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Surgical treatment of posterior vaginal wall prolapse
One-third to one-half of all surgeries for pelvic organ prolapse involve the posterior vaginal wall. Although rectocele repair has been commonly performed for over a century, the long-term functional and anatomic outcomes and ideal surgical technique have not been determined. This chapter will review the anatomy, pathophysiology, evaluation techniques, and surgical management of posterior vaginal wall prolapse and perineal body defects.
Anatomy and pathophysiology
The histology of the apical portion of the posterior vaginal wall consists of mucosa (which includes the epithelium of the posterior wall and the lamina propria), a superficial and deep muscularis layer, and adventitia. This fibromuscular layer has been named rectovaginal fascia and perirectal fascia, perhaps giving the surgeon an illusion of more sturdy tissue than is actually present. Comparisons of the histology of women with and without vaginal prolapse have shown that the smooth muscle content of the posterior vaginal wall of women with prolapse is disorganized and significantly reduced in comparison to women without prolapse.
Prolapse of the posterior vaginal wall may be secondary to the presence of an enterocele, sigmoidocele, rectocele, or a combination of these entities. A rectocele is an anterior protrusion of the rectal wall to the posterior vaginal wall. The rectovaginal space exists between the vaginal tube and the rectum. This potential space, occupied by areolar tissue, allows the vagina and rectum to function independent of each other. Support of the posterior vaginal wall is provided by a complex interaction of the integrity of the vaginal tube, the connective tissue support, and muscular support of the pelvic floor. divided the connective tissue support of the vagina into three levels. All three levels of support should be evaluated and addressed during surgical management of the posterior vaginal wall.
At level I, the apical portion of the posterior vaginal wall is suspended and supported primarily by the cardinal–uterosacral ligaments. This mesentery-like endopelvic fascia originates at the sacrum and the pelvic sidewalls and inserts onto the posterior cervix and upper vagina. With normal support, the apical posterior wall of the vagina is dorsally directed to lie upon the rectum in a horizontal fashion overlying the levator ani muscles. With increases in abdominal pressure, the vaginal tube is closed top to bottom and supported by the pelvic floor muscles.
Level II includes the support for the middle half of the vagina. This support is provided by the endopelvic fascia attaching the lateral posterior vaginal wall to the aponeurosis of the levator ani on the pelvic sidewall. Most of the fibers of the endopelvic fascia connect the lateral edge of the vaginal tube to the pelvic sidewall. Very few of the fibers actually run like a sheet from sidewall to sidewall. The sidewall attachment of the apical half of the posterior vaginal wall is convergent with the anterior vaginal wall at the arcus tendineus fasciae pelvis (ATFP), giving the vagina a flat profile. The distal sidewall attachment of the posterior vaginal wall, the arcus tendineus fasciae rectovaginalis (ATFR), deviates dorsally from the anterior vaginal wall, giving the vagina an “H” appearance at the introitus ( Fig. 20.1 ).
The role of the perineal body is to resist forces directed caudally by the rectum and to provide a physical barrier between the vagina and rectum. The perineal body is thicker (approximately 3 cm in length) and more defined in women than in men. It includes interlacing muscle fibers of the bulbospongiosus, transverse perinei, and external anal sphincter. reconstructed the perineal body into three distinct regions (superficial, mid, and deep) with three-dimensional analysis of thin-slice magnetic resonance imaging (MRI). The superficial region of the perineal body is at the level of the vestibular bulb. The bulbospongiosus muscle inserts into the lateral margins of the perineal body, whereas caudally the transverse perinei muscle and external anal sphincter comprise the bulk of the superficial component. The perineal body extends cranially in the posterior wall of the vagina to approximately 2 to 3 cm proximal to the hymenal ring. The puborectalis loops around the rectum and lateral vagina but does not send fibers to the perineal body. Laterally, the perineal body is attached to the ischiopubic rami through the superficial transverse perinei muscles and the perineal membrane. The perineal membrane spans the anterior half of the pelvic outlet and is comprised of dense fibromuscular tissue. This dense, fused level of support represents level III. Interruption in the support of the perineal body allows the posterior vaginal wall, the perineal body, and the distal portion of the anterior rectal wall to descend with increased rectal pressure (allowing for perineal body hypermobility).
