Mortality after lumbar fusion surgery.

Study Design: Retrospective population-based cohort study.

Objective: To describe mortality after lumbar fusion surgery in Washington State workers' compensation claimants in the perioperative period and beyond.

Summary Of Background Data: Although lumbar fusion surgery can be associated with serious complications, perioperative mortality is generally considered rare. Population-based mortality estimates have been limited to surgery in older adults.

Methods: We identified all Washington State workers' compensation claimants who underwent fusion between January 1994 and December 2001 (n = 2378) and assessed the frequency, timing, and causes of death. Mortality follow-up was concluded in 2004. Death was ascertained from Washington State vital statistics records and from the workers' compensation claims database. Poisson regression was used to obtain age- and gender-adjusted mortality rates. Years of potential life lost, percent of potential life lost, and mean potential life lost were calculated for the leading 5 causes of death and we calculated the risk of death associated with selected predictors.

Results: Among the 2378 lumbar fusion subjects in the study cohort, 103 were deceased by 2004. The 3-year cumulative mortality rate was 1.93% (95% confidence interval, 1.41%-2.57%). The 90-day perioperative mortality rate was 0.29% (95% confidence interval, 0.11%-0.60%). The risk of perioperative mortality was positively associated with repeat fusions. The age- and gender-adjusted all-cause mortality rate was 3.1 deaths per 1000 worker-years (95% confidence interval, 0.9-9.8). Analgesic-related deaths were responsible for 21% of all deaths and 31.4% of all potential life lost. The risk of analgesic-related death was higher among workers who received instrumentation or intervertebral cage devices compared with recipients of bone-only fusions (1.1% vs. 0.0%; P = 0.03) and among workers with degenerative disc disease (age- and gender-adjusted mortality rate ratio, 2.71) (95% confidence interval, 1.17-6.28). The burden was especially high among subjects between 45 and 54 years old with degenerative disc disease (rate ratio, 7.45).

Conclusion: Analgesic-related deaths are responsible for more deaths and more potential life lost among workers who underwent lumbar fusion than any other cause. Risk of analgesic-related death was especially high among young and middle-aged workers with degenerative disc disease.