What is POP

Anatomical aspects

The bottom of the abdominal cavity is closed by the pelvic floor. The pelvic floor consists of a system of muscles and connective tissue and ensures that the urine, stool and a fetus cannot just leave the body. In addition, organs such as the bladder, rectum and uterus remain in place. The anatomical support of the organs of the small pelvis is provided by the musculus levator ani complex as well as by the connective tissue complex in the small pelvis. For example, the uterus is held in place by several ligaments of which the sacro-uterine ligament (from cervix to sacrum) is an important pillar. The position of the vagina (the direction of the vaginal axis) also plays a role in the anatomical support: an almost horizontal position of the vagina acts as a valve when the abdominal pressure is increased. Proper nerve provision is necessary for a properly functioning pelvic floor. Dysruption or dysfunction of one or more components of this pelvic floor complex leads to reduction of support and ultimately to prolapse of pelvic organs.¹

Symptoms

Women who seek helpbecause of POP can have a range of complaints.²The most specific complaint is seeing or feeling a bulge. In addition, complaints can occur with regard to the bladder function: incontinence for urine, frequent micturition, incomplete urination, inability to urinate, position change necessaryto urinate. Complaints with regard to bowel function are: incontinence for flatus, fluid or faeces; pain, digital help needed for evacuation of urine or faeces. Sexual dysfunction can also be a consequence of a POP.

Prevalence

Although POP is one of the most common indications for a gynaecological operation, there are relatively few studies on incidence and prevalence of POP.³ A prevalence of symptomatic POP between 4-12% of all women has been reported for Australia and Sweden.^4,5One of the few population studies shows that about 40% of women have a stage 2 or more prolapse.⁶ The probability that a prolapse causes serious discomfort is much lower (11%). A large US study shows a prevalence of 14.2% in all women, resp 41% for women between 50-79 years of age.⁷

A review of studies in developing countries demonstrates a higher mean prevalence of of POP 19.7% in these countries.⁸As studies have major differences in design, definitions and methods, the value of comparison of results is limited. In a systematic review is stated that the low and lower income countries have almost twice the burden of POP than countries of the higher economy.²⁸ Future POP incidence, prevalence, and natural history studies should include non-white women from LMICs and should combine pelvic examination data with validated patient-reported outcome measures when feasible. Anticipated future service needs differ globally, with a greater demand for POP treatment services in well-resourced settings where aging populations are prevalent.^​37

Clinical assessment

A physical examination is the cornerstone for diagnosing POP and for assessing the type and severity of anatomical abnormalities. The examination is usually done in a lithotomy position; both the abdomen and the pelvis are examined externally and internally. The examination is done at rest and at maximum press (Valsalva); all 3 compartments (anterior, middle and posterior) are assessed separately. Also, the overall muscle strength and coordination of the pelvic floor muscles are assessed.

Examination in standing position can be useful if there is a discrepancy between the complaints of the woman and the findings in the research in lithotomy position.²

The place of urodynamic testing is under debate; so far there is no evidence that preoperative urodynamic investigation improves the outcome of prolapse surgery.

Stages

The severity of a prolapse use can be quantified in 4 stages with the Pelvic Organ Prolapse Quantification (POP-Q) score.⁹ In this POP-Q system 9 anatomical landmarks are measured in centimetres to quantify abnormalities, see fig 1. The POP-Q score succeeded previously used scoring systems, see fig 2. It has a good inter-observer agreement and is also suitable for objectifying changes after surgery.Various radiographic modalities have been proposed to measure the extent of POP like for example Dynamic Magnetic Resonance Imaging (MRI, transperineal ultrasound and 3-4D ultrasound have been used in staging POP, but so far all these techniques do not appear to be superior to clinical assessment of POP.¹⁰

fig 1  POP-Q scoring system                                                                                      fig 2  POP scoring systems

Contributing factors

The development of a prolapse has been determined to be multi-factorial. The factors that contribute to the development of a prolapse can be divided into established risk factors and potential risk factors.

Vaginal childbirth is the factor most frequently associated with prolapse and also advancing age and obesity are established risk factors.²  Childbirth can lead to muscular and neurological damage. Poor levator muscle function might be the first step in a process that ultimately causes failure of the connective tissue supports of the pelvic organs.^1,11 In a substantial minority of women delivering vaginally, the puborectalis muscle is shorn off the pelvic side wall. This avulsion risk is strongly associated with age at first delivery and vaginal operative delivery.³

Potential risk factors for developing a POP are: pregnancy, prolonged second stage of labour, high birthweight child, shape of pelvis, hysterectomy,¹³ family history positive for POP¹⁴, race or ethnic origin, connective tissue disorders and chronic predisposing factors like heavy lifting, constipation and coughing.²⁵

Prevention

Reduction of obstetric risk factors offers the potential to prevent subsequent POP. But until now, there is a lack of evidence in this area. Some researchers have mentioned elective caesarean section as a way to reduce risk of POP. However, until specific selection criteria allow providers to ascertain who would and would not benefit from this intervention, it is unlikely to become an effective strategy for prevention.²Some evidence is available for lifestyle changes like reduction of weight in case of obesity. In an experimental and prospective study there is some indication that strenuous exercise increased POP symptoms and reduced pelvic floor support.³⁵ There is also increasing attention for preventive surgery in case of hysterectomy for non-POP indications.³¹

Conservative treatment

Expectant management

Many women with POP, especially those with minor degrees of prolapse not extending the hymenal remnants, complain of little or no discomfort. In such cases a policy of expectant management is appropriate. Weight reduction and lifestyle adjustment can be useful if relevant.²

Pelvic floor muscle training

Although studies have been published on the effectiveness of pelvic floor muscle training in the treatment of genital prolapse, established scientific evidence on the value of physiotherapy is lacking. The conclusions of published studies suggest a short-term positive effect on the experience of the severity of the complaints without a positive effect on the anatomical abnormality itself. A recent study shows a statistical significant improvement in symptoms, but the difference between the studied groups was not clinically relevant.¹⁵ For the time being, the role of pelvic floor muscle training in patients with a prolapse is mainly beneficial for the treatment of micturition, defecation and sexual complaints.

