Pelvic organ prolapse is defined as the descent of one or more of the anterior vaginal wall, posterior vaginal wall, the uterus, or the apex of the vagina (vaginal vault or cuff scar after hysterectomy).1 Anterior vaginal wall prolapse/cystocoele is the descent of the anterior vaginal wall and can be due to central and/or paravaginal fascial defects. Uterine or vaginal vault descent and enterocele are often seen in combination with cystocoele.
It is difficult to identify the true prevalence of symptomatic cystocoele as most of the estimates are based on patients admitted to hospital for surgery. It is estimated that in the general population, prolapse of the anterior wall occurs in 14% to 27% of women and, in combination with other sites, in 33% of cases.2,3 The Women’s Health Initiative showed that in women ages 50 to 75 years, 41% had various degrees of pelvic organ prolapse of which 34% were cystocoeles.4
Anterior vaginal wall prolapse rises in both prevalence and incidence with age. The Women’s Health Initiative revealed that women in the age groups 60 to 69 years and 70 to 79 years had a higher risk of prolapse than the 50- to 59-year age group.4 Regarding new onset of cystocoeles, Handa et al. found that these occurred in 9% of women per year; however, spontaneous regression was common, especially with grade one prolapse.5 In older parous women prolapse is more likely to be progressive than regressive.6
From cadaver studies, DeLancey defined three levels of pelvic support.7 Level I accounts for support of the upper third of the vagina and the cervix. Level II involves the middle third of the vagina and its attachment to the pelvic side walls laterally by fascia extending transversely between the bladder and the rectum attaching to the arcus tendineus fascia pelvis (ATFP) and the superior fascia of the levator ani.7 Loss of level II support results in the formation of cystocoeles and rectocoeles. The lower third of the vagina fuses with the perineal membrane, perineal body, and levator ani and this forms level III.7
Support of the pelvic organs depends on the striated muscle and its nerve supply, as well as fascia and connective tissue. Disruption of any or all of these can lead to pelvic organ prolapse.
Under normal circumstances the pelvic organs are supported by both the pelvic muscles and connective tissue. The levator ani muscle has both slow twitch (type 1) and fast twitch (type 2) fibers with the former providing resting tone and the later preventing stretching of the pelvic ligaments. Women with prolapse more often have defects in the levator ani and generate less vaginal closure force during a maximal contraction when compared to women without prolapse.8 Defects in the levator ani have been seen on magnetic resonance imaging (MRI) in 20% of primiparous patients and are not present in nulliparous patients suggesting childbirth as a causal factor.9
The connective tissue of pelvic floor fascia is composed of elastin, smooth muscle, fibroblasts, blood vessels, and collagen, with collagen being the main component.10 A reduction in the collagen and increased turnover of collagen has been observed in patients with pelvic organ prolapse and urinary incontinence (UI).11-13 The fibromuscular tissue in patients with prolapse shows a loss of smooth muscle at the vaginal apex, increase protease activity, myofibroblast activation, and abnormal smooth muscle phenotype. It is unknown whether these changes are the cause of or as result of the mechanical forces. With age the vaginal tissues are slow to return to a nonstressed state. Therefore, with a rise in parity and lack of estrogen there is less elasticity and recovery of the vaginal tissues after mechanical stress.
The pudendal nerve supplies somatic innervation to the levator ani muscles. Childbearing can result in pelvic floor injury due to the damage of the pudendal nerve by compression or traction within the Alcock canal. A prospective study using electromyography showed that 80% of women had partial pelvic floor denervation following delivery.14 Neurophysiologic studies confirmed that weakness of the pelvic floor muscles was due to partial denervation following vaginal delivery.15 Childbirth can initiate the process while further vaginal deliveries can result in progressive denervation. As a result poor support from the levator ani muscle can occur leading to both pelvic organ prolapse and stress UI.
The pathophysiology of anterior vaginal wall prolapse is complex and often consists of more than one underlying cause. Normal pelvic floor function requires the muscular and fascial components to work together with the neural components to facilitate pelvic organ support. Weakening of these components is likely to result in descent of the pelvic organs resulting in prolapse. Pregnancy, vaginal delivery, age, increased abdominal pressure such as that occurs from chronic cough, straining or obesity, family history/genetic factors, ethnic background, and previous hysterectomy have all been identified as risk factors for anterior prolapse or cystocele.