The pelvic floor muscles, of which the levator ani are a major contributor, provide substantial support of the pelvic organs. In a woman with an intact pelvic floor, the puborectalis and remaining levator ani muscles maintain constant tone. This contraction closes the vaginal canal, and the anterior and posterior vaginal walls are in direct apposition. With defecation, the increased pressure placed on the posterior vaginal wall is equilibrated by the opposing anterior vaginal wall, and there is minimal stress placed on the endopelvic fascial attachments ( Fig. 20.2 A). The puborectalis also provides a sling of support for the vaginal tube. This sling leads to an angulation of the midposterior wall of approximately 45 degrees from vertical. The proximal portion of the vagina lies upon (and is supported by) the pubococcygeus and iliococcygeus muscles. The puborectalis helps to close the potential space of the vagina and close the levator hiatus. With a healthy pelvic floor, little stress or strain is placed on the connective tissue support system.
The levator hiatus has been shown to be larger in women with prolapse than in women with normal pelvic support. If there is muscular and/or neurologic damage to the puborectalis, the levator hiatus widens, and the vaginal canal opens. The increased rectal pressure and distension associated with defecation place strain on the endopelvic fascial attachments and the fibromuscularis of the posterior vaginal wall and can result in rectocele and perineal descent ( Fig. 20.2 B and C).
A description and understanding of normal anatomy guides us in identifying areas of loss of support and challenges us to return the vagina to its “normal position” during prolapse surgery. However, static anatomy does not give us insight into the complexities of the pathophysiology of posterior vaginal wall prolapse. compared MR images at rest and maximal Valsalva between women with predominant rectocele and those without prolapse (controls). As the women with posterior vaginal wall prolapse strained, all 10 experienced descent of the apical two-thirds of posterior vaginal wall, resulting in a folding—“kneeling fashion”—that obstructed the rectum in the process. A proportion (but not all) of the women with a rectocele also had widening of the genital hiatus and descent of the distal posterior wall and perineal body. Therefore, identifying and repairing apical posterior wall support is critical to restoring normal anatomy.
A dynamic and complex interplay of the bony pelvis and connective tissue support with the tonically and actively contracted pelvic floor muscles allow the vagina to maintain its anatomic position. Disruption of support leading to herniation of the vagina and surrounding organs (pelvic organ prolapse) can impact urinary, defecatory, and sexual function. Prolapse is most likely attributed to an accumulation of injuries. Risk factors for the development of prolapse may begin at conception and continue to accrue until death. Table 20.1 shows various risk factors for development of posterior vaginal wall prolapse. performed a meta-analysis of the family history of prolapse and concluded that there is strong evidence that women with at least one family member with pelvic organ prolapse have a significantly higher risk of developing prolapse than those without a family history of prolapse. In families with many members affected by pelvic organ prolapse, chromosomal linkage analysis has identified an area on the long arm of chromosome 9 (9q21) that is associated with the development of prolapse. This area of chromosome 9 houses genes involved with the development of connective tissue and muscle in the pelvic floor. It is apparent that abnormalities of connective tissue development (e.g., Ehlers–Danlos syndrome and Marfan syndrome) are related to early development of pelvic organ prolapse. Women with less pronounced connective tissue disorders often have hyperextensible skin and joints. Women with joint hypermobility are more likely to have defecatory evacuation disorders and develop a rectocele.
Table 20.1
Risk Factors for the Development of Posterior Vaginal Wall Prolapse
| Inheritable | Trauma | Promotional |
|---|---|---|
| Genetic | Vaginal delivery | Aging |
| Pelvic surgery | Defecatory dysfunction/chronic straining | |
| Hysterectomy | Obesity | |
| Hormonal | ||
| Smoking | ||
| Chronic disease |
Vaginal delivery, particularly in the occiput-posterior position, is associated with an increased risk for posterior vaginal wall and perineal body trauma and is one of the greatest risk factors for pelvic organ prolapse development. The greatest risk is caused by the first vaginal delivery, with subsequent deliveries likely increasing the risk. MR images in the postpartum period show changes in intensity within the levator ani muscle. These changes likely reflect the recovery process following neurologic or muscular damage related to childbirth. Additionally, aging may impact the levator ani muscles, leading to muscle atrophy and devascularization. Vaginal delivery, age, and size of the genital hiatus (>2 cm often associated with levator injury) have been associated with the development and progression of prolapse in parous women.
