ANTIBIOTIC PENETRATION INTO CERVICAL DISCS

ANTIBIOTICS ARE FREQUENTLY prophylactically administered in surgical p rocedures to reduce the incidence of infection. The penetration of ant ibiotics into lumbar discs has been studied with mixed results, but pe netration into cervical discs has not been reviewed. In this study, we examined the penetration of two commonly used antibiotics, oxacillin and cefazolin, into cervical discs. Eighteen patients with a total of 30 discs removed were studied. Two groups, each consisting of four pat ients with five discs removed, received either 1 g of oxacillin or 1 g of cefazolin by a single, preoperative intravenous infusion. Two othe r groups, each consisting of five patients with 10 discs removed, rece ived either 2 g of oxacillin or 2 g of cefazolin, also by a single, pr eoperative intravenous infusion. A blood specimen, from which serum an tibiotic levels were determined, was obtained from each patient simult aneously with each discectomy. The time interval between the antibioti c infusion and discectomy/phlebotomy was also recorded. Antibiotic lev els were detected in all discs removed but were quantifiable in only 1 2. Nine of these 12 had been exposed to cefazolin. Of these nine discs , one was from a patient who had received 1 g whereas the other eight were from patients who had received 2 g of cefazolin. This represents 80% of the removed discs exposed to 2 g of cefazolin (10 discs total) and 20% exposed to 1 g (5 discs total). The remaining three discs with quantifiable antibiotic levels had been exposed to 2 g of oxacillin, which represents 30% of the discs (10 total) exposed to that dose of o xacillin. Although cervical disc space infections are rare, they are s erious. This information should be considered by those using prophylac tic antibiotics for invasive cervical disc space procedures.