Levator plate function may be important in maintaining fecal continence after obstetric anal sphincter injury repair: a pilot perineal and endovaginal ultrasound analysis

Background: Fecal Incontinence (FI) following Obstetric Anal Sphincter Injuries (OASI) and repair is under constant investigation. Ultrasound is reliable in identifying Levator Ani Muscle (LAM) morphology and malfunction. Objective: To investigate the incidence of levator plate dysfunction by pelvic floor ultrasound in patients with OASI repair and to correlate with patient-reported outcomes. Methods: A prospective cohort study of patients who had sustained OASI in one year. We reviewed the computerized files to obtain obstetrics variables. We invited OASI patients to undergo anal manometry, 2D Endovaginal, and 2D perineal, and to complete outcome questionnaires at a 6–12-month follow-up. We measured by Ultrasound the distances between the Levator Plate (LP) and Pubic bone (LP-P) and LP and vaginal probe (LP-V) at rest and during squeeze, with delta calculations for these distances (∆ LP-P and ∆ LP-V). Results: 27 patients completed the study. 15% had FI. All FI patients also had flatus incontinence compared with 8% of FC (p 0.001). The patient’s age, long second stage of labor, and high newborn weight were correlated with FI. LP-P resting and LP-P squeeze distances were larger among the FI (p 0.01 for both). LP-V resting and LP-V squeeze were more significant among the FI group (p 0.07, < 0.001). ∆ LP-P was significantly greater among the FC than the FI (0.01). Conclusions: Patients with normal levator plate function had FC following OASI repair. Given the small sample size, a firm conclusion about FI cannot be reached, but notably, the few patients with FI after OASI repair had abnormal LAM function.