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Patients with anorectal incontinence have weakness of the anal sphincter muscles. Most of these patients also have damage to the nerves of the sphincter muscle. A post-anal repair procedure was devised to relieve fecal incontinence by tightening the pelvic floor muscles and the anal sphincter. This procedure is helpful in about 60 percent of patients. The effect of this repair on anal sphincter muscles and the nerves that stimulate them was investigated. Physiological evaluation of the sphincter and pelvic floor muscles was carried out on 18 patients. These evaluations were performed before surgery and 9 to 35 months postoperatively. Following surgery, 13 of the patients (72 percent) were improved; five had good results (no incontinence or only minor staining) and eight had fair results (improved but with some incontinence or liquid stool). Electrophysiological studies showed increased nerve damage after surgery, even in those patients who were functionally improved. Patients in the unimproved category (five subjects) showed marked neurologic abnormality with only a few motor potentials recorded in the anal sphincter. It is possible that the postanal repair may speed up the neurogenic damage to the muscles of the pelvic floor and sphincter, which normally occurs slowly. This may be responsible for the poor functional outcome of some patients. (Consumer Summary produced by Reliance Medical Information, Inc.)

A study was done in 1983 that described the changes found in the muscles and nerves in the pelvic area of 122 women during the two-month period after childbirth. It was found that 80 percent of women giving birth for the first time sustained some reversible nerve damage. Because the findings were potentially important in understanding stress incontinence (inability to control the anal sphincter under physical stress), it was decided to recall some of these women. Since there is evidence that women who have given birth more than once are prone to develop incontinence, all of those women, in particular, were recalled. The recall was five years after the original study. Twenty-four women were contacted and 14 agreed to be re-examined. Five of the 14 women who had had more than one child developed incontinence five years later as compared with none of the controls; two of them had had another child during the five years. These findings suggest that vaginal delivery causes nerve damage that persists and may worsen over time, possibly leading to symptoms of incontinence. (Consumer Summary produced by Reliance Medical Information, Inc.)

Constipation and defecation straining have been implicated in the pathogenesis of anorectal incontinence. We have studied 24 women with chronic constipation and 20 age- and parity-matched control subjects. Electrophysiologic techniques were used to study the innervations of the puborectalis and external anal sphincter muscles. The results show that damage can occur to the nerve supply of both these muscles in chronic constipation, and that this probably is due to perineal descent during defecation straining.

In the author's opinion, post-anal repair remains the procedure of choice for patients with levator neuropathy and loss of anorectal angle. The operation is minimally invasive and relatively free of major complications. A knowledge of the anatomy of the perineum and in particular of the intersphincteric space is mandatory before undertaking such surgery. Any surgeon who is accustomed to performing internal anal sphincterotomy will already be accustomed to identifying the plane and the internal sphincter. Progression to performing post-anal repair is only a small step. On the other hand, gracilis transposition seems to be a procedure of considerable technical complexity. Also it must be difficult to gauge the tension of the repair correctly. Presumably it can be all too easy to make the repair too tight and cause a stricture or create a lax repair by leaving too long a length of tendon. However, in patients whose pelvic floor has failed to develop (e.g., in patients with rectal atresia) it is hard to imagine any procedure other than gracilis transposition which can possibly be considered. Clearly, post-anal repair in this case would be contra-indicated.