Residual defects of the anal sphincter complex following primary repair of obstetrical anal sphincter injuries at a large Canadian obstetrical centre

Abstract Objectives To determine the rates of residual anal sphincter defect following primary repair of obstetrical anal sphincter injury (OASIS), and to assess symptomatology in these patients. Methods A retrospective observational study of patients who underwent primary repair of an OASIS sustained at Mount Sinai Hospital from January 2016 to June 2017. Records were reviewed for demographic and obstetrical data, symptoms of anal incontinence (AI), and the results of endoanal ultrasonography (EA-US). Results One hundred and one women sustained an OASIS during the study period, of whom 53 had EA-US performed at Mount Sinai hospital; 4 women were excluded from this analysis. There were 42 third-degree tears and 7 fourth-degree tears. EA-US revealed residual defects in 22 patients with third-degree tears and 5 patients with fourth-degree tears (52% vs. 71%; P = 0.44).  Twelve patients with third-degree tears and 4 patients with fourth-degree tears reported AI (29% vs. 57%; P = 0.20). EA-US revealed no evidence of a tear in 14 patients clinically diagnosed with third-degree tears and 1 patient clinically diagnosed with a fourth-degree tear (33% vs. 14%). Conclusion These data demonstrate deficiencies in diagnosis and repair of OASIS. Continued training for health care providers on identification and effective repair of OASIS may improve outcomes for women who experience this complication.