Surgical Site Infection Rates by Specialty for Patients Who Undergo Sacral Neuromodulation Surgery

INTRODUCTION: Sacral neuromodulation (SNM) is an FDA-approved treatment for a variety of conditions including urinary and fecal incontinence, urinary frequency, urgency, and retention. Surgical site infection (SSI), estimated to occur in 2–11% of cases, is a serious complication as it often necessitates explantation. There are limited studies evaluating preoperative and postoperative antibiotic use. OBJECTIVE: The purpose of this study was to describe a perioperative regimen employed within the division of urogynecology at our institution compared to other departments. METHODS: This was a retrospective chart review of the electronic medical record (EMR) for all female patients at our institution ≥18 years old who underwent sacral neuromodulation between 1/1/2013 and 12/31/2022. Subjects were identified from the EMR using a query of Current Procedural Terminology (CPT) codes 64581, 64590, and 64595. All subjects had a postoperative evaluation within 90 days of procedure. Women were excluded if they had incomplete EMR documentation or did not undergo stage 2 procedure. The primary outcome was SSI within 90 days of surgery. Perioperative antibiotic regimens were compared between three specialties performing SNM surgery: urogynecology and reconstructive pelvic surgery (URPS), colorectal surgery (CRS), and urology. RESULTS: A total of 447 cases were eligible for inclusion. URPS performed the majority of cases (50.6%, n=236). CRS and urology performed 175 and 36 cases, respectively. The lowest infection rate, 2.5%, was in URPS patients and increased to 4% for CRS and 5.6% for urology (Figure 1). For preoperative antibiotics, CRS and urology predominantly used single-agent cefazolin. URPS predominantly used gentamicin plus vancomycin (66.1%), a practice change from single-agent cefazolin in 2017. Irrigation of the implant pocket was described in 100% of URPS cases, 83.9% of urology cases, and 47.4% of CRS cases with gentamicin/saline being the irrigant of choice for all 3 specialties. Review of postoperative oral antibiotics showed 70.8% of URPS cases were prescribed trimethoprim/sulfamethoxazole or cephalexin on discharge, and only 41.7% and 18.9% of urology and CRS cases, respectively, were discharged with any postoperative prophylaxis. Within the URPS division, we identified trends in SSI as standard of care evolved. Prior to January 2017, our preoperative regimen of single-agent cefazolin yielded an SSI rate of 4.62%. With a change to gentamicin plus vancomycin in January 2017, SSIs dropped to 3.4%. With a switch from cephalexin to trimethoprim/sulfamethoxazole for postoperative prophylaxis in July 2019, SSIs further decreased to 0.9% (Figure 2). CONCLUSIONS: In this single-institution retrospective chart review for surgical site infection after SNM, we found varied perioperative antibiotic regimens. SSI was least common with URPS surgeons when compared to urology and colorectal surgeons. Lowest rates of SSI were found with preoperative gentamicin plus vancomycin, implant pocket irrigation with gentamicin/saline, and postoperative oral antibiotics with MRSA coverage. These findings show that our current perioperative regimen leads to very low SSI rates after surgical implantation of a sacral neuromodulator.