ETIOLOGY

Although some questions have been answered, many aspects of rectal prolapse remain undetermined. Two main theories are known regarding the etiology of prolapse. In 1912, Moschcowitz proposed that rectal prolapse was a sliding hernia that protrudes through a defect in the pelvic fascia at the level of the anterior rectal wall. In 1968, a second theory was proposed by Broden and Snellman, who demonstrated with cinedefecography that full-thickness prolapse starts as an internal intussusception of the rectum with a lead point proximal to the anal verge. This theory was reinforced by Theuerkauf et al. (1970), who used radiopaque markers applied to the rectal mucosa to demonstrate prolapse secondary to intussusception. Today, rectal intussusception is accepted as the mechanism of rectal prolapse.

Various anatomic pathologies related to prolapse include a deep peritoneal cul-de-sac or pouch of Douglas, enterocele, loss of posterior rectal fixation, a patulous anal sphincter, diastasis of the levator ani, redundant rectum and sigmoid colon, and loss of the rectum’s horizontal position, with attenuation of its sacral and pelvic attachments. The ideal rectal prolapse repair should correct as many of these abnormalities as possible. To attain this goal, each abnormality is not addressed individually but addressed in unity by repairing the intussusception itself.

PATHOPHYSIOLOGY

Up to 75% of patients with rectal prolapse are incontinent of stool. The precise pathophysiology behind incontinence is not completely defined, although some causative factors have been identified. Parks et al. (1977) demonstrated histologic evidence of denervation in pelvic muscle biopsies taken from patients who underwent postanal repair, the majority of whom also had rectal prolapse. This finding was confirmed by Neill et al. (1981), who performed electromyographic (EMG) studies of pelvic floor musculature and found denervation in incontinent patients, with and without rectal prolapse, but not in continent patients with rectal prolapse. Some patients with rectal prolapse have abnormal rectal sensation, which may improve following repair. Rectal prolapse itself may directly traumatize the anal sphincters. Anal resting pressures improve in some patients following prolapse surgery.

Constipation affects between 30% and 67% of patients with rectal prolapse. Constipation may be caused by intussusception of the rectum, colonic dysmotility, slow transit, or inappropriate puborectalis contraction. Prolapse repairs may increase or decrease constipation. Speakman et al. (1991) noted that division of the lateral ligaments during surgery appears to increase postoperative constipation, although whether it is due to colonic denervation remains uncertain.

EPIDEMIOLOGY

The incidence and prevalence of rectal prolapse are unknown. It occurs at the extremes of age. Rectal prolapse can be seen in children less than age 3, where malnutrition and cystic fibrosis appear to be predisposing factors. Gender distribution is equal in children. Conservative management is usually successful in treating children with rectal prolapse. In adults, rectal prolapse is more common in women, with a 6:1 female-to-male ratio. Although rectal prolapse can be seen in nulliparous women, it is more common in multiparous women, in whom peak prevalence is after the fifth decade. Men are equally distributed throughout all age groups.

CLINICAL FEATURES

Patients with rectal prolapse usually present with fecal soilage, prolapse of tissue through the anal sphincter complex, mucous discharge, and bleeding. The prolapse is covered with mucosa that can secrete a significant amount of mucus, leading to perianal excoriation and itching. Bleeding is caused by trauma or mucosal venous congestion. Patients with internal (occult) prolapse experience incomplete evacuation of rectal contents, tenesmus, and rectal pain.

Rectal prolapse is associated with comorbidities, including senile dementia, neurologic disorders, infectious disorders, connective tissue disorders, and bulimia nervosa. In addition, rectal prolapse is associated with straining, constipation, previous gynecologic surgery, and anal incontinence. Straining (or other unknown anatomic abnormalities) in men and younger women may push the anterior wall of the upper rectum against the anal canal and cause trauma, leading to ulceration, irritation, and bleeding. This is known as solitary rectal ulcer. At the Cleveland Clinic, Tjandra et al. (1993) reported that 18% of patients with prolapse reported straining and 42% had constipation, consistent with the range of 15% to 65% reported in the literature. Solitary rectal ulcer was found in 12% of patients with rectal prolapse. Previous gynecologic surgery is reported with rectal prolapse; we found that 35% of our patients had undergone a previous hysterectomy, and 38% of our patients were incontinent.

