[Anatomically-induced diagnostic and technical surgical problems and complications in surgery of the anorectum]

Preservation and reconstruction are the key principles for surgical therapy of the anorectal organ of continence. The occlusive strength of the sphincter system varies significantly among individuals. As a rule, women have weaker sphincter muscles than men. Both sexes experience a decrease in sphincter strength with age. The physiological weakness of the anorectal sphincters in females is explained by a relatively smaller amount of sphincter muscle mass and an asymmetric sphincter anatomy which is characteristic for the female pelvic floor. In addition, the spinal centers controlling continence are structurally less complex in women than in men. Chronic constipation and the stress of vaginal deliveries frequently cause damage to the pelvic floor in women by overstretching muscular elements. They appear to play a leading role in the development of spontaneous incontinence, a condition occurring exclusively in women. Preoperative assessment of sphincter strength can be accomplished easily by using a very simple measuring device described earlier. Sphincter pressure measurements are felt to be an essential part of any preoperative work-up in anorectal surgery. The numerous procedures described for reconstructing anorectal sphincter function in patients with incontinence are symbolic operations which at the most create an illusion of continence. Narrowing the levator muscles with plastic bands may improve continence if there is some residual sphincter musculature which is still functional. But it will never cure anorectal incontinence. Recommendable procedures for treatment of anorectal prolaps, anorectal fistulas, and hemorrhoids are discussed. Operative treatment of hemorrhoids which are caused by hyperplastic enlargement of parts of the corpus cavernosum recti is also associated with a greater risk of incontinence in women than in men.