Chronic strain and constipation are often found in women with rectocele, perineal descent, and fecal incontinence. It is suggested that, with chronic straining, there is a stretch placed on the pudendal nerve and the nerve to the levator ani muscle; this stretch is amplified in the setting of rectocele and perineal body descent. found that fecal incontinence was more prevalent in women with a rectocele that extended beyond the hymen (31%) than in women with less severe prolapse (19%). Increasing body mass index has been strongly associated with incident rectocele, but not with prolapse of other areas of the vagina (anterior or apical vaginal wall).
Pelvic surgery can predispose a woman to develop prolapse. Alterations of the connective tissue support and injury to the innervation and vascularization to the pelvic floor muscles can occur with pelvic surgery. However, the indication for the pelvic surgery contributes to the risk of subsequent prolapse surgery. In a large case–control study, found that the primary risk factor for development of prolapse after hysterectomy was the degree of prolapse before the hysterectomy. The risk of subsequent prolapse repair in a woman with prolapse to the hymen at the time of hysterectomy was eight times that in women without prolapse, regardless of the route of surgery. The performance of a hysterectomy outside of the setting of prolapse also is a risk for prolapse development. retrospectively evaluated women who presented with primary prolapse. When matched for age and parity, women who underwent a prior hysterectomy were more likely to present with stage 2 or greater posterior vaginal wall prolapse as compared with women without prior hysterectomy (46.5% vs. 25.3%, respectively; P = .01). Additionally, surgical procedures in the pelvis may alter the axis of the vagina, increasing the forces placed on the connective tissue supports. Overelevation of the anterior vaginal wall, as with anterior vaginal mesh or retropubic urethropexy, alters the distribution of force on the vaginal walls and can open the posterior wall to the development of an enterocele and/or rectocele.
Evaluation
History
Many women with a rectocele or a perineal body defect are asymptomatic or unaware of the loss of support. However, most women electing to undergo surgical management of a rectocele report a sense of bulging and/or symptoms relating to sexual, defecatory, or urinary function.
Women with prolapse often describe bulging of the vagina and pressure (particularly if the prolapse extends beyond the hymen), which worsens by the end of the day and improves when lying down. Sexual function is multifaceted in women. Sexual dysfunction may occur in the setting of prolapse through discomfort, loss of sensation, alteration in body image, or incontinence. Vulvovaginal atrophy from lack of estrogen can exacerbate this problem. Women with a perineal body defect, which leads to a widened genital hiatus, may describe loss of sensation for her and her partner during intercourse. If stool is trapped in the rectocele, intercourse may lead to fecal incontinence or instill the fear of fecal incontinence, leading to the avoidance of sex.
Defecatory dysfunction is common in women with a symptomatic rectocele. Women with a large rectocele may trap stool within this rectal pocket, leading to feeling of incomplete emptying, which can result in soiling. Splinting, or placing manual pressure in the vagina or rectum or on the perineum to reduce the prolapse and facilitate emptying of the rectum, is commonly described. prospectively evaluated 160 women undergoing rectocele repair; 87% had bowel symptoms preoperatively. The most common symptom was incomplete evacuation (85%), followed by straining (74%), sensation of obstructed defecation (66%), anal incontinence (63%), and manual splinting (56%). In most studies splinting is the symptom most reliably associated with posterior vaginal prolapse. Defecatory dysfunction of various types is common in women with and without posterior wall prolapse and may be resolved by increasing fiber and water in a woman’s diet. It also may be impacted by a multitude of medical factors and medication use (see Table 20.2 ).