The role of the biomechanical properties of the vaginal tissue in the pathogenesis of anterior vaginal wall prolapse is poorly understood. In women with weak fascia due to altered connective tissue and reduced collagen, prolapse can result. An example of this is seen in patients with conditions such as Marfan or Ehlers-Danlos syndrome where a higher rate of pelvic organ prolapse has been reported compared with the general population. This supports the hypothesis that weak connective tissue is implicated in the pathogenesis of pelvic organ prolapse.16
As mentioned, vaginal support depends not only on the facial attachments but also on striated muscle and its nerve supply. Disruption of these can lead to pelvic organ prolapse and is nicely demonstrated by the “Dry Dock Theory” (Figure 12-1).17 Wall and DeLancey suggested that one should look at the entire pelvis with the ligaments, pelvic floor muscle, and fascia as the support mechanisms.17 It is suggested that when the pelvic floor muscles function normally, the support mechanisms including the fascia and ligaments that attach the organs to the pelvic side wall represented by “the Ropes attaching to the Dock” are under normal tension. When the pelvic floor muscles are damaged, this is analogous to no water in the dry dock. In this situation, the pelvic organs are now supported solely by the fascia and ligaments and over time these support mechanisms are unable to support the pelvic organs resulting in pelvic organ prolapse.18
FIGURE 12-1
A boat in a dry dock. The ropes attaching the boat to the dock stand for ligaments. In A, the ligaments are aided by pelvic floor muscles (water). In B, the ligaments provide all support.(From Ref.18)
The risk of progression of a cystocoele in patients who are overweight (body mass index 25–29.9 kg/m2) or obese (body mass index >30 kg/m2) has been quoted as 32% and 48%, respectively, when compared to patients with a normal body mass index of <25 kg/m2.19 However, weight loss of 10% was not associated with a significant prolapse regression in this study, suggesting that there is irreversible damage done to the pelvic floor by excessive weight gain.19 This observation stands in contrast to investigations into the effect of weight loss on UI where weight loss has been observed to reduce symptoms.20
Parity is strongly linked to prolapse. In the Oxford Family Planning Association Study,21 women with two births were 8.7 times more likely to undergo a surgery for prolapse than nulliparous women. Twin studies have shown a higher incidence of prolapse in parous twins compared to nulliparous twins thus linking childbirth with prolapse.22 There is also a significant descent of parts of Aa/Ba in nulliparous women relative to the hymen in both the third trimester and postpartum period.23 Therefore, anterior vaginal wall prolapse is associated with both pregnancy and vaginal delivery. Quiroz et al. found that following a single vaginal birth the odds of a woman having pelvic organ prolapse beyond the hymen were almost ten times higher than women who did not have a vaginal birth.24 Tegerstedt et al. showed the odds of mothers developing symptomatic pelvic organ prolapse were 3.3 times higher in mother of four compared to mothers of one.25
Genetic factors may account for up to 30% of the incidence of pelvic organ prolapse but the contribution of underlying genetic differences between individuals is still the least understood risk factor for development of prolapse.26 Genes seem to influence pelvic organ prolapse by influencing the connective tissue structures.27 In families with high incidence of prolapse there may be an autosomal dominant transmission with data suggesting that a polymorphism in the promoter LAMC1 (laminin gamma 1) may increase susceptibility to pelvic organ prolapse at an early age.26 Linkage to chromosome nine has been associated in families with pelvic organ prolapse.28
McLennan et al. showed that 47% of women with pelvic organ prolapse have a family history of prolapse.29 It has estimated that siblings of women with pelvic organ prolapse have a five times increased relative risk of prolapse compared with the general population.30 Chiaffarino et al showed the risk of pelvic organ prolapse was higher in women whose sisters or mothers had pelvic organ prolapse with an odds ratio (OR) of 3.2.31 Genetic susceptibility would seem to depend on both a maternal family history of prolapse and a paternal history of hernias.29 The risk of developing pelvic organ prolapse was 1.5 higher in women with a male relative having a hernia compared to families without such a history. Furthermore, the risk of prolapse was 1.8 times higher in women with a female relative with a prolapse and/or hernia compared to women without a family history of a prolapse and/or hernia.29
Key Points
Similar to other compartments, the most consistent symptoms of anterior prolapse is the feeling of a bulge.
Not all women with prolapse will be symptomatic.
The decision to treat prolapse should be driven by patient symptoms and bother.
The main and most consistent symptom of prolapse is the feeling of a bulge at or beyond the introitus.32 Other symptoms include lower abdominal pressure (63%), pelvic heaviness (56%), pelvic discomfort (58%) visualization of the prolapse (43%), sexual dysfunction, and overactive bladder or voiding dysfunction.33
Assessing the degree of “bother” and effect on the quality of life is important when deciding on the appropriate treatment for the individual patient. Such “patient selection” is key to successful management.