A complete assessment of female patients with rectal prolapse should include evaluation for constipation, urinary and fecal incontinence, and other pelvic floor disorders, such as rectocele, cystocele, and enterocele. Staged or combined surgical correction of pelvic floor disorders may be needed for resolution of the patient’s symptoms.

EVALUATION

Evaluation of patients with rectal prolapse starts with a thorough history and physical examination. The evaluation is important in confirming the diagnosis and in providing information important to decision making for the surgical alternatives. Age, level of activity, comorbid conditions, and living conditions are important issues in determining the type of surgery for an individual. A careful neurologic, obstetric, and surgical history, including hysterectomy and previous prolapse repairs, should be taken in all women. Symptoms related to fecal and urinary incontinence and constipation should be sought.

Occasionally, rectal prolapse is not externally visible on initial examination. A Fleet enema along with straining on the commode may be needed to reproduce the prolapse. Differentiating between full thickness rectal prolapse and hemorrhoidal prolapse is important. A thorough anorectal examination starts with inspection of the perianal skin, looking for signs of excoriation from itching or mucous soiling. The anocutaneous reflex should be tested. Digital anorectal examination includes an assessment for anal sphincter defects, along with resting and squeeze pressures. Occasionally, the prolapsing segment can be felt on digital examination. Associated vaginal prolapse, such as rectocele (posterior vaginal prolapse), cystocele (anterior vaginal prolapse), or enterocele (prolapse of small intestine, usually at the vaginal apex or posterior vagina), should be sought.

Proctoscopy or flexible sigmoidoscopy is needed to exclude the possibility of a neoplasm and allows the opportunity to perform a biopsy on ulcers or other localized inflammation. Because a significant portion of patients with prolapse have associated constipation, incontinence, or other pelvic floor disorders, it is worthwhile to include certain investigational tools in the workup of these patients, if needed. Such tools could include colon transit marker study, defecography, or anal manometry. These must be individualized, however; patients without associated symptoms may not require any further workup besides proctoscopy.

Colonic transit marker studies may be important in patients with severe constipation. This test measures the time it takes for markers to traverse the colon. After patients swallow a set number of radiopaque markers, serial abdominal radiographs evaluate passage of these markers. Patients with prolonged colon transit time may benefit from colon resection with rectal preservation and rectopexy.

When outlet obstruction or pelvic support disorders are suspected, defecography may be obtained. It may show that the sigmoid colon prolapses into the anal canal with straining, or it may show internal (occult) intussusception that does not go through the anal canal.

Anal manometry can be used to evaluate fecal incontinence. Matheson and Keighley (1981) found normal anal pressures in continent patients with rectal prolapse; however, incontinent patients had decreased resting and squeeze anal pressures. Many patients with prolapse-associated fecal incontinence have nerve damage believed to be due to traction injury of the pudendal nerves caused by the rectal prolapse. Continent prolapse patients may not show manometric or EMG signs of denervation. Anal manometry may identify patients who will have improved fecal continence after prolapse repair. Studies from Yoshioka et al. (1989) and Williams et al. (1991) showed that patients who remained incontinent after rectal prolapse repair had significantly lower preoperative resting and squeeze pressures than those whose incontinence improved postoperatively. Other studies, however, dispute the predictive value of anorectal physiology tests. Thus, anal manometry gives preoperative information that may identify patients who will have better outcomes but frequently does not change the clinical approach to the patient.

COMMON SURGICAL REPAIRS FOR PROLAPSE

This comment by Wells of the wide variety of operations for rectal prolapse is a reflection that there is no perfect procedure. Decisions about the appropriate procedure depend on surgical morbidity, risk of recurrence, and consideration of function, including fecal incontinence and constipation. The type of surgical procedure is determined by patient characteristics, such as age, comorbid condition(s), degree of prolapse, and associated pelvic disorders. The goals of surgery are to treat the prolapse and to address associated constipation or incontinence.

