Functional and quality of life outcomes following obstetric anal sphincter injury (OASI): does the grade of injury affect outcomes?

Introduction and hypothesis: The aim of this study was to compare functional and quality of life data in patients with increasing grades of obstetric anal sphincter injury (OASI) presenting to a tertiary colorectal pelvic floor clinic within 24 months of delivery.

Methods: Prospective data were collected from the patients for the period 2009-2016 and included data on functional outcomes and motor anorectal manometry parameters. The instruments used for the evaluation of functional outcomes were the Birmingham Bowel and Urinary Symptoms Questionnaire, the Wexner Incontinence Score, Short Form 36, and the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire. OASI grade of injury was based on the postdelivery endoanal ultrasound scan. Data from patients with a grade 3a, 3b, 3c or 4 OASI were compared using one-way ANOVA for parametric data and the Kruskal-Wallis test for nonparametric data overall and for separate time periods (3-6 months, 6-12 months, 12-24 months).

Results: Functional patient data were available in 177 patients: 29 with grade 3a, 55 with grade 3b, 77 with grade 3c and 16 with grade 4 OASI. There was no discernible trend in worsening function with increasing severity of OASI overall, nor for the specified time periods of 3-6 months 58 patients), 6-12 months (85 patients) or 12-24 months (18 patients).

Conclusions: Our series demonstrated no significant differences in functional outcomes or quality of life in patients with different OASI grades. Longer-term follow-up is required to ascertain any later functional differences which may become apparent with time.