Functional and physiological outcomes following repair of obstetrics anal sphincter injury. A case

Abstract

IntroductionObstetric anal sphincter injury has important psychosocial implications and impact on subsequent pregnancies. Sound operative repair is essential, yet between 14 and 61% patients with obstetric anal sphincter injuries report incontinence symptoms. Objective assessment of the outcome following repair can be performed using anorectal manometry and endoanal ultrasonography. The aim of this study was to assess functional and physiological outcome in patients undergoing operative repair of third or fourth degree tears. MethodsDemographic information and obstetric details were collected retrospectively for patients who sustained a third or fourth degree anal sphincter injury between the periods of 1st January 2008–31st December 2009. All patients were followed up by the Colorectal Nurse Specialist in a dedicated clinic. A detailed history, examination, anorectal manometry (AM) and endoanal ultrasound (EAU) were performed. ResultsOf 210 patients identified data was available for 190 (90%). Median age was 29 years and 74% of the patients were primagravida. Twenty one (11%) patients had grade 3 tear, 81 (43%) grade 3a, 63 (33%) grade 3b, 15 (8%) grade 3c and 10 (5%) patients had grade 4 tears. All patients underwent primary repair: where data was available for operative technique 68 (36%) patients underwent end-to-end and 96 (51%) had overlap repair. 177 (93%) of the repairs were performed by Registrars. Median follow up was 3 months and data was available for 142 (75%) patients. 29 (20%) patients exhibited symptoms of incontinence. Anal resting and squeeze pressure were reduced in patients experiencing incontinence symptoms (66 mHg vs 58 mmHg and 120 mmHg vs 98 mmHg respectively). EAU revealed one EAS (external anal sphincter)/IAS (internal AS) defect, seven IAS defects and 33 thinning of IAS. One quarter of patients with IAS thinning or defect exhibited incontinence symptoms. ConclusionOne fifth of patients experienced some incontinence following repair of obstetric anal sphincter injury, but only 2 patients were incontinent of faeces at 3 month follow up. This represents some improvement in outcome compared to results from the last two decades. Anal pressures in patients experiencing incontinence were reduced, and thinning of the IAS was more common in patients with incontinence symptoms. Efforts to identify occult IAS injury and repair this as well as the EAS may improve patient outcome.