First, it must be confirmed that symptoms are due to pelvic organ prolapse and not due to another cause. For example, vaginal pain is rarely a symptom of prolapse and is unlikely to be helped by surgery. Such women should have further investigations to determine the cause of pain, including neuropathic causes.
Second, there are women in the general population who have pelvic organ prolapse on clinical examination but are asymptomatic.34 It is debatable whether these patients require surgery especially in cases where the prolapse does not protrude beyond the hymen. The decision to operate should be based on the patient’s symptoms as well as the physical examination. Validated symptomatic questionnaires such as International Consultation on Incontinence Questionnaire-Vaginal Symptoms (ICIQ-VS) can be used to assess vaginal and sexual symptoms and quality of life whereas the ICS pelvic organ prolapse quantification (POP-Q) system is recommended for objective physical examination assessment.
The POP-Q examination gives an objective assessment of a patient’s prolapse and is explained in Chapter 4. Decent of prolapse to a level of 0.5 cm beyond the hymen is found to accurately predict the symptoms of bulging; however, there is no threshold that predicts other pelvic floor symptoms.35
It is unclear when the final decision regarding surgical therapy based on the preoperative or intraoperative findings under anesthesia should be made. For example, Fayyad et al. have shown that when examined under anesthesia, in 16% of cases there was a greater or lesser degree of prolapse and 11% had a prolapse in a different compartment.36 This might be due to the relaxation of the pelvic floor secondary to the anesthesia and the traction applied, and might not be representative of the patient’s prolapse in the awake state. This requires further research.
At the preoperative examination the patient should perform a Valsalva maneuver and/or strain in the position where the prolapse is most pronounced, usually the standing position. The standing position is also particularly useful if the symptoms do not correlate with the examination. A Sims speculum is used if the patient is in the lateral position but a finger can be used if the patient is in the standing position. Paravaginal defects might be detected by visualizing the area of detachment of the lateral vagina from its attachment to the ATFP but this has not been validated.37 Preoperative clinical assessments of paravaginal defects only have a positive predictive value of 57% when compared with intraoperative assessments.37 Imaging is probably the only method of precisely identifying defects associated with cystocoele (Figures 12-2 and 12-3).
FIGURE 12-2
Pelvic axial magnetic resonance imaging images of vaginal support level III. The left shows a nulliparous asymptomatic woman with normal vaginal configuration (“Butterfly shape”) with intact pubococcygeal/pubovisceral muscle attachment to the pubic bone in an asymptomatic woman without prolapse. The pubovesical muscle is visible anterior to the urethra. The image on the right shows a patient with a cystocoele with loss of anterior lateral vaginal wall support, with associated right pubococcygeal muscle detachment from the pubic bone, and compensatory hypertrophy of the left pubococcygeal muscle.
FIGURE 12-3
Magnetic resonance imaging appearances of central fascial defect before (Figures A1 and A2) and after (Figures B1 and B2) anterior vaginal repair. The images demonstrate reduction of the “herniated” bladder (Ba) base following anterior repair.(From Ref.38)
Imaging might complement our clinical assessment by identifying what is prolapsing and possibly identify specific defects, which might help target the appropriate surgery.39
The use of MRI can be helpful in determining the site of the anatomical defects (Figures 12-2 and 12-3), is reproducible, and provides a visual record both before and after surgery.38 MRI is noninvasive and can evaluate the pelvic organs in various planes with soft tissue and temporal resolution, and can be especially useful in patients with multicompartment symptoms, severe prolapse, and recurrence after surgery. It has the ability to demonstrate more extensive prolapse than physical examination alone.40 MRI has also been found to be a complementary instrument to identify and even quantify prolapse while dynamic MRI has the added advantage of being able to diagnose paravaginal defects that cannot be assessed using the POP-Q system.40
Used before and after vaginal repair, MRI has shown isolated lateral defects in 33%, central fascial defects in 8%, a combined central and lateral defect in 12%, and no defects in 46% of women. Fifty percent of lateral defects were corrected following anterior repair.38 In this same study, defects in the pubococcygeal and pubovesical muscles were associated with anatomical failure.38
Unlike ultrasound, MRI is expensive and evidence suggests that translabial/perineal and transvaginal ultrasound might be a suitable alternative to MRI.
