A Predictive Model to Identify the Effects of Transcutaneous Sacral Nerve Stimulation With Pelvic Floor Exercises in Fecal Incontinence After Surgery for Anorectal Malformation

Abstract

Objective: While the combination of transcutaneous sacral nerve stimulation (tSNS) and pelvic floor exercises (PFEs) has shown significant effectiveness in treating faecal incontinence (FI) after surgery for congenital anorectal malformation (CARM), not all patients achieve satisfactory continence. Therefore, identifying which individuals will benefit from this method is crucial. Methods: A prospective cohort study enrolled 92 children with FI. All patients underwent tSNS with PFE treatment, and an improved outcome was defined as a Wexner score ≤4. A predictive model to identify the effects of tSNS with PFEs in FI was developed based on the analysis of magnetic resonance imaging and high-resolution anorectal manometry with the area under the receiver operating characteristic curve (AUC) to evaluate the predictive value of external anal sphincter (EAS) thickness index and anal squeezing pressure (ASP). Results: tSNS with PFEs improved outcomes in 72 patients and led to poor outcomes in 20 (4 had their rectums deviate from the puborectalis muscle centre or puborectal muscle ruptures, while 16 lacked EAS with a lower ASP). The AUCs for the EAS thickness index and ASP in predicting tSNS with PFEs effects were 0.915 (95%CI 0.846–0.983, P=0.000) and 0.886 (95%CI 0.819–0.952, P=0.000), respectively. By applying cutoff values of 0.076 for the EAS thickness index and 21.95mmHg for ASP, tSNS with PFEs was found to be ineffective. Conclusions: tSNS with PFEs is effective for most FI patients after CARM surgery except when rectum deviates from the puborectal muscle centre, puborectal muscle rupture occurs, or EAS is absent with a low ASP.