Aetiology

The aetiology is poorly understood. Predisposing risk factors for the development of prolapse include vaginal childbirth, obesity, previous hysterectomy and age [9,10].

Vaginal birth is probably the principal risk factor, with avulsion injury to the levator ani during childbirth along with pudendal neuropathy and fascial damage the most common causes. There is no evidence that instrumental delivery increases the risk of developing POP [11–13]. Nulliparous women may also develop prolapse and a range of other conditions may contribute to the development of the disease [14]. Of these, age is the most significant contributor, with the incidence of prolapse doubling with every decade of life [5,8].

The genetic predisposition is less clear. There does seem to be an ethnic influence, with lower rates of POP reported in Black and Hispanic women compared with white women [5,15]. Twin studies have also demonstrated a genetic component [16] and a familial association has been clearly identified [17]. Because of the protean nature of collagen diseases, it is more difficult to establish a clear link between collagen disorders and POP.

The influence of body mass index (BMI) is well established, which is of some concern given the 20% rise in obesity in the last 20 years [18]. There is no clear consensus that a prior hysterectomy (unless it was performed for prolapse) is a risk factor for subsequent vault or vaginal prolapse [19]. Conditions associated with chronically increased intra‐abdominal pressure, such as chronic cough and heavy lifting, are also considered to be risk factors [15].

Pelvic anatomy

The bony pelvis provides the architectural framework for the supports of the organs of the pelvis. The organs are supported by the fibres of the paracolpium (direct support) and by the levator plate (indirect support). The fibres of the paracolpium arise from a broad area on the pelvic side wall over the fascia of the piriformis muscle, sacro‐iliac joint and lateral sacrum. They insert into the lateral upper third of the vagina, with some fibres inserting anteriorly and posteriorly. These fibres are condensations of the endopelvic fascia and are composed of perivascular connective tissue and smooth muscle and contain blood vessels, lymphatics and nerves. They run in a predominantly vertical direction and their upper borders are continuous with the cardinal and uterosacral ligaments.

The levator ani comprises the pelvic diaphragm muscles: the pubococcygeus, iliococcygeus, puborectalis and coccygeus muscles. Together they form a thin broad muscle arising anteriorly from the posterior aspect of the pubic bone just lateral to the symphysis pubis and laterally from the white line of the obturator internus muscle fascia and ischial spine. The right and left muscle bellies swing backwards and downwards to fuse together behind the anal canal and anterior to the coccyx to form the levator plate between these two structures. The anal canal, lateral vagina and urethra gain some attachment of the medial margins to the levator ani. The levator plate provides indirect support for the vagina by acting as a platform against which the upper vagina and cervix are compressed during episodes of raised intra‐abdominal pressure. Narrowing of the urogenital hiatus also occurs with rises in intra‐abdominal pressure.

The supports of the vagina are divided into three zones: the upper, middle and the lower. The fibres in the upper are largely vertical in orientation while the fibres supporting the middle section are attached to the side wall. The fibres surrounding the lower third are almost fused with the surrounding structures [20]. This reflects the different embryological origins of the vagina and determines the surgical approach to the repair of each level.

Clinical presentation

The most consistent and specific symptom of POP is a feeling of a bulge in the vagina or a sensation of protrusion of tissue out of the vagina. In more advanced cases the prolapse can be seen and palpated outside the vagina with the patient complaining of a ‘lump’. It is not uncommon for women to be asymptomatic in the early morning and then for the symptoms to develop or worsen throughout the day with activity and be relieved by lying down. While some women may present with a single symptom of prolapse, they typically have a more complex presentation that can include urinary symptoms of incontinence, frequency, nocturia and voiding dysfunction; faecal symptoms of incontinence and obstructed defecation; and sexual dysfunction. While these symptoms present commonly in association with prolapse, they are not usually caused by it and therefore are unlikely to be resolved by the surgery aimed at correcting the POP.

In a large study of women with symptomatic vaginal prolapse, 87% reported urinary frequency and urgency, 73% reported urinary incontinence and 50% had symptoms of voiding dysfunction [21]. As stated above this may be because of shared aetiological factors and may not be a direct causal link.

