Postoperative culture positive surgical site infections after the use of irradiated allograft, nonirradiated allograft, or autograft for spinal fusion

Study design: Retrospective chart review.

Objective: We report the rate of postoperative infection at our institution following the use of irradiated allograft, nonirradiated allograft, or autograft for spinal fusion procedures.

Summary of background data: Infection after a spinal fusion procedure is a devastating complication. It has not been defined whether spine bone graft preparation has any correlation with postoperative infection in spinal fusion procedures.

Methods: We retrospectively identified 1435 patients who underwent spine fusion procedures with a minimum 1-year follow-up. Irradiated allograft was used in 144 patients, nonirradiated allograft was used in 441 patients, and autograft was used in 850 patients. Postoperative spinal infection was based on documented positive spine cultures at the time of re-exploration for presumed infection. Infection rates were estimated using the method of Kaplan and Meier; estimates were calculated out to 1-year postsurgery, and rates were compared using log-rank tests.

Results: No significant difference in the rate of surgical site infection at 1 year was observed after the use of irradiated allograft (1.7%), nonirradiated allograft (3.2%), or autograft (4.3%), P = 0.51.

Conclusion: There is no significant difference in the rate of infection following spine fusion using irradiated allograft, nonirradiated allograft, or autograft. The selection of bone graft to aid in spinal fusion should be based on the requirements of surgical technique and availability of the desired tissue and not on a perceived association with postoperative infection.