[Etiology and therapy of rectal prolapse. Experiences with 308 cases 1956-1991].

The cause of a prolapse of the rectum is intrinsic to the organ itself. Neither paralysis of the pelvic floor sphincter complex nor a loosening of the suspending ligaments--which have never been demonstrated in situ--are causative. Determining for the development of a prolapse of the rectum is the break in calibre between the very tight pelvic colon and the wide rectal reservoir. Radiologically we can prove that it is here, where the genesis of prolapse development starts. In comparative anatomy the rectal ampulla is equivalent to the cloaca. Its stable transverse folds (rugae) are reminiscent to the transverse folds of a cloaca anlage, e.g. in the crocodile. A rectal prolapse only includes this cloaca equivalent. For this reason it is never larger than about the size of a fist. Rectosigmoid resection, by removing the calibre break, removes the cause. The involved sigmoid resection also improves the symptoms of constipation. 107 cases operated by peripheral procedures had a recurrence rate of 23.3%, whereas 202 operations removing the calibre break had recurrences in only 3.8% of the cases. Here the calibre break resection has had the best permanent results with a follow-up period up to 30 years.