Surgical Management of Anal Incontinence Part A. Secondary Anal Sphincter Repair

Lacerations of the anal sphincter or injury to sphincter innervation during childbirth are major causes of fecal incontinence, but the incidence and importance of occult sphincter damage during routine vaginal delivery are unknown. We sought to determine the incidence of damage to the anal sphincter and the relation of injury to symptoms, anorectal physiologic function, and the mode of delivery. We studied 202 consecutive women six weeks before delivery, 150 of them six weeks after delivery, and 32 with abnormal findings six months after delivery. Symptoms of anal incontinence and fecal urgency were assessed, and anal endosonography, manometry, perineometry, and measurement of the terminal motor latency of the pudendal nerves were performed. Ten of the 79 primiparous women (13 percent) and 11 of the 48 multiparous women (23 percent) who delivered vaginally had anal incontinence or fecal urgency when studied six weeks after delivery. Twenty-eight of the 79 primiparous women (35 percent) had a sphincter defect on endosonography at six weeks; the defect persisted in all 22 women studied at six months. Of the 48 multiparous women, 19 (40 percent) had a sphincter defect before delivery and 21 (44 percent) afterward. None of the 23 women who underwent cesarean section had a new sphincter defect after delivery. Eight of the 10 women who underwent forceps delivery had sphincter defects, but none of the 5 women who underwent vacuum extractions had such defects. Internal-sphincter defects were associated with a significantly lower mean (+/- SD) resting anal pressure (61 +/- 11 vs. 48 +/- 10 mm Hg, P < 0.001) six weeks post partum, and external-sphincter defects were associated with a significantly lower squeeze pressure (increase above resting pressure, 70 +/- 38 vs. 44 +/- 13 mm Hg; P < 0.001). There was a strong association (P < 0.001) between sphincter defects and the development of bowel symptoms. Occult sphincter defects are common after vaginal delivery, especially forceps delivery, and are often associated with disturbance of bowel function.

Forty seven healthy young volunteers underwent defecographic examination to determine the range of normal findings. Normality was shown to encompass radiological features often considered pathological. These features included broad ranges of anorectal angle and pelvic floor descent which overlap with reported pathological states. Furthermore, the formation of rectocoeles during defecation was a very common finding in women. Finally, a subgroup of the volunteers had marginal anorectal function. The marginal anorectal function and certain radiological findings such as rectocoeles or intussusceptions may predispose to later problems, or contribute to clinical problems when combined with other factors such as dietary fibre deficiency. The radiological findings raise a number of questions with respect to different aspects of the functioning of the continence and defecation mechanisms.

Anterior structural damage to the anal sphincter occurs in up to a third of women at first vaginal delivery, and of these a third have new bowel symptoms. The standard treatment for such structural damage is anterior overlapping anal-sphincter repair. We aimed to assess the long-term results of this operation. We assessed the long-term results in 55 consecutive patients who had had repair a minimum of 5 years (median 77 months [range 60-96]) previously. Questionnaire and telephone interview assessed current bowel function and continence, restriction in activities related to bowel control, and overall satisfaction with the results of surgery. 42 of these patients had been continent of solid and liquid stool at a median of 15 months after the repair. We were able to contact 47 (86%) of the 55 patients. One of these patients had required a proctectomy and end ileostomy for Crohn's disease. Of the remaining 46 patients, 27 reported improved bowel control without the need for further surgery, and 23 rated their symptom improvement as 50% or greater. Seven patients had undergone further surgery for incontinence and one patient had not had a covering stoma closed. Thus, the long-term functional outcome of the sphincter repair alone could be assessed in 38 patients. Of these patients, none was fully continent to both stool and flatus; only four were totally continent to solid and liquid stool; six had no faecal urgency; and eight had no passive soiling. Of the 38 patients, 20 still wore a pad for incontinence and 25 reported lifestyle restriction. 14 reported the onset of a new evacuation disorder after sphincter repair. 23 of the 46 patients contacted had a successful long-term outcome (defined as no further surgery and urge faecal incontinence monthly or less). The results of overlapping sphincter repair for obstetric anal-sphincter damage seem to deteriorate with time. Preoperative counselling should emphasise that although most patients will improve after the procedure, continence is rarely perfect, many have residual symptoms, and some may develop new evacuation disorders.