The effectiveness of surgical correction of postpartum anal incontinence in the presence of a functional neurogenic component

AIM: to evaluate the functional state of the anal sphincter and pudendal nerve conduction in patients with postpartum traumatic anal sphincter incontinence (AI), and to analyze the correlation between the clinical severity of AI according the Wexner scale.

PATIENTS AND METHODS: the prospective cohort study included three centers. The study enrolled patients with postpartum AI scheduled for surgical sphincter repair as the primary treatment stage (June 1, 2025, to October 31, 2025). Endpoints were the clinical severity of AI (Wexner scale) pre- and post-surgery, the functional state of the anal sphincter complex via anorectal manometry, and the terminal motor latency (M-response) of the external anal sphincter during pudendal nerve stimulation (PNTML) prior to surgery. Changes in Wexner scores were analyzed relative to PNTML values, alongside the overall correlation between functional diagnostic parameters and perioperative AI severity.

RESULTS: thirty-nine patients were analyzed. Preoperatively, the median Wexner score was 11.0 (Q1-Q3 9.0–15.0). Comprehensive sphincterometry revealed a median resting pressure (MRP) of 33.0 (29.0–36.0) mmHg and a median maximum squeeze pressure (MSP) of 74.0 (63.0–87.0) mmHg. Stimulation electromyoneurography (ENMG) showed preserved motor fiber conduction (PNTML) in 11 patients (28.2%): median values were 2.1 (1.8–2.3) ms on the right and 2.3 (1.8–2.4) ms on the left. Normal latency was detected in 11 patients (28.2%), unilateral latency prolongation in 14 (35.9%), and bilateral prolongation in 14 (35.9%) patients (median: right 3.1 [2.7–3.8] ms; left 2.9 [2.6–3.4] ms). Postoperatively, the median Wexner score for all patients improved to 2.0 (1.0–4.0). Significant improvements in continence were detected across all subgroups: in patients with normal M-responses, the median score decreased from 10.0 (8.0–15.0) to 1.0 (0.0–1.0) (p = 0.0038); in those with unilateral prolongation, from 12.0 (10.0–16.0) to 2.0 (2.0–5.0) (p = 0.0011); and in those with bilateral prolongation, from 11.0 (9.0–14.0) to 2.5 (2.0–5.0) (p = 0.0058).

CONCLUSION: functional studies of the anal sphincter complex in patients with post-traumatic AI are essential for predicting the outcomes of sphincteroplasty and ensuring a comprehensive, individualized approach to treatment selection. The presence of a neurogenic component in the pathogenesis of AI does not preclude the high efficacy of surgical correction; however, it plays a significant role in determining a combined treatment strategy. Furthermore, the effectiveness and clinical necessity of neurostimulation as an adjunctive therapy following sphincterolevatoroplasty warrant further investigation.

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