Benefit of a single dose of preoperative antibiotic on surgical site infection in varicose vein surgery.

BACKGROUND: Ligation and division of the saphenofemoral junction (L/D SFJ) can protect against the danger of venous thromboembolism (VTE) associated with greater saphenous vein (GSV) radiofrequency ablation (RFA). Although this procedure is regarded as clean from an infection standpoint, surgical site infection (SSI) can offset its thromboembolic benefit. We questioned whether SSI associated with L/D SFJ could be minimized by a single preoperative dose of antibiotic.

METHODS: A retrospective cohort study was performed on 902 ambulatory surgery patients who underwent 953 consecutive RFAs of the GSV in combination with L/D SFJ. A single dose of preoperative antibiotic was administered 1 hour before incision to some patients (n = 449 extremities), with all other patients receiving no antibiotic (n = 504). Primary outcome measure was SSI categorized based on type of therapy required (1: oral antibiotic, 2: hospitalization for intravenous antibiotic and/or wound debridement), with a secondary outcome measure of VTE.

RESULTS: VTE occurred in 10 patients (1%) and included three pulmonary emboli. The majority of VTE were calf deep vein thromboses (n = 7). SSI developed in 78 patients (8.2%) with groin, thigh, and calf distributions of 47%, 8%, and 45%, respectively. All category 2 infections (n = 8, 10%) occurred in control subjects, and the majority were located in the groin. Body mass index significantly increased risk for both overall (odds ratio [OR]: 1.09, 95% confidence interval [CI]: 1.05-1.14, P < 0.0001) and groin (OR: 1.08, 95% CI: 1.02-1.14, P = 0.01) SSI as well as VTE (OR: 1.17, 95% CI: 1.08-1.30, P = 0.003). Diabetes was a significant risk for groin SSI (OR: 5.13, 95% CI: 1.44-18.26, P = 0.01). Antibiotic was associated with a significantly reduced risk for both overall (OR: 0.54, 95% CI: 0.37-0.89, P = 0.02) and groin (OR: 0.34, 95% CI: 0.16-0.73, P = 0.01) SSI. Furthermore, prophylaxis eliminated category 2 infections (P = 0.008) and was associated with a significantly lower risk of VTE (OR: 0.11, 95% CI: 0.01-0.85, P = 0.01). Although SSI was noted more commonly in extremities with thromboembolic complications (20% [n = 2] vs. 8.1% [n = 76] in those without), this trend was not significant and could not account for the antibiotic effect on VTE.

CONCLUSIONS: L/D SFJ combined with RFA of the GSV, when treated as a clean procedure and not prophylaxed with antibiotic, carries a significant risk of SSI. While diabetes and high body mass index are patient-associated SSI risk factors, a single dose of preoperative antibiotic significantly reduces the rate of all infection, eliminates the danger of serious infection, and is associated with minimal VTE.