Table 20.2
Medical Factors Impacting Defecatory Function
| Systemic Illness | Mechanical Bowel Obstruction | Medications (Common Culprits) | Psychiatric Conditions |
|---|---|---|---|
| Diabetes mellitus | Hirschsprung disease | Aluminum antacids | Abuse (psychologic, physical, and sexual) |
| Metabolic disorders | Malignancy | Anticholinergics | Eating disorders |
| Thyroid disorders | Inflammatory bowel disease | Antidepressants | Pelvic pain |
| Neuromuscular disorders | Rectal intussusception | Antiinflammatory medications | |
| Autonomic neuropathy | Pelvic organ prolapse | β blockers | |
| Calcium channel blockers | |||
| Iron sulfate | |||
| Opiates |
Infrequent defecation, diarrhea, and irritable bowel are not likely related to a rectocele and may require additional evaluation. Further, appropriate screening for colorectal cancer should be followed. Anal incontinence to some degree is commonly seen in patients with posterior wall and perineal body defects. Many women are reluctant to initiate the conversation about anal incontinence, because of embarrassment, so it is crucial to ask about accidental loss of solid or liquid stool.
An important part of the history to obtain from your patient is an understanding of what her management desires are. If the patient requires and is willing to undergo surgical management, having her verbally express her expectations of surgery can be illuminating.
Physical examination
The patient is typically examined in the dorsal lithotomy or semirecumbent position. There is excellent correlation in the evaluation of prolapse between the supine and standing positions in women performing maximal Valsalva maneuver. If the prolapse observed in the lithotomy position does not recreate the degree of prolapse that the patient described, a standing examination should be performed. However, it is physically more difficult to perform measurements of the prolapse in this position.
To stage the severity of prolapse, the posterior vaginal wall is visualized with the posterior blade of a bivalve speculum or a Sims speculum. The retractor elevates the anterior wall and reduces any uterine or apical prolapse. The patient is asked to increase abdominal pressure with a Valsalva maneuver or cough. The Pelvic Organ Prolapse Quantification (POPQ) system is a standardized, validated tool for measuring and staging pelvic organ prolapse and is described in detail in Chapter 8 . Measurements of the posterior vaginal wall are documented at maximal strain, 3 cm proximal to the hymen (Ap), at the most dependent portion of the posterior vaginal wall proximal to this mark (Bp), and at the vaginal cuff (C) or cul-de-sac, if the uterus is present (D). The genital hiatus (gh) and perineal body (pb) are measured with the patient straining. Evaluation for and staging of concurrent anterior wall and apical prolapse should be performed.
A rectovaginal examination can facilitate evaluation of the support and descent of the perineal body, as well as evaluate the protrusion of the anterior rectum into the posterior vaginal wall. Palpation of loops of small bowel or sigmoid colon in the rectovaginal space with straining confirms an enterocele or sigmoidocele, respectively. Performing a rectovaginal examination in the standing position may increase the detection of an enterocele by allowing the bowel to enter the rectovaginal space. Pressure on the posterior wall of the vagina, directed downward toward the rectum, may facilitate identification of rectal prolapse or intussusception. If you suspect rectal prolapse, allowing a woman to Valsalva in privacy with a handheld mirror to guide her may allow you to see what she is describing.
The perineal body should be evaluated for length (POPQ measurement of pb), strength (including anal sphincter), and descent. It may be difficult to measure perineal descent, but documentation of its presence or absence can be helpful in planning your surgery. Descent of the perineal body occurs with a lack of continuity of the suspensory support at the apex (level I) to the perineal body (level III). It may occur also because of a mass effect of the rectum or small bowel herniating into the perineal body, a perineocele. Perineal descent has been associated with fecal incontinence, possibly related to concurrent damage to the integrity of or stretch and damage to the innervation of the anal sphincter.
Because anal incontinence commonly coexists with rectocele, assessment of the anal sphincter should be performed. This includes evaluation of anal tone, squeeze, and symmetry. If a symptomatic woman is found (or suspected) to have a disrupted anal sphincter on examination, further testing is indicated (see Chapter 27 ).
A focused neurologic examination includes evaluation of sensation, motor function, and reflexes of sacral nerves 2 to 4. The patient is asked to discriminate between sharp and dull on the perineum. Pelvic floor muscle strength can be assessed by asking the patient to contract and relax the pelvic floor muscles around the examiner’s fingers. Reflex testing includes the bulbocavernosus reflex and anal wink.
