Time to Efficacy During Percutaneous Nerve Evaluation Trial: A Retrospective Cohort Study

INTRODUCTION: Percutaneous nerve evaluation (PNE) is a diagnostic tool used to identify patients with urinary incontinence who may benefit from a sacral neuromodulation (SNM) permanent implant. Symptomatic improvement of ≥50% is the established benchmark for a successful PNE study. The speed and predictors of achieving this response are not well defined. OBJECTIVE: To evaluate time trends in urinary symptom improvement during PNE and identify factors associated with ≥50% symptom improvement. METHODS: We conducted a retrospective study of patients with urinary incontinence, with or without concurrent fecal incontinence, undergoing office-based PNE between 2023 and 2025. Demographics along with pre- and post-PNE urinary/fecal urgency, urinary frequency, and incontinence episodes were collected. Outcomes included time to ≥50% improvement in number of incontinence episodes, urgency (on a 4-point Likert scale), and urinary frequency, as well as proceeding to permanent implant. Composite success was measured as time to achieving ≥50% improvement in any one of number of incontinence episodes, urgency (on a 4-point Likert scale), or urinary frequency. Time is defined in days with day 0 being the day of PNE trial initiation. Statistical comparisons were performed between patients who did and did not receive permanent implantation. All PNEs were performed based on landmarks and in the clinic setting. RESULTS: Seventy-five patients were included. Median baseline incontinence was 6 episodes/day, urgency of 3 out of 4, and frequency 10/day. Most patients (95%, n=71) proceeded to permanent implant. Baseline characteristics, including urgency and frequency, did not significantly differ between those who proceeded to permanent implant and those who did not (Table 1). Patients achieving permanent SNM implantation had significantly faster improvement, as measured by fewer days to ≥50% decrease in urinary incontinence episodes (p<0.001), fewer days to maximal improvement in urinary incontinence episodes (p=0.013), and fewer days to achievement of ≥50% decrease in at least one urinary domain (p<0.001) (Table 2). By day 3, 96% of patients who proceeded to permanent implant achieved ≥50% improvement in at least one of the urinary symptom domains (Figures 1 and 2). CONCLUSIONS: Among patients who would proceed to permanent implant, 96% achieved ≥50% improvement in at least one of the urinary symptom domains within 3 days. Baseline clinical features were not predictive of unsuccessful PNE. These findings support the conclusion of PNE trials as early as 3 days post-procedure.Figure 1Figure 2Table 1Table 2