Enterocele: is there a histologic defect?

Enterocele: is there a histologic defect?

Enterocele: Is There a Histologic Defect? Paul K. Tulikangas, MD, Mark D. Walters, MD, Jennifer A. Brainard, MD, and Anne M. Weber, MD, MS OBJECTIVE: ...

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Enterocele: Is There a Histologic Defect? Paul K. Tulikangas, MD, Mark D. Walters, MD, Jennifer A. Brainard, MD, and Anne M. Weber, MD, MS OBJECTIVE: To examine the histology of the vaginal wall in women with an enterocele confirmed by physical examination, cystoproctography, and intraoperative exploration. METHODS: Thirteen women with posthysterectomy apical and posterior wall prolapse were evaluated with a detailed physical examination, cystoproctography, and intraoperative exploration. All women had enterocele repair. A specimen of full thickness vaginal wall from the leading edge of the enterocele was excised and examined histologically. The histology of these patients was compared with the histology of two comparison groups, five women undergoing hysterectomy without prolapse and 13 women undergoing radical hysterectomy. RESULTS: One woman with an enterocele repaired intraoperatively did not have an enterocele by cystoproctography. One woman with an enterocele repaired intraoperatively did not have an enterocele detected by physical examination. All women with an enterocele repaired had an intact vaginal wall muscularis. No woman had vaginal wall epithelium in direct contact with the peritoneum. The average vaginal wall muscularis thickness in women with enteroceles was 3.5 ⴞ 1.4 mm, in women with no prolapse 3.2 ⴞ 0.8 mm, and in women undergoing radical hysterectomy 2.8 ⴞ 0.9 mm. CONCLUSION: Women with enteroceles have a welldefined vaginal muscularis between the peritoneum and vaginal epithelium. (Obstet Gynecol 2001;98:634 –7. © 2001 by the American College of Obstetricians and Gynecologists.)

An enterocele is a peritoneum-lined sac herniating through the pelvic floor, most commonly between the rectum and vagina. Women with enteroceles have more severe prolapse than women with pelvic organ prolapse without enterocele.1 Although clinically common, there is still a lack of consensus regarding the pathophysiology of enteroceles. From the Department of Obstetrics and Gynecology and Department of Anatomic Pathology, Cleveland Clinic Foundation, Cleveland, Ohio; and Department of Obstetrics and Gynecology, Magee-Women’s Hospital, Pittsburgh, Pennsylvania. Funding for this study was provided by the Cleveland Clinic Foundation Research Programs Council and the Division of Minimally Invasive Surgery, Grant No. 6476.

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One theory of enterocele formation proposes that there is a defect in the fibromuscular tube of the vagina, which allows the peritoneum to come in contact with the vaginal wall epithelium.2 Another theory states that enteroceles occur because of a loss of support to the vagina or because of a change in the vaginal axis.3 Understanding the etiology of enterocele is important because appropriate treatment can then be directed at the underlying problem. If there is a defect in the vaginal wall muscularis, surgical repair should include repairing this segment of the vaginal wall. If the problem lies in support of the vagina, correcting this should be the goal of surgery. The purpose of this study was to identify the histologic characteristics of the vaginal wall in women with proven enteroceles. We hope that by understanding these findings, we will be able to identify and better treat this problem.

MATERIALS AND METHODS This study was approved by the Institutional Review Board and funded by the Research Programs Council at the Cleveland Clinic Foundation. Women with posthysterectomy apical vaginal wall prolapse to the hymen, who were scheduled to undergo surgery by the vaginal route from September 1999 to August 2000, were eligible for this study. Participants had a detailed standardized preoperative physical examination to grade severity of pelvic organ prolapse and to detect enterocele.4 This examination included inspection for peristaltic motion in the prolapsed segments, palpation for bowel in the prolapsed vaginal segments, and a supine rectovaginal examination. If an enterocele was not detected with these maneuvers, a standing rectovaginal examination was performed. Patients routinely underwent preoperative cystoproctography according to the technique described by Kelvin et al.5 Enterocele was defined radiologically as the small bowel below the pubococcygeal line in any stage of cystoproctography. Intraoperatively, all prolapsed vaginal segments were assessed for the presence of an enterocele. Initially, the

VOL. 98, NO. 4, OCTOBER 2001 © 2001 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc.