Bowel symptoms include the sensation of incomplete emptying and the need to manually assist defecation. The latter can include putting digital pressure on the perineum or splinting the posterior wall with the fingers during evacuation. Splinting is a mechanical means of improving defecation. In these cases obstructed defecation may be improved by surgery. Pressure on the perineum obviously has a different mechanism of action and there is no evidence that correction of a posterior wall prolapse in these cases will resolve the symptoms of obstructed defecation.

Sexual dysfunction is a common symptom in women attending a urogynaecology clinic [22]. A high percentage are not sexually active but cite the reason as lack of desire and arousal. Pain and discomfort only affect a small number.

The best way to record symptoms is with a validated quality of life (QOL) instrument. The pelvic floor distress inventories (PFDI‐20, PFIQ‐7) are well studied and validated [23]. The use of validated QOL instruments will help provide a more accurate reflection of the symptoms that bother a patient the most. One such system (e‐PAQ, http://www.epaq.co.uk/) can be administered before the patient sees the doctor in clinic. Not only will this help with understanding what worries the patient most but can also be used for assessment of outcomes.

Evaluation

Patients presenting with a complaint of POP need to have a comprehensive history taken. This should include a full urinary, bowel and sexual history. It is also essential to establish which are the most worrisome symptoms and to clarify which symptoms the patient hopes will be corrected. The use of an objective QOL instrument can be very useful in establishing which symptoms are the most bothersome [24]. Because of a lack of understanding of the longitudinal history of prolapse, counselling about the need for intervention can be extremely difficult.

Because of the high incidence of asymptomatic POP, patients presenting to their practitioner with primary bladder or bowel dysfunction are often then referred on for management of the prolapse due to the mistaken belief that their bladder or bowel symptoms are the result of the prolapse noticed during the routine physical examination. Treatment of the prolapse in isolation will very often lead to disappointment with the outcomes achieved. This is a failure of expectation more than a failure of treatment and is a much‐underestimated problem in the management of POP. Similarly, sexual dysfunction is seldom the result of POP in isolation. Other symptoms misappropriated to POP are backache and pelvic pain syndrome.

All women presenting with symptoms of POP should have a thorough examination. This should begin with palpation of the abdomen before proceeding to the pelvic examination to exclude an abdominal mass or ascites. For the pelvic examination the women should ideally be examined in the dorsal lithotomy position with Valsalva. This has been shown to be as effective as an examination in the standing position [25]. In cases where the symptoms do not correlate with the physical findings it may be worthwhile bringing the patient back for a late afternoon clinic and to perform the examination in the standing position [26]. A Sim’s speculum is used to systematically identify each component of the prolapse. To assess for anterior prolapse the blade is used to retract the posterior wall while inspecting the degree of prolapse of the anterior wall. Conversely, for the posterior wall the blade is used to retract the anterior wall while assessing the degree of prolapse of the posterior wall. During this examination the position of the cervix, or in a post‐hysterectomy patient the vault, is determined. The final part of the assessment is a bimanual pelvic examination. There are a range of methods that have been described to classify prolapse. Of these, the POP‐Q method is the internationally accepted standard. The POP‐Q system is the POP classification system of choice of the International Continence Society (ICS), the American Urogynecologic Society (AUGS) and the Society of Gynecologic Surgeons. It has proven inter‐observer and intra‐observer reliability and is the most commonly cited system in the medical literature (Fig. 55.1). Alternatively, the Baden–Walker Halfway Scoring System, which has five degrees/grades, is another commonly used POP staging system but it lacks accredited reproducibility (Table 55.1). The degree, or grade, of each prolapsed structure is described individually (e.g. grade 1 anterior vaginal wall prolapse or grade 3 uterine prolapse). The grade/degree is defined as the extent of prolapse for each structure noted on examination while the patient is straining. Because there are no clear demarcations among the cut‐off stages, the Baden–Walker system lacks the precision and reproducibility of the POP‐Q system.

There is no need for a routine rectal examination or a barrier test to look for urinary incontinence.