Fig. 12.1
A natural increase in intraabdominal pressure during the sensation to defecate exacerbates the enterocele intrusion through the Pouch of Douglas (Reprinted from American Journal of Obstetrics and Gynecology, 180(4), Cruikshank SH, Kovac SR, Randomized comparison of three surgical methods used at the time of vaginal hysterectomy to prevent posterior enterocele, 859–65., Copyright (1999), with permission from Elsevier)
Fig. 12.2
Small bowel herniating through the vaginal apex forming an apical enterocele (Reprinted from American Journal of Obstetrics and Gynecology, 179(6 Pt 1), Miklos JR, Kohli N, Lucente V, Saye WB, Site-specific fascial defects in the diagnosis and surgical management of enterocele, 1418–22, Copyright (1998), with permission from Elsevier)
A brief review of the key supporting structures and potential spaces within the pelvis is important in understanding enterocele defects and in serving as a guide to the appropriate repair. By viewing the pelvis as three compartments: anterior (bladder, urethra), middle (vagina, cervix, uterus), and posterior (anal canal, rectum), we are able to conceptualize pelvic organ prolapse in an organized way. However, it is important not to lose sight of the pathology causative of pelvic organ prolapse. The organ structures are bystanders in the process, though often blamed as the perpetrators. Defects in the pubocervical, endopelvic, and rectovaginal fasciae are the root cause of organ prolapse . Study of the anterior, middle, and posterior compartments will reveal the specific defects present and guide repair.
In the structurally sound pelvis, the vagina is anchored anteriorly to the bladder by the pubocervical fascia and posteriorly to the rectum by the rectovaginal fascia. A natural hiatus is present for the cervix and uterine fundus. The upper quarter of the vagina is suspended by the cardinal-uterosacral ligaments, the middle half by lateral attachments, and lower quarter by the urogenital diaphragm/perineal body fusion plane [8]. These levels correspond to De Lancey’s levels 1, 2, and 3, respectively (see Chap. 3). Failure of any, or a combination, of these levels will cause vaginal vault prolapse and allow the small bowel to occupy the potential space between the vagina and rectum, producing a posterior enterocele. The distinct apical enterocele will occur when the endopelvic fascia overlying the vaginal cuff is disrupted and/or thinned, typically during hysterectomy. The small bowel is then afforded direct contact with the uncovered vaginal epithelium and an apical enterocele occurs [6].
The sensation to defecate is likely created, or contributed to, by the sensation of pressure and stretch of the levator ani musculature. Patients with enterocele experience the herniated small intestine pressing upon the pelvic musculature and anterior rectal wall. This produces the misinterpreted urge to defecate. Subsequent straining at unproductive defecation increases the intraabdominal pressure, intensifying this sensation as the small intestine is pushed more strongly against these receptors. This leads to further attenuation of Denonvillier’s fascia, widening of the Pouch of Douglas , and deepening of the enterocele as symptoms continue to worsen [19]. A simple test is useful in identifying this process. Explain this process to the patient and, at the next occurrence, have the patient leave the toilet and position themselves with hips well above shoulders (i.e., hips elevated on cushions). Relief of the sensation to defecate suggests that gravity has assisted the small intestine in falling out of Pouch of Douglas and predicts success after surgical repair of the enterocele.
Presenting Symptoms
The symptoms of enterocele can be classified into two categories: (1) pelvic discomfort and (2) altered bowel function. Symptoms of pelvic discomfort from an enterocele can include pelvic pain, pressure, a sensation of prolapse/protrusion, and dyspareunia. Symptoms of obstructed defecation are the most common symptoms of enterocele. Patients describe a sensation of a ball in the rectum, which leads them to making several unsuccessful visits to the toilet in an attempt to relieve this sensation. Others will complain of the sensation of incomplete emptying, straining, infrequent bowel movements, or episodes of fecal incontinence. A history of chronic straining and constipation is often present; however, there is some question as to the role of enterocele in causing the symptoms of obstructed defecation and concomitant partial or complete rectal prolapse may be the true cause of the symptoms. This highlights the need for complete pelvic floor evaluation prior to embarking on repair [9]. One study of 310 women with pelvic organ prolapse found no difference in bowel function among those with and without enterocele [10]. Often, the patient will detail a history of chronic constipation that has been present for years, but has more recently become associated with additional pelvic complaints. This supports the notion that functional symptoms are likely due to multiple factors which are gradually worsening and eventually come to the clinician’s attention once they have passed an individual’s pain and bowel function threshold of complaint. By this time, multiple pathologies are likely to be present and the identification and correction of each pelvic compartment is paramount. The history must seek out the symptoms typical of enterocele cited above, as well as other possible contributing factors. Questions regarding urinary incontinence, the presence of a vaginal bulge, difficulty evacuating bowel movements, and rectal prolapse should all be routine. The development of symptoms occurring after hysterectomy should alert the clinician to the possibility of an apical enterocele as the causative agent. Lastly, patients with enterocele and associated obstructed defecation often develop symptomatic anorectal disorders such as hemorrhoids or fissuring and pelvic floor pathology may prove to be the unifying diagnosis .
Diagnostic Evaluation
Physical Examination
A thorough, focused pelvic exam with the intent of uncovering pathology in all compartments is paramount. The pelvic exam should evaluate the anterior and posterior vaginal walls, cervix, urethra, rectum, anus, and perineum. This is usually achieved in the lithotomy position; however, subsequent bimanual exam for enterocele may be better achieved in standing position. After static exam is performed, the patient should be asked to strain and each component evaluated with attention to cervical descent, cystocele, perineal descent, rectal prolapse, rectocele, and presence of a patulous anus. During bimanual exam, the examiner should attempt to palpate bowel interposed between the vagina and rectum. Again, this is often better demonstrated with the patient standing.