Diagnostic tests
A woman with defecatory dysfunction and rectocele may benefit from further testing. Defecography provides a two-dimensional view of the efficiency of rectal emptying and quantification of rectal parameters. Evaluation includes rest, squeeze, strain, and evacuation. Contrast in the small and large bowel may also reveal the presence of an enterocele, sigmoidocele, or perineocele. Rectocele, enterocele, and rectal intussusception can be graded based on anatomic evaluation obtained with defecography ( Table 20.3 ). Rectal intussusception, perineal descent, and spastic pelvic floor (pelvic floor dyssynergia) may be apparent during strain. The dynamic nature of the study allows for insight into the defecation process. Retention of more than 10% of the barium following defecation is referred to as barium trapping. It should be recognized that this examination is done in an artificial environment, which may make the patient more prone to incomplete emptying.
Table 20.3
Grading of Posterior Wall Prolapse by Defecography
| Grade 1 | Grade 2 | Grade 3 | |
|---|---|---|---|
| Rectocele | <2 cm | 2–4 cm | >4 cm |
| Enterocele | Proximal third of vagina | Middle third of vagina | Distal third of vagina |
| Intussusception | Above puborectalis | At puborectalis | In anal canal |
Defecation occurs through the coordination of relaxation of the levator ani and external anal sphincter and contraction of the colon. If the puborectalis and/or external anal sphincter is paradoxically contracted during defecation, defecatory dysfunction with straining and incomplete emptying may result. A balloon expulsion test and manometry can indirectly measure the function of the pelvic floor muscles. A woman with a normally functioning pelvic floor should easily be able to expel a 60-mL balloon. Failure to expel the balloon suggests a functional abnormality. Physical therapy with biofeedback can promote coordinated defecation. Resolution of paroxysmal contraction of the pelvic floor muscles before any surgery is imperative to address the woman’s symptoms and to decrease the strain that would be placed on the surgically repaired posterior vaginal wall.
Rectoceles that retain contrast tend to be larger than those that do not. However, fluoroscopic evidence of barium trapping does not relate to patient symptoms. In a symptomatic elderly population, found no association between the abnormalities demonstrated by defecography and symptoms. Defecography performed following surgical management of posterior wall prolapse generally has shown reduction in the size of the rectocele and improvement in emptying. The limitations of defecography include the requirement for special equipment, radiation exposure of the patient, inability to show the rectum and adjacent soft tissue structures simultaneously, and that it is uncomfortable and poorly accepted by patients.
Dynamic MRI provides high-quality images of the pelvic soft tissues and viscera (see Chapter 13 ). It is noninvasive and does not require ionizing radiation or significant patient preparation. However, there is poor correlation between MR grading of prolapse and clinical staging. Because of limited availability of open MR imaging facilities, most facilities perform dynamic MR imaging in the dorsal supine position with a woman’s legs together. Images are obtained at rest, while performing a Valsalva maneuver, and with evacuation. However, during a Valsalva maneuver in this position, the true extent of the prolapse may not be exhibited and may not simulate that woman’s ability to defecate. The limitations of this method of imaging include a lack of standardization of grading of prolapse, high cost, and limited availability of open MRI.
Translabial, perineal, and three-dimensional endoanal ultrasound have been used to evaluate the pelvic organs at rest, with contraction, and with Valsalva (see Chapter 13 ). Ultrasound compares favorably to defecography in identification of rectocele, enterocele, paroxysmal contraction of puborectalis, and rectal intussusception. An endoanal ultrasound provides anatomic detail of the integrity of the external and internal anal sphincters. The advantages of a dynamic ultrasound evaluation of the pelvic floor are avoidance of ionizing radiation, decreased expense, real-time visualization of dynamic maneuvers, and avoidance of asking a woman to defecate in public.
