Postoperative Antibiotics

Surgical site infections (SSIs) are an important cause of patient morbidity and mortality in veterinary and human surgical practice. However, conflicting evidence exists in both veterinary and human medicine regarding the effects of empirical postoperative antimicrobial therapy.

This randomized, blinded trial compared use of a perioperative and a 5-day postoperative course of antibiotics to perioperative antibiotics alone in dogs undergoing clean orthopedic surgery using implants. Enrolled dogs (n = 400) were  divided into 2 groups: those receiving both peri- and postoperative antibiotics and those receiving only perioperative antibiotics. Data were also analyzed for tibial plateau leveling osteotomy (TPLO) vs other implant procedures. Short-term (2 and 6 week) and long-term (>1 year) follow-up was obtained by examination or client questionnaire. The short-term infection rate was 3.54% for dogs treated with postoperative antibiotics compared to 5.24% not treated. Long-term (n = 182 dogs), 8.24% of dogs treated with postoperative antibiotics developed SSI compared to 7.22% not treated. No significant difference in SSI rates was noted between groups at any time point or when comparing TPLO surgery vs other surgical procedures using implants.

Commentary

Several recent studies specifically focused on TPLO surgery have reported a protective effect of postoperative antimicrobials on SSI in dogs. This contradicts the historic body of literature and past guidelines for perioperative antimicrobial use only. However, these reports have been uncontrolled retrospective studies, and SSI pathogenesis in orthopedic surgery is likely multifactorial. This study suggests a 5-day postoperative antibiotic course does not reduce the incidence of short- or long-term SSI in dogs. Further work is necessary to understand if other methods of antiseptic prophylaxis or operative strategies are beneficial in limiting the impact of SSI in patients.—Jason Bleedorn, DVM, DACVS