Elderly, or other medically high-risk patients are usually treated by perineal procedures,  as they can be performed under a regional anesthetic, or even local anesthetic with intravenous sedation, thus avoid the risks of a general anesthetic. Alternatively, perineal procedures may be selected to reduce risk of nerve damage, for example in young male patients for whom sexual dysfunction may be a major concern.Perineal rectosigmoidectomy
The goal of Perineal rectosigmoidectomy is to resect or remove the redundant bowel. This is done through the perineum. The lower rectum is anchored to the sacrum through fibrosis in order to prevent future prolapse. The full thickness of the rectal wall is incised at a level just above the dentate line. Redundant rectal and sigmoid wall is removed and the new edge of colon is reconnected (anastomosed) with the anal canal with stitches or staples. This procedure may be combined with levatorplasty, to tighten the pelvic muscles. A combined a perineal proctosigmoidectomy with anterior levatorplasty is also called an Altemeier procedure. Levatorplasty is performed to correct levator diastasis which is commonly associated with rectal prolapse. Perineal rectosigmoidectomy was first introduced by Mikulicz in 1899, and it remained the preferred treatment in Europe for many years. It was Popularized by Altemeier. The procedure is simple, safe and effective. Continence levatorplasty may enhance restoration of continence (2/3 of patients). Complications occur in less than 10% of cases, and include pelvic bleeding, pelvic abscess and anastomotic dehiscence (splitting apart of the stitches inside), bleeding or leak at a dehiscence Mortality is low.
Later, the mass may have to be pushed back in following defecation. This may progress to a chronically prolapsed and severe condition, defined as spontaneous prolapse that is difficult to keep inside, and occurs with walking, prolonged standing, coughing or sneezing (Valsalva maneuvers). A chronically prolapsed rectal tissue may undergo pathological changes such as thickening, ulceration and bleeding.If the prolapse becomes trapped externally outside the anal sphincters, it may become strangulated and there is a risk of perforation. This may require an urgent surgical operation if the prolapse cannot be manually reduced. Applying granulated sugar on the exposed rectal tissue can reduce the edema (swelling) and facilitate this. Cause
The precise cause is unknown, and has been much debated. In 1912 Moschcowitz proposed that rectal prolapse was a sliding hernia through a pelvic fascial defect.This theory was based on the observation that rectal prolapse patients have a mobile and unsupported pelvic floor, and a hernia sac of peritoneum from the Pouch of Douglas and rectal wall can be seen. Other adjacent structures can sometimes be seen in addition to the rectal prolapse. Although a pouch of Douglas hernia, originating in the cul de sac of Douglas, may protrude from the anus (via the anterior rectal wall), this is a different situation from rectal prolapse. Shortly after the invention of defecography, In 1968 Broden and Snellman used cinedefecography to show that rectal prolapse begins as a circumferential intussusception of the rectum, which slowly increases over time.