Short-term Outcomes of Sacral Neuromodulation for Fecal Incontinence and the Predictive Role of Test Stimulation

This study aimed to evaluate short-term outcomes of sacral neuromodulation (SNM) for fecal incontinence (FI) in a Japanese clinical setting, and to assess the predictive value of response during the test stimulation phase.

We retrospectively evaluated patients with FI who underwent SNM between 2014 and 2024. Patients proceeded to permanent implantation following a 2-week test stimulation. Primary outcomes included changes in weekly FI episodes, Cleveland Clinic Florida Fecal Incontinence Score (CCFIS), Fecal Incontinence Severity Index (FISI), and Japanese Fecal Incontinence Quality of Life Scale (JFIQL). Anorectal manometry data were also assessed. A receiver operating characteristic (ROC) curve was constructed to investigate the predictive utility of test-phase response.

Of 34 patients, 32 (94.1%) proceeded to implantation. Two subsequently required explantation, and 30 completed the 12-month follow-up. At 12 months, median weekly FI episodes decreased from 7.5 to 3.0, CCFIS from 15.0 to 9.0, and FISI from 36.5 to 22.5; JFIQL improved from 2.02 to 2.53 (all p < 0.05). A ≥50% reduction in FI episodes was achieved in 20 of 30 patients (66.7%). Maximum squeezing pressure significantly increased from 90.0 to 107.0 mmHg (p = 0.013), while maximum resting pressure did not change significantly. ROC analysis yielded an area under the curve (AUC) of 0.663, identifying a 36.4% reduction in FI episodes during the test phase.

SNM demonstrated favorable short-term outcomes in Japanese patients with FI, including improved continence, quality of life, and anal sphincter function. Early partial response during the test phase may serve as a useful predictor of sustained benefit.