Cost-effectiveness of Antibacterial Envelope for Sacral Neuromodulation Infection Prevention

Infections following sacral neuromodulation (SNM) implantation are associated with significant morbidity, device explantation, and increased health care costs. Use of an antibiotic-impregnated envelope may reduce this risk, but its cost-effectiveness remains uncertain.

The objective of this study was to determine whether universal or selective (salvage) use of an antibiotic envelope is a cost-effective strategy for preventing infections during SNM implantation.

A Monte Carlo cost-effectiveness analysis (10,000 iterations) using a decision-analytic Markov model was developed from a third-party payer perspective. Three strategies were compared: (1) no envelope, (2) salvage use during reimplantation after infection, and (3) universal use at all SNM implants. The model incorporated costs, utilities, and clinical transition probabilities over a 3-year horizon. A willingness-to-pay threshold of $100,000 per quality-adjusted life year was applied. Sensitivity analyses, including 2-way threshold and probabilistic simulations, evaluated model robustness.

Salvage envelope use was cost-effective with a minimum infection reduction of 0.54%, preventing 1 infection per 186 implants. Universal use became cost-effective at a 1.58% infection reduction (1 infection per 64 implants) or with a price decrease of $42.47 from the $895 base-case. Probabilistic sensitivity analysis favored salvage use in 55.2% of simulations and universal use in 44.8%. The "no envelope" strategy was rarely preferred.

Selective use of the antibiotic envelope during reimplantation is cost-effective under current pricing. Universal use may become cost-effective with modest improvements in infection prevention or reduced cost. These findings support data-driven use of the envelope and may inform clinical guidelines and pricing policy.