In advanced cases, enterocele with complete loss of fascial attachments will herniate through the vaginal orifice. Rarely will the diagnosis be so obvious. The majority of patients will have a lesser degree of enterocele, remaining a hidden diagnosis contributing to, rather than solely responsible for, a litany of complaints generally focused around pelvic discomfort, sensation of prolapse, and the act of defecation. Even in cases where the diagnosis is clearly evident, it is important to fully evaluate the pelvic floor for synchronous pathology. This allows one to address all surgical aspects of pelvic floor dysfunction during a single intervention, while, at the same time, increasing the probability of a successful outcome .
Imagin g
The vast majority of enteroceles are not detected on physical exam and require designated imaging to detect their presence [11]. Dynamic imaging of the pelvic floor is the key component to identify and address all aspects of pelvic floor pathology. Traditionally, this has been obtained with X-ray defecography studies. More recently, magnetic resonance imaging (MRI) defecography is supplanting classic defecography. Some suggest this is due less to improved images and detection, but more to reluctance on the part of both patient and radiologist to pursue classic defecography. We, however, believe that dynamic MRI with rectal contrast (MRI defecography) provides superior anatomic and physiologic detail of all three compartments in both static and functional states. The limitation of MRI defecography stems from the inability to truly document the patient’s anatomy during the act of defecation—as we are generally instructing patients to “push as if you are passing stool,” rather than having them defecate out contrast material as with a flouroscopic defecography study.
Evacuation proctography was initially limited to a fluoroscopic technique. This requires the patient’s rectum to be filled by a thick, radiopaque paste via rectal tube, followed by defecation while undergoing fluoroscopic imaging seated on a radiolucent commode (Fig. 12.3). This often produces consternation on the patient’s part, in addition to significant radiation exposure. It does provide excellent images and a true physiologic evaluation of defecation. It is important that the small bowel has also been opacified with oral contrast prior to imaging to enhance identification of the small intestine.
Fig. 12.3
X-ray defacography . (a) Resting. The patient has an incidental rectocele. (b) Patient initiates bear-down, collapsing the rectum. (c) Enterocele forming as patient continues to bear-down. (d) Enterocele deepens as intra-abdominal pressure increases
The advent of MRI defecography allows for excellent images of all three compartments and obviates the need for additional studies if the bladder, uterus, or other pelvic organs require imaging. Patients find the procedure much more agreeable, as they do not need to actually defecate during the process. In addition, they are spared exposure to ionizing radiation. MRI in the seated position is best suited for this exam, but it is not readily available at many institutions. Regardless, we have been very satisfied with images obtained with standard, supine MRI. The addition of an evacuation phase, rather than simple instruction to bear down, is considered mandatory by some [12]. Gousse et al. compared physical examination, MRI, and intraoperative findings and found the sensitivity, specificity, and positive predictive value of MRI in identifying enterocele to be 87%, 80%, and 91%, respectively [13]. In a systematic review of dynamic MRI imaging for pelvic organ prolapse, Broikhuis et al. confirmed that dynamic MRI proves useful within the subset of identifying the presence of enteroceles as a component of pelvic floor prolapse [14]. For those interested, we highly recommend an excellent review of dynamic MRI, available online by searching: Dynamic MR Imaging of the Pelvic Floor: a Pictorial Review [15] (Table 12.1).
Table 12.1
Grading of enterocele as visualized by evacuation proctography
Grade |
1. Enterocele descending to the upper one third of the vagina |
2. Enterocele descending to the middle one third of the vagina |
3. Enterocele descending to the lower one third of the vagina |
Additional Studies
Obtaining a history consistent with enterocele, a confirmatory physical exam and appropriate dynamic imaging of the pelvis allow us to correctly identify all components of a given patient’s pelvic floor pathology, leading to selection of appropriate interventions. On occasion, certain adjunctive studies are indicated. First and foremost, colonoscop y should be performed to evaluate for significant redundancy of the sigmoid colon or “kinking” of the rectosigmoid junction, which would alter the choice of surgery to include resection of this segment of bowel. Moreover, other possible causes of the patient’s symptoms, such as tumor, stricture, and solitary rectal ulcer, must be ruled out.
In the patient with complaints of constipation, functional studies of the bowel are also indicated. In our practice, we routinely order a SITZMARKS® study (Fig. 12.4) to distinguish whether the cause of constipation is due to colonic inertia or obstructed defecation. A capsule is ingested by the patient, which dissolves in the upper GI tract releasing 24 radiopaque rings. The patient then returns for serial abdominal X-rays on certain days over the following week—we typically obtain films on post-ingestion days three, five and seven. This allows for determination of overall colorectal function and aids in determining if constipation is due to colonic motility (i.e., colonic inertia) or defecatory dysfunction (i.e., obstructed defecation). If greater than 80% of the rings have been evacuated in the one-week evaluation period, the test is considered normal. If the test is abnormal (i.e., five or more markers remain), then we focus on where the markers are located. If all have advanced to and clustered in the rectum, this suggests that the patient’s colonic motility is normal and the constipation is due to obstructed defecation of either functional or anatomic nature (such as rectal prolapse, enterocele, rectocele, descending perineum syndrome, and paradoxical puborectalis contraction/anismus). If the remaining markers are scattered throughout the colon or have not reached the rectum, then this represents colonic inertia and the pathology lies in the motility of the colon and not in a functional/anatomic issue with defecation.
