Pathophysiology

The pelvic organs are mainly supported by the levator ani muscles and the endopelvic fascia (a connective tissue network connecting the organs to the pelvic muscles and bones). Genitourinary prolapse occurs when this support structure is weakened through direct muscle trauma, neuropathic injury, disruption or stretching. A multifactorial cause for this damage is likely. The orientation and shape of the bones of the pelvis have also been implicated in the pathogenesis of genitourinary prolapse.

Confirmed risk factors

• Increasing age (risk doubles with each decade of life).^[1]
• Vaginal delivery.
• Increasing parity.^[2][3]
• Overweight (BMI 25-30) and obesity (BMI >30).
• Spina bifida and spina bifida occulta.

Possible risk factors

• Intrapartum variables (controversial and unproven):^[4][5]
  • Fetal macrosomia.
  • Prolonged second stage of labour.
  • Episiotomy.
  • Anal sphincter injury.
  • Epidural anaesthesia.
  • Use of forceps.
  • Use of oxytocin.
  • Age <25 years at first delivery.
• Race.
• Family history of prolapse.
• Constipation.
• Connective tissue disorders, eg Marfan's syndrome, Ehlers-Danlos syndrome.
• Previous hysterectomy.
• Menopause: a recent small study found no association between oestrogen status and prolapse.^[6]
• Selective oestrogen-receptor modulators.^[7][8]
• Occupations involving heavy lifting.

Epidemiology

• The incidence of genital prolapse is difficult to determine as many women do not seek medical advice.^[9]
• It is thought that some loss of uterovaginal support is present in most adult women.^[5] However, there is no consensus about what level of loss of uterovaginal support is 'normal' and what is abnormal.
• In the Women's Health Initiative Study, 41% of women aged 50-79 showed some degree of pelvic organ prolapse. 34% had a cystocele, 19% a rectocele and 14% uterine prolapse.^[3]
• Prolapse is the most common reason for hysterectomy in women aged over 50 and accounts for 13% of hysterectomies in women of all ages. In the UK, genital prolapse accounts for 20% of women on the waiting list for major gynaecological surgery.^[9]
• Hispanic and Asian women had increased risk of cystocele and African-American women a reduced risk when compared with white women in one study.^[3]

Types of genitourinary prolapse

Prolapse can occur in the anterior, middle, or posterior compartment of the pelvis:^[9]

Anterior compartment prolapse

• Urethrocele: prolapse of the urethra into the vagina. Frequently associated with urinary stress incontinence; other symptoms are infrequent.
• Cystocele: prolapse of the bladder into the vagina. An isolated cystocele rarely causes incontinence and usually leads to few or no symptoms. However a large cystocele may cause increased urinary frequency, frequent urinary infections and produce a pressure sensation or mass at the introitus.
• Cystourethrocele: prolapse of both urethra and bladder.

Middle compartment prolapse

• Uterine prolapse: descent of the uterus into the vagina.
• Vaginal vault prolapse: descent of the vaginal vault post-hysterectomy. Often associated with cystocele, rectocele, and enterocele. With complete inversion, the urethra, bladder, and distal ureters may be included resulting in varying degrees of retention and distal ureteric obstruction.
• Enterocele: herniation of the pouch of Douglas (including small intestine/omentum) into the vagina. Small enteroceles are usually asymptomatic. Can occur following pelvic surgery. The neck of the hernial sac is usually sufficiently wide to make strangulation very rare. Can be difficult to differentiate clinically from rectocele but a cough impulse can be felt in enterocele on combined rectal and vaginal examination.

Posterior compartment prolapse

• Rectocele: prolapse of the rectum into the vagina.

Cystourethrocele is the most common type of prolapse, followed by uterine prolapse and then rectocele. Urethroceles are rare.^[9]

Classification of genitourinary prolapse

The degree of uterine descent can also be graded as:

• 1st degree: cervix visible when the perineum is depressed - prolapse is contained within the vagina.
• 2nd degree: cervix prolapsed through the introitus with the fundus remaining in the pelvis.
• 3rd degree: procidentia (complete prolapse) - entire uterus is outside the introitus.

Symptoms

• Mild genital prolapse may be asymptomatic and an incidental finding. However, in other women, symptoms can severely affect their quality of life.
• Symptoms are related to the site and type of prolapse.
• Vaginal/general symptoms can be common to all types of prolapse.

Vaginal/general symptoms

• Sensation of pressure, fullness or heaviness.
• Sensation of a bulge/protrusion or 'something coming down'.
• Seeing or feeling a bulge/protrusion.
• Difficulty retaining tampons.
• Spotting (in the presence of ulceration of the prolapse).

