Accurate anatomic repair of obstetric anal sphincter damage or rectovaginal fistula aided by prior ultrasonograghy : a cohort study

Abstract

BACKGROUND : Anorectal obstetric injuries resulting in anal sphincter damage (ASD) and rectovaginal fistula (RVF) remain a major problem. The resulting flatus or faecal incontinence is devastating. Surgical repair remains a challenge. Postpartum RVF primarily results from ischaemic pressure necrosis following obstructed labour. The fistula tract is surrounded by a fibrous scar. ASD usually results from precipitous labour. The injury heals by fibrous scar leading to varying degrees of anal incontinence. Contraction and retraction of muscles around the injury renders the defect and fibrous scar larger than the primary injury. Anorectal ultrasonography has been used to define RVF and ASD, and the associated fibrous scar. PATIENTS AND METHODS : A retrospective review of patients who underwent transvaginal surgical repair of RVF and ASD was undertaken. Patients were preoperatively assessed for pathology and incontinence degree. Anorectal ultrasonography was used to define ASD or RVF and the associated scar preoperatively. Repair of RVF or ASD entails total excision of the scar with accurate anatomical layers reconstruction of healthy tissues. RESULTS : There were 23 patients, 8 RVF with a mean (SD) age 29 (6.78) years and 17 ASD with a mean (SD) age 35.25 (15.90). Twenty followed obstetric trauma (6RVF, 14 ASD), 1 prior rectocoele repair (ASD), 2 rape (1RVF + 1 ASD) and 1 was idiopathic (RVF). All patients had 1 or more prior repairs except for idiopathic RVF. Operative technique entailed transvaginal complete excision of the fibrous scar and accurate anatomical reconstruction of healthy tissue layers. A colostomy was not routinely used. There were three significant postoperative complications: ASD breakdown from an infected haematoma; perianal abscess, later a sinus after drainage; and RVF repair dehiscence during early coitus. All patients had full continence after 8 months minimum follow-up. CONCLUSION : Complete excision of the fibrous scar and accurate anatomical tissue layers reconstruction of the obstetric RVF or ASD, aided by prior ultrasonography, yielded good results.