Rectal prolapse is a sign, not a disease. Some of the underlying etiologies include intestinal parasitism, chronic diarrhea, dystocia, or any disease-causing chronic tenesmus, stranguria, or abdominal pressing. Diagnosis is made by visual observation of a red tube-like protrusion of rectal mucosa.
Rectal prolapse must be differentiated from a prolapsed intussusception. The differential diagnosis of rectal prolapse and prolapsed intussusception can be done by placing a finger or blunt instrument such as a thermometer between the prolapsed mucosa and mucocutaneous junction. If resistance is met, the diagnosis is rectal prolapse. If the finger or instrument is easily passed, a prolapsed intussusception is diagnosed.
Rectal prolapse can be managed by several methods including reduction and purse-string suture, amputation, or colopexy. The technique selected depends upon viability of the prolapsed tissue, size and reducibility of the prolapse, and recurrence after a previous technique has failed. In small animal practice, patients with rectal prolapse are generally presented early; before significant mucosal necrosis occurs. Therefore, initial management generally involves reduction and placement of a purse-string suture. This is accomplished by general anesthesia, application of 50% dextrose to reduce mucosal edema, gentle reduction of the prolapsed tissue, and placement of a purse-string suture shows the typical appearance of a rectal prolapse. This suture is tied just snug enough to prevent rectal prolapse yet loose enough to permit defecation. Topical anesthetic ointment (e.g., 1% dibucaine) (Nupercainal ointment, Ciba Pharm, Ciba-Geigy, 556 Morris Avenue, Summit, NJ 67901) is instilled in the rectum postoperatively and continued for two to three days after purse-string removal. The purse-string suture remains for two to three days. Diagnosis and treatment of the underlying cause aids in ultimate success.
A nonreducible viable prolapse or a recurrent rectal prolapse may be treated by celiotomy and colopexy. A ventral midline celiotomy is performed and the prolapse reduced by gentle traction on the colon and concurrent manipulation of the prolapsed rectum.
See the DVD for a detailed video description of the colopexy technique. Once the rectal prolapse is reduced the colon is gently retracted into the abdominal cavity and brought against the left sublumbar body wall. Care is taken to pexy the colon in its ‘functional’ position in the abdominal cavity. Do not place excessive tension on the descending colon during colopexy. The peritoneal surface of the left sublumbar body wall is scarified. A similar sized area of colonic serosa on the antimesenteric border is also scarified. Scarified surfaces of the colon and sublumbar body wall are sutured using a two-layer closure. The dorsal margins of each scarified surface are sutured together first, using a simple interrupted or simple continuous suture pattern with 3–0 or 4–0 synthetic absorbable suture material.
Next, the ventral margins of the scarified surfaces are sutured together in a similar fashion completing the colopexy. Care is taken to make certain sutures do not penetrate the lumen of the colon. Abdominal closure is routine. Topical anesthetic ointment is instilled rectally after surgical correction and continued for five to six days postoperatively.
The prognosis for rectal prolapse is favorable if the underlying problem can be controlled.