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posterior vaginal wall or the vaginal apex was incised vertically. When the enterocele was identified, the peritoneum was entered through a small window, and a finger was placed in the cul-de-sac. Taking care not to distort the tissue, a 2 ⫻ 2 cm full thickness section of the leading edge of the enterocele was excised. All surgical repairs were carried out in the routine fashion. We used the vaginal wall from two groups of women as comparisons. The first group of specimens was from five women without pelvic organ prolapse who were undergoing hysterectomy for other indications. These women were examined preoperatively to confirm the absence of prolapse. The vaginal wall at the cul-de-sac adjacent to the posterior edge of the cervix was excised from these specimens. The second comparison group was patients who underwent radical hysterectomy for invasive cervical cancer. Thirteen tissue blocks of full thickness vaginal wall were obtained from our pathology department. These patients were not examined preoperatively by the study authors. All vaginal wall specimens were fixed in 10% neutral buffered formalin. They were embedded in paraffin, sectioned, and stained with Movat’s pentachrome stain.6 The specimens were embedded on edge to allow a full thickness section from the vaginal epithelium to the peritoneum. In two sections from the comparison group without prolapse on physical examination, the vaginal wall epithelium was not visualized, but there was a well-organized muscularis. Slides were examined for the presence or absence of vaginal wall muscularis. If an organized layer of vaginal wall muscularis was present, its thickness was measured. An analysis of variance was done comparing the average vaginal wall thickness of the three groups. Multiple comparisons were performed with a Bonferroni correction to detect pairwise differences. RESULTS Fifteen women underwent surgery, had an enterocele identified and surgically treated. Two of the subjects were excluded: one because her surgery was changed to an abdominal sacral colpopexy and no tissue was excised, and one because the vaginal wall tissue was dissected when identifying the enterocele. Thirteen women make up the study population. Demographic characteristics of the subjects are shown in Table 1. Twelve of 13 women had an enterocele identified by cystoproctography (Figure 1). The woman who did not have an enterocele on cystoproctography but did have one identified intraoperatively had adhesions of omentum to the peritoneum in the posterior cul-de-sac. One

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Table 1. Demographic Characteristics of the Study Population (n ⫽ 13) Age (mean years ⫾ SD) Body mass index (mean kg/m2 ⫾ SD) Prior prolapse or incontinence surgery Menopausal status Premenopausal Postmenopausal with HRT Postmenopausal without HRT Parity (mean ⫾ SD) Stage of pelvic organ prolapse4 Stage 0 and I Stage II Stage III and IV

66 ⫾ 11 27 ⫾ 4 10 (77%) 2 (15%) 8 (62%) 3 (23%) 3.7 ⫾ 1.2 0 1 (8%) 12 (92%)

SD ⫽ standard deviation; HRT ⫽ hormone replacement therapy.

woman with an enterocele identified intraoperatively did not have an enterocele identified by preoperative physical examination. Table 2 shows the average vaginal wall thickness in the study and comparison groups. No women in this study had vaginal wall epithelium in direct contact with peritoneum. An analysis of variance comparing the three groups showed no statistically significant difference among the three means (P ⫽ .32). Multiple comparisons found no pairwise differences. Figure 2 shows an example of the vaginal wall in a patient with an enterocele. Figure 3 shows an example of the vaginal wall in a woman with no pelvic organ prolapse. DISCUSSION We have demonstrated that the vaginal wall of enteroceles has an intact muscularis similar to control patients.

Figure 1. Cystoproctography demonstrating an enterocele (vaginal prolapse containing small bowel). Tulikangas. Enterocele Histology. Obstet Gynecol 2001.

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Table 2. Vaginal Wall Muscularis Thickness in Women With Enteroceles and Controls Women with enteroceles (n ⫽ 13)

Control group 1* (n ⫽ 5)

Control group 2† (n ⫽ 13)

3.5 ⫾ 1.4

3.2 ⫾ 0.8

2.8 ⫾ 0.9

Vaginal wall muscularis thickness (mm)

Data presented as mean ⫾ standard deviation. * Women without prolapse undergoing hysterectomy. † Women undergoing radical hysterectomy.

Recently, some pelvic surgeons have proposed a definition of enterocele in which there is a “defect” in the fibromuscular tube of the vagina.2 By that theory, the vaginal wall epithelium comes in contact with the peritoneum. We did not find this in any of our patients, even those with large enteroceles identified by physical exam-

ination, cystoproctography, and repaired intraoperatively. In women without prolapse undergoing hysterectomy, a small piece of the vaginal wall was excised over the cul-de-sac. Sometimes it was difficult to measure the vaginal wall muscularis in these specimens because of

Figure 2. Vaginal wall with Movat stain of patient with an enterocele (A: vaginal wall epithelium, B: vaginal wall muscularis, C: peritoneum).

