What is the Role of Anorectal Physiology Testing and Imaging in the Era of Sacral Neuromodulation? A Single-Center Experience and Literature Review

Background We aimed to investigate the association between preoperative anorectal physiology testing (APT) and outcomes of sacral neuromodulation (SNM) for fecal incontinence (FI). Methods This is a retrospective review of a prospective database of patients with FI who underwent SNM (2011-2020). Patients who underwent at least one preoperative APT were in the preoperative test group, those not tested served as controls. The Wexner/Cleveland Clinic Florida-Fecal Incontinence Score (Wexner/CCF-FIS) was calculated before implantation and at last follow-up. Preoperative workup included anal manometry (AM), electromyography (EMG), pudendal nerve terminal motor latency (PNTML), anal ultrasound (AUS), and defecography (DG). Primary outcome was treatment success, defined as at least 50% reduction from baseline on the Wexner/CCF-FIS at last follow-up. Results 102 patients (mean age: 62.7 ± 13.9 years; 94 (92.2%) female) were included. Median preoperative Wexner/CCF-FIS was 18 (IQR: 15-20), which decreased to 10 (IQR: 4-15) at last follow-up. Anal manometry was performed in 55 (53.9%), AUS in 74 (72.5%), PNTML in 71 (69.6%), EMG in 76 (74.5%), and DG in 28 (27.5%). The overall success rate was 49%; median follow-up was 56 months (IQR: 23.25-79). Overall rates of 30-day complications, device explantation, and redo SNM were 19.6, 3.9, and 5.9%, respectively. 30-day complication rates were 25% in patients without any preoperative testing and 18.3% in those who received at least one preoperative test. Conclusions Routine preoperative APT was not associated with clearly better outcomes after SNM; however, the non-randomized nature of the study, selective test ordering, and limited sample size preclude definitive conclusions of absence of clinically relevant associations.