The multiple procedures for rectal prolapse can be classified into two main categories: perineal and transabdominal repairs. Perineal repairs are less invasive and cause less morbidity for patients. They are favored for frail elderly patients, but some institutions favor perineal repairs for their healthy patients too. The perineal approach carries the risk of infection and possible complications related to the suture line or wound. Alternatively, abdominal operations are favored by some because prolapse recurrence is less than with perineal procedures. However, the abdominal approach may have complications, such as anastomotic leak, abdominal sepsis, stricture, and adhesions, and usually requires general anesthesia. Therefore, the abdominal approach is reserved for patients who can tolerate laparotomy. The introduction of laparoscopy in the last decade has added a new dimension to prolapse surgery and is showing promise in reducing postoperative recovery time after abdominal repairs.

Our preference for all repairs is to have patients undergo full mechanical bowel preparation. We give perioperative intravenous antibiotics, such as 500 mg metronidazole and a second-generation cephalosporin. For patients allergic to these medications, alternative broad spectrum antibiotics are used to provide prophylaxis against enteric organisms. All patients have a Foley catheter for bladder drainage and pneumatic compression stockings during prolapse surgery.

Perineal Repairs

DELORME PROCEDURE

Although the Delorme procedure was first described in 1900, it was not commonly used until Uhlig and Sullivan reported their experience in 1979. Because the technique is simple and can be done under regional or local anesthesia, it is considered optimal for severely debilitated patients. We prefer to perform the operation with the patient in the prone jackknife position; however, it can also be done in lithotomy position. After the patient is positioned, the perineum and vagina are prepared with an aseptic solution. We use sutures applied in four places around the perianal skin to evert the anus. Other surgeons prefer retractors, such as Lone Star or Hill Ferguson, or Pratt bivalve speculums to enhance visualization. The operation is begun by injecting 1:100,000 epinephrine solution circumferentially into the submucosal plane just proximal to the dentate line. This delineates the dissecting plane and diminishes blood loss. Using electrocoagulation, the dissection starts in a circumferential manner 1 to 1.5 cm above the dentate line (Fig. 27-2), creating a plane between the submucosa and the internal anal sphincter. Once this plane is started, the free edge of mucosa and submucosa is tagged with sutures for ease in handling and creating traction for easier dissection. Continuing in a circumferential direction and using liberal amounts of injectable saline in the plane between the submucosa and the muscular cuff, the surgeon uses scissors to divide the attachments (we prefer fistula scissors) and to deliver the submucosa and mucosal cuff out of the rectum and anus. Penetrating blood vessels encountered during the dissection can be treated with electrocoagulation. Maintaining strict hemostasis is important during the dissection to avoid hematomas after the procedure. The dissection continues until the rectal mucosa cannot be pulled down any further. Usually, 10 to 15 cm can be mobilized. During this phase of the operation, we use copious amounts of antibiotic solution, such as tetracycline, to irrigate the surgical field. After the dissection is completed, the rectal muscle is plicated with suture, such as No. 2-0 Polyglactin 910 suture on a UR-6 needle (Vicryl; Ethicon, Inc., Somerville, NJ). A total of eight sutures are spaced circumferentially for this plication. The dissected mucosa is excised, and the proximal line of resection is approximated to the distal incision line. Interrupted sutures of No. 2-0 Vicryl on a UR-6 needle work well for this circumferential suture line (Fig. 27-3).

Figure 27-2 Incision for a Delorme procedure 1 to 1.5 cm above the dentate line. The incision goes initially through the mucosa and submucosa, stripping the tube from the underlying internal anal sphincter and, more proximally, from the rectal muscular cuff.

(Reprinted with the permission of The Cleveland Clinic Foundation.)

Figure 27-3

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