Vaginal Support The salient points of pelvic organ prolapse (see Chapter 27 for patients with defecatory dysfunction are the support of the vaginal apex, posterior wall, and perineal body, although some experts believe anterior wall defects can also affect defecatory dysfunction. The posterior wall is assessed while supporting the vaginal apex and anterior wall with a Sims speculum. This permits the examiner to focus on identifying specific locations of rectovaginal fascial defects. A rectovaginal examination aids in identification of defects in the rectovaginal fascia or perineal body. Loss of vaginal rugation has also been reported overlying the site of a rectovaginal fascial tear (84). This technique is especially useful for enteroceles, which have a smooth, thin epithelium over the enterocele sac or peritoneum.
Normally, the perineum should be located at the level of the ischial tuberosities, or within 2 cm of this landmark. A perineum below this level, either at rest or with straining, represents perineal descent. Subjective findings of perineal descent include widening of the genital hiatus and perineal body, as well as a ﬂattening of or a convex appearance of the intergluteal sulcus. Women with perineal descent also tend to have less severe stages of pelvic organ prolapse based on the Pelvic Organ Prolapse Quantification (POP-Q) staging system because it measures descent from the hymenal ring (85). An increase in the length of the perineal body and genital hiatus consistent with straining suggests perineal descent. The degree of perineal descent can also be measured objectively with a St. Mark’s perineometer, although a thin ruler placed in the posterior introitus at the level of the ischial tuberosities also can be used. Descent is measured as the distance the perineal body moves when the patient strains. Although pelvic ﬂoor ﬂuoroscopy is the standard technique for measuring perineal descent, this technique is most useful in patients with symptoms of severe defecatory dysfunction and evidence of perineal descent on pelvic examination.
Anorectal Examination Visual and digital inspection of the vagina and anus will help to identify structural abnormalities such as prolapse, fistulas, fissures, hemorrhoids, or prior trauma. As previously mentioned, a rectovaginal examination provides useful information regarding the integrity of the rectovaginal septum and can demonstrate laxity in the support of the perineal body. The rectovaginal examination is helpful in the diagnosis of enteroceles, which can be felt as protrusion of bowel between the vaginal and rectal fingers with straining. Digital rectal examination should be performed at rest, with squeeze, and while straining. The presence of fecal material in the anal canal may suggest fecal impaction or neuromuscular weakness of the anal continence mechanism. Circumferential protrusion of the upper rectum around the examining finger during straining suggests intussusception, which often occurs in combination with laxity of the posterior rectal support along the sacrum.
The integrity of the external anal sphincter and puborectalis muscle can be evaluated by observation and palpation of these structures during voluntary contraction. Evidence of dovetailing of the perianal skin folds and the presence of a perineal scar with an asymmetric contraction often indicates a sphincter defect. When a patient is asked to contract her pelvic ﬂoor muscles, two motions should be present: The external anal sphincter should contract concentrically, and the anal verge should be pulled inward. These actions should also be apparent on digital rectal examination. As mentioned previously, the 90-degree angle created by the puborectalis should be readily palpable posteriorly and, with voluntary contraction, the examining finger should be lifted anteriorly toward the pubic rami. Both the puborectalis and external anal sphincter should relax during Valsalva effort. Patients with anismus may experience a paradoxical contraction of these muscles during straining. Finally, defects in the anterior aspects of the external anal sphincter may be detected by digital examination.