Definition

A rectocele is an abnormal protrusion of the anterior rectal wall into the vagina ( Fig. 24-1 ). It is found in 20% of adult women, and symptoms may develop by the fourth or fifth decade of life. Most rectoceles protrude less than 2 cm into the vagina, are incidental findings, and require no treatment.

Anatomy of a rectocele.

(From Ferri FF. Ferri’s Color Atlas and Text of Clinical Medicine . Philadelphia: Saunders; 2009.)

Rectoceles can be graded according to size. A grade I rectocele protrudes part way into the vagina; in a grade II rectocele, the bulge reaches the introitus, and a grade III rectocele is visible outside the vaginal opening.

Causes

The exact cause of rectoceles is unknown; however, several hypotheses have been proposed. In the past, obstetric injuries and multiple vaginal deliveries were thought to be the main precipitating factors, but such patients have been shown to have a prevalence comparable with nulliparous women. In a recent study, 370 symptomatic women (e.g., women experiencing excessive straining, vaginal splinting, and the sensation of incomplete evacuation) aged 13 to 91 years were assessed using three-dimensional anorectal ultrasound. The prevalence of rectoceles was 65% in nulliparous women, 70% in women with at least 1 vaginal delivery, and 71% in women who had undergone cesarean sections. No correlation was found between vaginal deliveries and pelvic floor dysfunction.

Currently, the most commonly accepted theory for the formation of rectoceles is the pressure gradient formed between the rectum and vagina during defecation. This is accentuated by the increased straining caused by obstructed defecation, the most common cause of which is paradoxical contraction of the puborectalis muscle. Straining leads to an increased pressure gradient across the rectovaginal septum and promotes the formation of rectoceles.

A study of 45 patients with obstructive defecation and rectocele noted that severe constipation (Cleveland Clinic Constipation Score >15) was the only factor associated with the presence of a rectocele. In fact, persons with hypotonia of the sphincter muscles (<40 mm Hg) had a lower prevalence of rectoceles. In another study of 487 patients evaluated by ultrasound and manometry, no correlation was noted between the size of the rectocele and the number of deliveries or frequency of irritable bowel syndrome symptoms. Dysfunctional defecation, also known as “nonrelaxing puborectalis muscle syndrome,” was noted in 60% of persons with a rectocele compared with 24% of persons without a rectocele. However, no specific anorectal physiologic findings were associated with rectoceles.

Rectoceles are often associated with other pelvic disease. Rectal intussusception or prolapse, the second most common cause of obstructed defecation, is found in roughly two thirds of patients with rectoceles. Given the tendency to strain at defecation, it is not surprising that vaginal and/or uterine prolapse, enterocele, and excessive perineal descent are also found.

Symptoms

The most common symptoms are the feeling of incomplete evacuation and the sensation of a vaginal or perineal bulge. The associated obstructed defecation causes prolonged straining at stool and a sensation of blockage upon defecation. Many women with symptomatic rectoceles find that manual splinting via pressure on the perineum or inside the vagina helps facilitate defecation. Some women also report dyspareunia, anorectal/vaginal pain, urologic symptoms, and occasionally fecal soiling.

Diagnosis

The first step in diagnosis is to obtain a thorough history. Questions regarding bowel function (e.g., constipation, continence), childbirth, dyspareunia, urologic symptoms, and additional maneuvers performed to assist in defecation (as previously mentioned) are all relevant. The Cleveland Clinic Constipation Score or the Knowles-Eccersley-Scott Symptom questionnaire can be administered as part of the baseline evaluation and can be helpful when performed after interventions to assess symptom improvement.

Upon digital rectal examination, a finger is gently pressed against the anterior rectal wall. A rectocele is felt as a weakness that allows the finger to pass through the normal position of the rectovaginal septum into the vagina, just above the sphincter mechanism. With a grade III rectocele, the examining finger will be seen in the introitus.

Video defecography (VDG) using oral and rectal contrast material has proved to be the most helpful diagnostic test by providing an assessment of rectocele size and the ability to empty with normal defecation; it also documents other disease such as paradoxical puborectalis contraction, rectal prolapse, intussusception, and sigmoidocele/enterocele. A rectocele is considered clinically significant if it measures greater than 3 cm on VDG or has retention of barium or stool after evacuation of the rectum.

Magnetic resonance imaging provides good visualization, and if it is performed as a dynamic study, it can correlate the rectocele with pelvic floor movements. Images caught during defecation can identify abnormal bladder, vaginal, or rectal descent. However, magnetic resonance imaging scans are generally performed with the patient supine, which is a nonphysiologic position for assessing defecation; these scans are also more expensive and often miss the diagnosis of enteroceles. The newer modality of three-dimensional anorectal ultrasound correlates closely with VDG and may help delineate the pelvic floor. Anorectal manometry, measurements of pudendal nerve terminal motor latency, and endoanal ultrasound are important for assessing anal neuromuscular function and associated sphincter defects. In general, VDG is the most helpful and accurate test in evaluating overall pelvic floor function.