Ultrasound is an established tool in Urogynecology. The requirements for a two-dimensional (2D) translabial pelvic floor ultrasound include a B-mode capable 2D ultrasound system with a 3.5- to 6-MHz transducer.41 Advances in technology have allowed the use of three-dimensional and four-dimensional transperineal ultrasound allowing imaging in different planes and visualization of axial planes in a similar manner to MRI.42 Three-dimensional ultrasound allows for the imaging planes to be varied thus enhancing the visibility of the anatomical structures. Four-dimensional ultrasound, or dynamic assessment of pelvic organ mobility, can be advantageous in describing prolapse associated with muscular or fascial detachments and defining the functional anatomy.41 Both have a positive relationship between the area of the levator hiatus and the severity of the anterior compartment prolapse. Association between the area of levator hiatus and symptoms has not be determined, and although anatomical correlations are helpful in determining treatment plans, ultimately symptoms must be regarded as the most important factor when determining treatment type. Therefore, ultrasound and MRI, while useful for research purposes, should not be used at the expense of thorough history and clinical examination. MRI and ultrasound studies are more likely to be indicated in cases of failed surgery, recurrent prolapse, or where clinical assessment does not concur with the patient’s systems.
Urodynamics may be indicated when women present with cystocele and are considering surgical intervention. “Occult” or “hidden” incontinence is thought to occur when the urethra is kinked while the anterior vaginal wall descends. Treatment of the vaginal bulge exchanges one symptom—bulging—for another. Occult incontinence has an estimated prevalence of 23% to 62% and is defined as “Stress incontinence only observed after the reduction of coexistent prolapse.”1,43-45 It is a sign not properly defined and the methods of reducing the prolapse to reveal incontinence vary. In some cases a pessary might be used to reduce the prolapse but this can obstruct the urethra thus giving a false-negative result.1 It is suggested that the pessary test has an excellent negative predictive value (98%), high specificity (93%) but poor sensitivity (67%) in predicting postoperative stress UI with reduction of the prolapse in patients with pelvic organ prolapse.46
It is unclear whether “occult incontinence” should be treated “prophylactically.” The Colpopexy and Urinary Reduction Efforts (CARE) study of prophylactic colposuspension performed at the time of sacrocolpopexy in women asymptomatic for UI prior to surgery showed that reduction of the prolapse does not help to identify women at higher risk of developing postoperative stress incontinence. In that study the authors concluded that women who underwent prophylactic colposuspension were less likely to have incontinence symptoms following surgery than those who did not undergo prophylactic colposuspension.47 It is unknown whether this conclusion can be extrapolated to other antiincontinence procedures but currently there is there is no evidence supporting the addition of a prophylactic procedure for vaginal surgery, or whether the results may be extrapolated to the performance of other incontinence procedures such as midurethral slings.47 There is the risk that such “prophylactic” incontinence surgery might result in complications such as voiding difficulty.48 Patients should therefore be advised regarding the potential risk of new-onset UI and, that should it occur, corrective surgery can be performed at a later stage.
It is recommended that where UI can be demonstrated on reducing the prolapse, urodynamics be considered. This might reveal the type of occult incontinence, as well as predicting the effect of prolapse surgery on postoperative voiding.
In patients with preexisting bothersome urodynamic stress incontinence (which has failed to respond to conservative measures such as pelvic floor muscle training [PFMT]), a concomitant anti-incontinence procedure can be undertaken at the time of the prolapse surgery.
The types of nonsurgical treatment for anterior vaginal wall prolapse include pelvic floor/physiotherapy and pessaries (Figure 12-4). Conservative methods focus on decreasing the intra-abdominal pressure such as reduction in heavy lifting and weight loss.49 These measures can be used in conjunction with PFMT and other methods of treatment of anterior vaginal wall prolapse including the use of pessaries.
PFMT is usually offered to patients with a mild prolapse (eg, grade 1–2), in those who have not yet completed their families, and in patients who are unwilling to have surgery or a pessary. It might also be used as a form of secondary prevention to prevent mild symptoms worsening.
Limited evidence from randomized controlled trials support the use of PFMT in the treatment of symptomatic pelvic organ prolapse.50 In one study, women with mild prolapse assigned to the PFMT group were less likely to have worsening prolapse compared with those with severe pelvic organ prolapse; however, by the 24-month follow-up this difference was no longer evident.51 Results of this trial are unclear as the definition and measurement of prolapse was nonstandardized.
Despite the role for surgery, there is still a significant role for the use of pessaries in the nonsurgical treatment of anterior vaginal wall prolapse. Pessaries have been shown to improve symptoms such as vaginal “bulge,” and aid in bladder, bowel, and sexual function.52
Multiple types of pessaries are available and include ring, Gelhorn, ring with support, cube, Hodge, knob incontinence dish with support, donut, and inflatoball. A survey conducted among gynecologists in the United States revealed that the ring pessaries were thought to be most effective and easiest to use for correction of anterior vaginal wall prolapse.53
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