Figure 3. Vaginal wall with Movat stain of patient with no pelvic organ prolapse (A: vaginal wall epithelium, B: vaginal wall muscularis, C: peritoneum).

Tulikangas. Enterocele Histology. Obstet Gynecol 2001.

Tulikangas. Enterocele Histology. Obstet Gynecol 2001.

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limited amounts of tissue. In the second comparison group, we measured the vaginal wall muscularis in radical hysterectomy specimens. Unfortunately, we were not able to examine radical hysterectomy patients preoperatively for the presence or absence of prolapse. Both comparison groups showed an organized vaginal wall muscularis similar to the study patients. Perhaps the reason we were able to identify vaginal wall muscularis is that we used a Movat pentachrome stain.6 In standard hematoxylin and eosin stained sections, the muscular wall of the vagina may be difficult to differentiate from the submucosal fibrous connective tissue. We found the Movat stain helpful as it highlights collagen, elastin, and muscle by staining them different colors. In some patients with enteroceles and pelvic organ prolapse, the vaginal wall muscularis was thicker than in the normal controls. In these cases, the vaginal wall muscularis is intact but must support the abdominal contents within the prolapsed segment. Perhaps in this setting, the smooth muscle of the vaginal wall hypertrophies, much like smooth muscle in the arterial walls of a patient with hypertension. A weakness of this study is the small number of patients. There may be women with enteroceles with attenuated or absent vaginal wall muscularis. Occasionally on physical examination, we have thought the vaginal wall was very thin in women with enteroceles. Certainly, women in whom peristalsis of the bowel is noted through the vaginal wall must have a thin muscularis. Good surgical outcomes have been reported by excising the apparent defect in the apex of the vaginal wall and resuspending the apex to the uterosacral ligaments.7 It is not clear whether surgical success should be attributed to “repairing the enterocele defect” or to resupporting the apex of the vagina to the uterosacral ligaments. The pathophysiology of enterocele is complex and poorly understood. Definitions and etiologies have been proposed using clinical, radiologic, and histologic criteria, all without conclusive supportive data. Normal vaginal support is provided by the connection between the fibromuscular tube of the vagina and its surrounding web of endopelvic fascia. We believe that in most enteroceles, the vagina has an intact epithelium and fibromuscular tube but has lost a portion of its connection to the web of endopelvic fasia. With enteroceles, this deficient

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vaginal support is usually at the vaginal apex or upper rectovaginal space. This definition is similar to the “traction” enterocele as defined by Nichols and Randall in which an enterocele is fundamentally a vaginal support abnormality.3 A second type of enterocele occurs in association with defects in the vaginal support, a wide levator hiatus, and increased intra-abdominal pressure. Zacharin has called this a “pulsion” enterocele.8 These are less common and were not seen in this series. All patients in our study with surgically identified enteroceles had a well-developed vaginal wall muscularis with no focal “defect.” For patients such as these, surgical repair should be directed toward supporting the prolapsed vaginal segments and restoring the normal vaginal axis. REFERENCES 1. Chou Q, Piedmont M, Weber AM. Clinical presentation of patients with enteroceles. Obstet Gynecol 2000;96: 599 – 603. 2. Richardson AC. The anatomic defects in rectocele and enterocele. J Pelvic Surg 1995;1:214 –21. 3. Nichols DH, Randall CL. Vaginal surgery. 4th ed. Baltimore: Williams and Wilkins, 1996:336 –50. 4. Bump RC, Mattison A, Bo K, Brubaker LP, DeLancey JO, Klarskov P, et al. The standardization of terminology of female pelvic organ prolapse and pelvic organ dysfunction. Am J Obstet Gynecol 1996;175:10 –7. 5. Kelvin FM, Maglinte DDT, Benson JTB. Evacuation proctography (defecography): An aid to the investigation of pelvic floor disorders. Obstet Gynecol 1994;83:307–14. 6. Russell K. A modification of Movat’s pentachrome stain. Arch Path 1972;94:187–91. 7. Miklos JR, Kholi N, Lucente V, Saye WB. Site-specific fascial defects in the diagnosis and surgical management of enterocele. Am J Obstet Gynecol 1998;179:1418 –23. 8. Zacharin RF. Pulsion enterocele: Review of functional anatomy of the pelvic floor. Obstet Gynecol 1980;55:135– 40. Address reprint requests to: Mark D. Walters, MD, Head, Section of Urogynecology and Pelvic Reconstructive Surgery, Department of Obstetrics and Gynecology/A81, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195; E-mail: [email protected]. Received March 8, 2001. Received in revised form June 8, 2001. Accepted June 21, 2001.

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