Urinary symptoms

• Incontinence.
• Frequency.
• Urgency.
• Feeling of incomplete bladder emptying.
• Weak or prolonged urinary stream.
• The need to reduce the prolapse manually before voiding.
• The need to change position to start or complete voiding.

Coital difficulty

• Dyspareunia.
• Loss of vaginal sensation.
• Vaginal flatus.

Bowel symptoms

• Constipation/straining.
• Urgency of stool.
• Incontinence of flatus or stool.
• Incomplete evacuation.
• The need to apply digital pressure to the perineum or posterior vaginal wall to enable defecation (splinting).
• Digital evacuation necessary in order to pass a stool.

Examination

• Thorough history taking is needed to determine the patient's main symptoms and the effect of these on their daily life. Ask about coital difficulty.
• Examine the patient in both a standing and left lateral position if possible.
• Use a Sims' speculum inserted along the posterior vaginal wall to assess the anterior wall and vaginal vault and vice versa. Ask the patient to strain.
• Uterine descent can be assessed by gentle traction with a vulsellum.
• A bivalve speculum can also be used to identify the cervix or vaginal vault. Ask the patient to strain, and slowly remove the speculum. Look for the degree of descent of the vaginal apex.
• Determine the parts of the vagina (anterior, posterior or apical) that the prolapse affects. Determine the degree of prolapse.
• Ulceration and hypertrophy of the cervix or vaginal mucosa with concomitant bleeding may be seen in women with prolapse that protrudes beyond the hymen.
• A rectal examination can be helpful if there are bowel symptoms.

Investigations

• Diagnosis is usually clinical and based on history and examination.
• If there are urinary symptoms consider the following:
  • Urinalysis ± a mid-stream specimen of urine (MSU).
  • Post-void residual urine volume testing using a catheter or bladder ultrasound scan.
  • Urodynamic investigations.
  • Urea and creatinine.
  • Renal ultrasound scan.
• If there are bowel symptoms consider the following:
  • Anal manometry.
  • Defecography.
  • Endo-anal ultrasound scan (to look for an anal sphincter defect if faecal incontinence is present).

Management

• Most are of the opinion that no treatment is necessary if incidental asymptomatic mild prolapse is found. However, there is no evidence or consensus of opinion about whether or how to treat these women.^[4]
• The current management options for women with symptomatic genitourinary prolapse are:
  • Watchful waiting
  • Vaginal pessary insertion
  • Surgery
• However, the risks of surgery for some, even for advanced prolapse, may not be warranted.

Watchful waiting

• If a women reports little in the way of symptoms this is probably appropriate.
• Careful observation for the development of new symptoms is needed.
• Treatment may be needed if obstructed defecation or urination, hydronephrosis or vaginal erosions develop.
• A number of conservative treatment options have also been suggested:
  • Lifestyle modification: including treatment of cough, smoking cessation, constipation and overweight and obesity. However, even though the association of prolapse with these lifestyle factors has been demonstrated, the role of lifestyle modification as a prevention or treatment of prolapse has not been investigated.^[5]
  • Pelvic floor muscle exercises: a recent Cochrane review concluded that there is no definite evidence for the benefit of pelvic floor muscle exercises in the management of uterine prolapse and that further trials are needed.^[12] The pelvic organ prolapse physiotherapy study is currently underway in worldwide centres. It may be beneficial as primary therapy for early stages of uterine prolapse.^[4] Pelvic floor exercises may be more successful under the supervision of a physiotherapist.
  • Vaginal oestrogen creams: some advocate a trial of topical oestrogen cream for 4-6 weeks if prolapse is mild but there is no current evidence of any benefit.

Vaginal pessary insertion

• A good alternative to surgery.
• Inserted into the vagina to reduce the prolapse, provide support and relieve pressure on the bladder and bowel.
• Made of silicone or plastic. A ring pessary is usually the first choice.
• Although not supported by definite evidence, current opinion is that pessaries are effective:
  • For short-term relief of prolapse prior to surgery.
  • In the long term if surgery is not wanted or is contra-indicated.^[13]
• A 2004 Cochrane review found no randomised trials of pessary use in women with prolapse.^[14] A randomised trial looking at the use of vaginal pessaries and pelvic floor exercises in prolapse is currently underway.
• Fitting a pessary:^[4]
  • Ensure the patient's bladder and bowel are empty
  • Perform a bimanual examination and use the forefinger to estimate the size of the vagina.
  • The aim is to fit the largest pessary that does not cause discomfort.
  • The pessary fits well if a finger can be swept between the pessary and the walls of the vagina.
  • Ask the patient to walk around, bend and micturate to ensure that the pessary is retained.
• How often to follow up: there is no clear consensus about how often to follow up women who have had a pessary fitted. After 3 months and then every 6 months, if there are no complications, has been suggested.^[15]
• At each follow-up: ask about new symptoms. Examine the vagina for irritation and erosions. Change the pessary. If erosions are seen, remove the pessary and apply oestrogen cream. If the erosion does not heal, arrange biopsy.
• Complications: vaginal discharge and odour, vesicovaginal and rectovaginal fistulas, faecal impaction, hydronephrosis, urosepsis. These tend to occur in women who are not regularly followed up.