Pessary treatment

From ancient times mechanical devices have been used to reposition prolapsed organs.Pessaries offer a safe, non-surgical option for the treatment of POP.²⁹ Especially in lower grade POP cases the use of a pessary may result in decreasing the frequency and severity of prolapse symptoms and may avert or delay the need for surgery.^16,17 Pessary use can prevent worsening of the prolapse.¹⁸ A recent study in patients with symptomatic POP has shown that nearly two-thirds of women choose a pessary rather than surgery as initial management.¹⁹ The preference for pessary treatment over surgery appears not to be influenced by differences in POP symptoms like bowel or sexual function.

Complications associated with pessary insertion and use include vaginal discharge, ulcerations, excoriations, bleeding, pain, urinary and/or faecal impaction and pessary expulsion.²⁰  Rarely, pessaries cause major urinary, rectal or genital complications such as fistula, hydronephrosis and urosepsis.² These complications are almost exclusively related to a long period of use or neglected use.²⁶

Although traditionally thought of a treatment only for women deemed unfit for surgery or infirm, pessaries are a viable treatment option for the majority of women in the initial management of POP.

Pessary fitting is achieved through trial and error. Correct fitting relieves patient symptoms, allows the patient to void and defecate, stays in place with activity and causes no discomfort to the patient.²⁷ Not in all women/cases a pessary can be inserted or continued for a longer period. In a prospective study 74% of women with symptomatic POP had a pessary fitted successfully.²¹ Success rates, defined as continued pessary use in women who have a pessary fitted, range from 56 to 89% at 2–3 months^21,22, and 28% at 5 years months after insertion.²³ Risk factors for pessary failure are: previous hysterectomy, increased parity, a short vaginal length and wide vaginal introitus, which can occur after prolapse surgery and hysterectomy.

Pessary treatment can be offered to woman by health care workers with very limited resources, important for remote areas of low-income countries.

Followup visits involve removal and cleaning of the pessary, inspection of the vaginal wall and afterwards replacing the pessary. Intervals between these follow up visits vary widely and studies about the ideal length of such intervals are lacking.^32,33

Vaginal pessaries can be broadly divided into two types: support and space-filling pessaries. As there is no evidence to support the use of a specific type of pessary, choice can be based on experience and costs. It is generally accepted that the ring pessary should be the first choice because of ease of insertion and removal. Folding the pessary reduces its size and allows for easy introduction through the vaginal introitus. Its shape prevents collection of vaginal discharge and women can continue to engage in vaginal intercourse with the pessary in situ. The ring pessary with supportmembrane, is useful in cases of procidentia as the uterus cannot prolapse through the closed ring. If the ring pessary fails, other pessaries can be used. Currently, the pessaries are made of silicone or polyvinyl.

Surgery

Surgical treatment and pessary treatment are both efficacious in reducing the presence and severity of prolapse symtoms.³⁴ Women with symptomatic POP who decline pessary treatment or when such treatment fails, require surgical intervention.The risk for a woman to undergo surgery in her life due to a prolapse is 11-19%.²⁴

Surgical treatment for POP can be categorised into reconstructive and obliterative procedures.

Reconstructive surgery aims to correct the prolapse while maintaining vaginal sexual function and relieving any associated pelvic symptoms.³Surgery is not 100% successful. New or recurrent prolapses will occur in a significant percentage (up to 30-35%) and these can be difficult to repair.²⁴

Options for reconstructive surgical repair of POP can be classified by compartment and can be subdivided into abdominal and vaginal procedures.

For a prolapse of the anterior compartment the most used procedure is a colporrhaphia anterior (or possibly variants), for the posterior compartment a colporrhaphia posterior (or possibly variants). These operations, depending on the anatomical outcome measure used, give a considerable chance of recurrences, which are regularly asymptomatic.

As far as symptomatic prolapse of the middle compartment is concerned, the vaginal hysterectomy, whether or not with shortening and suturing of the sacrouterine ligaments in the vaginal top, has been the preferred treatment for some time. However, there has been increasing interest in uterine-saving surgery in recent years. This is because it is becoming clear that not the uterus itself is the cause of the prolapse but the lack of suspension: especially the suspension system of the uterus was found to be inadequate. Various old and new alternative methods receive more attention, such as the sacrospinal hysteropexy and the (modified) Manchester operation.³⁶

Obliterative surgical procedures may be suitable for women who do not wish to preserve coital function. Colpocleisis corrects POP by moving pelvic viscera back into the pelvis and closing off the vaginal canal partly or totally. This type of surgery is associated with high cure rates (up to 95%), fast recovery times and less complications.^2,3

The rationale for using implants in prolapse surgery is that an implant replaces deficient body's own material, gives reinforcement provided by increasing the support surface and induces new support tissue. Although in the short-term operations with vaginal mesh result in better anatomical and functional outcome, the risk of (long term) complications is the reason that operations with mesh are reserved for women with recurrent prolapse.

References