Topical irrigation with polymyxin and bacitracin for spinal surgery.

Background: The purpose of the present study was to evaluate constant irrigation with saline containing 50,000 units each of polymyxin and bacitracin in a regimen of antimicrobial prophylaxis for clean spinal surgery at two community hospitals with a zero infection rate.

Methods: The focus was on the bactericidal effects of prophylactic topical antibiotics by assessing random contamination in neurosurgical wounds from: 1) the flora of the integument and nares of the operating team, 2) the surgical apparel, 3) the patient's skin, 4) air-borne organisms in the operating theater, and 5) the surgeon's gloves.

Results: Based on individual biotyping of bacteria and antimicrobial sensitivity testing, no consistent source or pattern could be uncovered for the organisms recovered from the operative site. Relying on longitudinal data, the incidence of intraoperative bacterial growth with continuous saline lavage was reduced from 64 to 4% when the combination of topical polymyxin and bacitracin was added.

Conclusions: Although the virtual elimination of bacterial growth in the surgical site was accomplished, the efficacy of topical antibiotics in the prevention of wound infection remains unproven.