US. There is wide variation in surgical procedures between surgeon specialty and volume. Surgeon specialty had little impact on reoperation rates. Better long-term survival was observed in spinal surgeons with volumes over thirty cases per year after adjusting for surgeon specialty. Due to increasing rates of spinal fusion, the benefit of improved long-term survival in SS surgery with higher volume surgeons requires more detailed analysis before policy recommendations can be made.