Are prophylactic antibiotics routinely necessary in laparoscopic adnexal surgery? A multicenter cohort study

The benefit of routine prophylactic antibiotics for clean laparoscopic adnexal surgery remains unclear. We evaluated whether pre-incision cefazolin reduces the incidence of 30-day surgical site infections (SSIs), and we identified perioperative risk factors for SSIs.

We conducted a multicenter retrospective cohort study using clinical data from Osaka University and six affiliated hospitals. Among 1,865 patients who underwent laparoscopic adnexal surgery for benign conditions, 1,678 were included after specified exclusions. Patients received either pre-incision cefazolin (n = 1,415) or no prophylaxis (n = 263) according to institutional policy. The primary outcome was the incidence of SSI during the 30-day postoperative interval, classified according to CDC criteria. The association between prophylaxis and SSI was evaluated using inverse probability of treatment weighting (IPTW). Propensity scores were estimated using age, body mass index, diabetes mellitus, endometriosis, and previous abdominal surgery. Risk factors for SSI were assessed using multivariable logistic regression analysis. Exploratory subgroup analyses were performed by repeating the same IPTW procedure within specified subgroups, and procedure-specific supplementary analyses were performed for ovarian cystectomy.

SSI occurred in 1.1% of patients in both groups: 16/1,415 in the cefazolin group and 3/263 in the non-antibiotic group. In IPTW-adjusted analyses, the incidence of SSI did not differ between groups (1.1% vs. 1.2%; p = 0.915). In multivariable analysis, operative time ≥120 min was associated with SSI (adjusted odds ratio [aOR] 3.54, 95% confidence interval [CI] 1.41-8.85). In supplementary analyses restricted to an ovarian cystectomy subgroup, uterine manipulator use was associated with SSI (aOR 4.03, 95% CI 1.26-12.90).

Routine prophylactic cefazolin was not associated with a significantly lower incidence of 30-day SSI after clean laparoscopic adnexal surgery. Given few SSI events and the potential for residual confounding, our findings support further evaluation of a selective rather than routine approach to prophylactic antibiotic use.