Comparison of surgical site infection rates in clean and clean-contaminated wounds in dogs and cats after minimally invasive versus open surgery: 179 cases (2007-2008).

OBJECTIVE: To report and compare the surgical site infection (SSI) rates for clean and clean-contaminated procedures performed by either a minimally invasive surgical or open surgical approach in a large population of dogs and cats.
DESIGN: Prospective case series. ANIMALS: 179 patients (dogs and cats) undergoing minimally invasive abdominal or thoracic surgery. PROCEDURES: Case information from all animals that underwent minimally invasive abdominal or thoracic surgery was prospectively collected and compared with an existing database of the same information collected from 379 patients undergoing laparotomy or thoracotomy via an open surgical approach. For both groups, an SSI was defined as any surgical wound in which purulent discharge was observed within 14 days after the procedure. Follow-up for all patients was obtained by direct examination or telephone interviews.
RESULTS: Overall SSI rate in the minimally invasive surgery (MIS) group was 1.7% and in the open surgery (OS) group was 5.5%. On univariate analysis, there was a significantly lower SSI rate in the MIS group, compared with the SSI rate for the OS group. On multivariable logistic regression analysis, this difference appeared to be a result of the fact that surgery times were longer (median, 105 vs 75 minutes) and hair was clipped ≥ 4 hours prior to surgery for more animals (23% vs 11 %) in the OS group, compared with the MIS group. CONCLUSIONS AND CLINICAL RELEVANCE: MIS may be associated with a lower SSI rate, compared with OS, but confounding factors such as differences in surgery time and preoperative preparation contributed in part to this finding. As such, surgical approach cannot be categorized as an independent risk factor for SSIs in small animals until further studies are performed.