The posterior sagittal approach to anorectal malformation (ARM) has radically changed the outcome of these patients, improving the preservation of anal sphincters, owing to their anatomical identification. However, in long term follow-up, fecal incontinence and severe constipation remain the most frequent and disabling postoperative clinical problems, with an important impact on quality of life. A cluster of physical and psychological problems appear in pediatric patients, including repeated infections, skin ulcer and scar, social anxiety disorder, behavioral problems, self-abasement or isolation and other problems, which cause children full of guilt and embarrassment and increase the risk of bullying.

Current therapeutic measures for FI include biofeedback, sacral nerve stimulation, radiofrequency energy delivery , surgical treatment, and sphincter replacement. Zhengwei Yuan et al. conducted a follow-up study on 31 patients with FI after ARM, and confirmed that biofeedback combined with SNS has a good effect on patients with FI after ARM. However,not all patients improve their impaired anal sphincter and acquire satisfactory continence. A lot of time and treatment costs are wasted. Therefore, it is necessary to clarify the indications for the application of biofeedback combined with SNS.

Severity of ARM affects the degree of development of internal and external anal sphincters. A detailed assessment of anorectal sphincter morphology and function can predict therapeutic outcome. In clinical practice, endoanal ultrasound and endoanal magnetic resonance imaging (MRI) are the main imaging modalities for the anatomical assessment of the anal sphincter complex. Sphincter MR is more suitable for observing the nature of the anal sphincter such as the shape, thickness, directions, and position of the anal sphincter complex and its location on the pelvic floor. MR examination has a high clinical value in the diagnosis of ARM. It can help determine the anal atresia type, display the presence and running of the fistula, evaluate the perianal muscle development and other systems' malformations, and finally provide a reliable diagnostic basis for surgical program and prognostic assessment. The role of MR is similar to that of EUS in some aspects. However, the sphincter MRI can clearly demonstrate the sphincter pattern, the position of the sphincter on the pelvic floor, and several indicators that cannot be detected by EUS. High-resolution anorectal manometry (HR-ARM) is the latest internationally recognized examination for the evaluation of anorectal function. A standardised protocol of HR-ARM can characterise FI from dyssynergic or other neuromuscular and sensory problems.Therefore, HR-ARM provides a more appropriate management in patients with FI. The anorectal manometry is a functional study that can evaluate the potential for muscular sphincterial recovery after BFB; the assessment derives greater benefit also from a morphological evaluation (MRI) in particular when the manometry is unfavorable.

The study included children with FI after ARM, and the investigators combined HR-ARM and MR to predict the efficacy of sacral nerve stimulation and pelvic floor rehabilitation to determine whether patients with fecal incontinence should choose biofeedback therapy.