So the Bone Flap Hit the Floor, Now What? An In Vitro Comparison of Cadaveric Bone Flap Decontamination Procedures.

Background and objectives: Over the course of their career, 66% of neurosurgeons will witness someone accidentally dropping a bone flap on the floor during a craniotomy procedure. Although this event is rare, it can have significant consequences for the patient, and little literature is available to guide management of this complication. Our objective was to compare 5 bone flap decontamination protocols for efficacy in reducing bacterial load, with the goal of safely reimplanting the dropped flap.

Methods: Cadaveric human bone flaps were contaminated with common operating room (OR) contaminant bacteria. The bone flaps were then subject to 1 of 5 decontamination protocols: washing in saline, mechanical debridement, washing in antibiotics, washing in alcoholic chlorhexidine antiseptic, and flash decontamination in autoclave. Inoculum from the flaps was then used to grow bacteria in petri dishes, and bacterial load after decontamination was assessed. Some flaps were physically dropped on an OR floor to simulate and evaluate a real-life contamination.

Results: The observed contamination from a flap dropped on an OR floor can be significant (up to 1070 colony-forming units cultured per flap). All protocols tested decreased bacterial load of the bone flaps to different degrees: saline by 95.7%, mechanical debridement by 97.5%, antibiotic bath by 99.5%, alcoholic chlorhexidine by 99.9%, and flash sterilization by 100.0%. Flash sterilization led to significant alterations in the flap's physical appearance.

Conclusion: In the event of the accidental fall of a bone flap, decontamination by rinsing in an alcohol-chlorhexidine solution followed by 3 successive washes in saline seemed to provide the best balance between effectiveness, safety, and complexity of the method.