At this time there is a lack of a standardized method of establishing a radiologic diagnosis of a rectocele. Clinical examination has good sensitivity for the detection of a rectocele; therefore radiologic confirmation of the presence or absence of a rectocele is not worthwhile. Although defecatory dysfunction is common in women with prolapse, the extent of the prolapse does not necessarily correlate with the extent of bowel symptoms. If the woman’s primary complaint is defecatory dysfunction or fecal incontinence, rather than a bulge and/or splinting, surgical correction of a rectocele or perineal body defect may not correct her symptoms. evaluated bowel symptoms before and 12 months after rectocele repair and found that, although defecatory dysfunction improved in all categories (incomplete evacuation, straining, sensation of obstructed defecation, anal incontinence, and manual splinting), nearly one-half of women continued to have some defecatory complaint after surgery.
Thus, ancillary testing is pursued based on the woman’s complaints. Validated functional and quality-of-life questionnaires are available and may be administered preoperatively and postoperatively to provide a standardized method of evaluating the surgical outcomes. The patient’s preoperative symptoms and surgical goals will guide the provider in selecting additional testing. A woman who describes lifelong infrequent bowel movements (less than one per week) and an absence of a daily urge to defecate is unlikely to be cured of her constipation with a rectocele repair. A colon transit study may be helpful in identifying patients with slow-transit constipation. Dietary modifications including fiber and laxatives should be encouraged in any woman whose main complaint is constipation (see Chapter 28 ).
Urodynamic testing with prolapse reduction may be useful in women with stage III or stage IV posterior wall prolapse. With retraction of the posterior wall prolapse (simulating correction of the prolapse), women may “develop” stress incontinence or have an increase in leak volumes. If occult stress urinary incontinence is uncovered, then this observation should be factored into preoperative surgical recommendations and planning.
Surgical repair techniques
The decision to undergo surgical repair of pelvic organ prolapse is influenced by the stage and degree of bother from the prolapse, satisfaction with nonsurgical options, and various surgeon- and patient-specific factors. The social context in which a patient lives can greatly impact her decision to pursue surgery. Typically, severity of prolapse symptoms, medical comorbidities, and socioeconomic status play a role in the physician’s and patient’s treatment plan. The decision to perform an isolated posterior repair versus a concurrent posterior repair at the time of other prolapse surgery is influenced by all of the aforementioned factors, but also has some nuances that are important to consider. First, is the patient bothered primarily by bulge symptoms, or does she also have outlet defecation symptoms that need to be addressed? Second, it is important to assess whether or not she is sexually active, and consideration needs to be given to approaching the repair in such a way that sexual functioning will not be affected. The risks and benefits of performing the procedure must be carefully weighed, and the decision to proceed should be shared between the patient and her surgeon.
Current repair techniques address connective tissue defects. A dysfunctional levator ani, which usually widens the levator hiatus, increases the stress and strain on the connective tissues. This is likely a key contributor to the development of pelvic organ prolapse in general. Currently, pelvic floor muscle exercises (with or without biofeedback) are our primary method of strengthening the remaining innervated pelvic floor muscles, but this approach does not address denervated or damaged muscle.
The goals of rectocele repair are to provide anatomic correction, relieve prolapse symptoms, and restore normal bowel and sexual function without creating new symptoms. Understanding the patient’s goals for surgical correction and providing realistic expectations of outcomes are essential components of preoperative management and counseling. Evaluation of prolapsed posterior vaginal wall in the office and then in the operating room should include careful inspection for an enterocele or sigmoidocele and for associated apical support defects.
It is difficult to compare various techniques for repair of posterior vaginal wall prolapse and anterior rectal wall prolapse, because the indications for surgery, exact surgical steps, and standardized definitions of bowel function symptoms usually are incompletely reported. The definitions of anatomic or functional cure also vary from study to study. There are few appropriately powered, prospective randomized studies comparing surgical procedures to correct posterior wall prolapse.
The gynecologist typically approaches repair of a rectocele through a transvaginal incision. The patient is placed in the dorsal lithotomy position with her legs in high leg holders. The colorectal surgeon usually performs an endoanal repair of the rectocele with the patient in the prone position. Patients are given appropriate perioperative prophylactic antibiotics and antiembolic prophylaxis. Mechanical bowel preparation is optional.
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