Incidence of Surgical Treatments After Obstetric Anal Sphincter Injury

Objectives: To measure the incidence of surgical treatments within one year in postpartum patients with obstetric anal sphincter injury (OASI).

Methods: This is a retrospective analysis of patients from October 2017 to February 2023 who sustained an OASI at childbirth at one of four hospitals in a large academic healthcare institution. All patients with OASI at this institution are referred to a Postpartum Perineal Clinic (PPC). The primary objective of this study was to measure the incidence of surgical treatments within one year in postpartum patients with OASI. Secondary outcomes included describing the indications for surgery and characterizing the types of operations conducted.

Results: Six hundred twenty-three patients sustained an OASI during the study period. The mean age of these patients was 30.9 years (SD 4.5). Most patients identified as white non-Hispanics (n=454, 72.8%%), with a mean body mass index of 30.6 (SD 5.5). The mean gestational age at delivery was 39.1 weeks (SD 1.4). About half of the patients had operative deliveries (n=287, 46.1%), and the majority had a 3rd degree OASI (n=526, 84.4%) (Table 1). The mean vaginal parity after delivery was 1.1 (SD 0.4). Among these patients with OASI, 13 patients had surgical treatment within a year of delivery (2.1%). 14 surgical operations were conducted, as one patient required two surgeries within 1 year of OASI.

In this surgical cohort, all patients were white non-Hispanics, and the majority had an operative delivery (n=12, 92.3%) and a 3rd degree tear (n=11, 84.6%) (Table 2). The most common indication for surgery was persistent pain/tenderness followed by dyspareunia, wound breakdown, rectovaginal fistula, and post-coital bleeding. The most common surgical procedures performed were revision/excision of scar tissue, perineorrhaphy, excision of granulation tissue, revision of obstetric perineal wound disruption/breakdown, and transvaginal rectovaginal fistula repair. The majority of the surgeries were completed within 6 months of delivery (n= 14, 71.4%). There were two complications from these operations: 1) impaired healing and pain necessitating a second surgery, and 2) postoperative cellulitis which was treated with antibiotics. 11 of the 14 total surgeries were performed by urogynecologists.

Conclusions: In this cohort, surgery after OASI was uncommon. However, postpartum patients with OASI should be screened for persistent pain and tenderness, dyspareunia, wound breakdown, rectovaginal fistula, and post-coital bleeding, as these patients may be candidates for surgical treatment and revision. We have a large PPC that allows us to evaluate these operations. Our study adds to the postpartum literature in helping to counsel patients going through childbirth and to enhance the quality of postpartum evaluation, monitoring, and care.