Irradiated allograft bone in spine surgery: to culture or not? A single center retrospective study.

Study Design: Retrospective chart review.

Objective: We aimed to document the rate of infection in our institution after the use of irradiated cancellous allograft or iliac crest bone autograft in vertebral fusion procedures. We also reviewed the pertinence of microbiological culture of cadaveric allograft bone prior to its implantation.

Summary Of Background Data: Recent studies have shown similar postoperative infection rates between allograft and autograft. The pertinence of microbiological culture of allograft bone prior to its implantation is currently controversial.

Methods: Retrospectively, we identified 338 patients who underwent spine fusion procedures for which there was a minimum of a 1-year follow-up. Files from both the neurosurgery and orthopedics divisions of the Centre hospitalier universitaire de Sherbrooke were reviewed during 1999 to 2009. Irradiated allografts were used in 164 patients and autografts were used in 174 patients. Of the 164 allografts implanted, 53 were cultured peroperatively. Postoperative spinal infection was based on documented positive spine cultures at the time of re-exploration for presumed infection. Infection rates were compared using Fisher exact test.

Results: From the 53 peroperative cultures, 5 were positive (9.4%) and none of them led to antibiotherapy or surgical revision at 1 year. No significant difference was observed in the rate of surgical site infection at 1 year, after the use of irradiated allografts (1.8%) or autografts (1.7%), P = 1.0.

Conclusion: Perceived association with infection should not influence the surgeon in bone graft choice for spinal fusion. There is a lack of scientific evidence to recommend for or against routine cultures on allograft implantation in the literature. Our results strongly underline the pertinence of larger multicenter clinical trials to assess the pertinence of peroperative allograft bone culture.