Effect of TYRX Antimicrobial Envelope Use During Sacral Neuromodulation Implantation

INTRODUCTION: Sacral neuromodulation (SNM) is a well-established, minimally invasive therapy for the treatment of bowel and urinary dysfunction. SNM implantation carries the risk of postoperative surgical site infections (SSI s), as well as associated device explant or reoperation. Historically, mesh envelopes for antibiotic delivery have been utilized during implantation of cardiac electronic devices. The TYRX envelope, a Medtronic product, is a dissolvable mesh pouch used to locally deliver minocycline and rifampin. TYRX technology has been shown to reduce infection rate when used for cardiac electronic devices, and limited data suggests its utility when used for implantation of SNM devices. OBJECTIVE: The primary objective was to compare the rate of postoperative SSI and device explant in cases with and without TYRX envelope use. METHODS: This was a retrospective cohort study utilizing the Premier Healthcare Database. Patients were identified as having undergone SNM placement between January 2016 and March 2020 using CPT codes. The patients were grouped by those who received a TYRX envelope and those who did not, as identified by TYRX charge code. Patient characteristics, surgical information and postoperative complications within 3 months and 1 year were collected. Antibiotic administration at time of placement was categorized as cephalosporins, current AUA guidelines (Gram positive + broad Gram-negative coverage), or Other. Patients with and without TYRX charge code were matched via greedy nearest neighbor matching using a propensity score calculated from baseline characteristics. RESULTS: The study included 250 patients with TYRX envelopes and 250 matched patients. After propensity score matching, the groups were statistically similar based on demographics, preoperative characteristics and preoperative antibiotics. There were a total of 2 postoperative SSI in the group without TYRX and 0 in the group with TYRX, but no statistically significant difference in SSI noted between groups (p=0.48). Patients without TYRX were more likely to have undergone SNM removal at 3 months (7.6% vs. 1.2%, p=0.001) and 12 months postoperatively (10% vs. 1.6%, p<0.001). CONCLUSIONS: TYRX envelope use at time of SNM implant is not associated with a reduction in surgical site infections but is associated with a reduction in SNM removal within 1 year (Table 1).