Surgery

• Surgery is very effective but a combination of procedures may be required and reoperation is required in 29% of cases. The time interval reduces between each successive operation.^[9]
• Indications for surgery are: failure of pessary, patient who wants definitive treatment, prolapse combined with urinary or faecal incontinence.
• Urinary incontinence may be masked by prolapse and can be precipitated by surgery.
• Some operations, eg colposuspension for a cystourethrocele, may predispose to a prolapse in another compartment.
• The choice of procedure will depend on whether the woman is sexually active, the fitness of the patient and surgeon's preference.
• If the prolapse remains corrected and the patient conceives, an elective Caesarean section may be advisable.^[9]
• Generally women should avoid heavy lifting after surgery and avoid sexual intercourse for 6-8 weeks.^[9]

Surgery for bladder/urethral prolapse

• Anterior colporrhaphy: involves central plication of the fibromuscular layer of the anterior vaginal wall. Mesh reinforcement may also be used. Performed transvaginally. Intraoperative complications are uncommon but haemorrhage, haematoma, and cystotomy may occur.^[9]
• Colposuspension: performed for urethral sphincter incontinence associated with a cystourethrocele. The paravaginal fascia on either side of the bladder neck and the base of the bladder are approximated to the pelvic side wall by sutures placed through the ipsilateral iliopectineal ligament.^[9]

Surgery for uterine prolapse

• Hysterectomy: a vaginal hysterectomy has the advantage that no abdominal incision is needed, thereby reducing pain and hospital stay. This can be combined with anterior or posterior colporrhaphy.
• Open abdominal or laparoscopic sacrohysteropexy: this can be performed if the woman wishes to retain her uterus. The uterus is attached to the anterior longitudinal ligament over the sacrum. Mesh is used to hold the uterus in place.
• Sacrospinous fixation: unilateral or bilateral fixation of the uterus to the sacrospinous ligament. Performed via vaginal route. Lower success rate than sacrohysteropexy. Risk of injury to pudendal nerve and vessels and sciatic nerve.

Surgery for vault prolapse

• Sacrospinous fixation: unilateral or bilateral fixation of the vault to the sacrospinous ligament. Performed via vaginal route. Risk of injury to the pudendal nerve and vessels and sciatic nerve. This may have a higher failure rate but a lower perioperative mortality than sacrocolpopexy.^[16]
• Laparoscopic or open abdominal mesh sacrocolpopexy: a mesh is attached at one end to the longitudinal ligament of the sacrum and at the other to the top of the vagina and for a variable distance down the posterior and/or anterior vaginal walls.^[17]
• Iliococcygeal hitch: the vaginal vault is attached on both sides to the fascia of the iliococcygeus muscle. However, this procedure is not recommended by the Royal College of Obstetricians and Gynaecologists (RCOG) as it does not reduce the incidence of postoperative anterior wall prolapse.^[16]

Surgery for rectocele/enterocele

• Posterior colporrhaphy: involves levator ani muscle plication or by repair of discrete fascial defects. A mesh can be used for additional support. Performed transvaginally. Levator plication may lead to dyspareunia.

Obliterative surgery

• Corrects prolapse by moving the pelvic viscera back into the pelvis and closing off the vaginal canal. Known as colpocleisis.
• Vaginal intercourse is no longer possible.
• Advantages are that it is almost 100% effective in treating prolapse and has a reduced perioperative morbidity.
• Not commonly carried out in Europe.
• Preoperative counselling is essential.

Complications

• Ulceration and infection of organs prolapsed outside the vaginal introitus may occur.
• Urinary tract complications include stress incontinence, chronic retention and overflow incontinence, and recurrent urinary tract infections.
• Bowel dysfunction may occur with a rectocele.

Prognosis

• Left untreated, uterine prolapse will gradually worsen.
• Good prognosis is associated with young age, good physical health and a body mass index within normal limits.
• Poorer prognosis is associated with older age, poor physical heath, respiratory problems (eg asthma or chronic obstructive pulmonary disease), and obesity.

Prevention

Possible preventative measures include (trial evidence lacking for most):

• Good intrapartum care, including avoiding unnecessary instrumental trauma and prolonged labour.
• The role of hormone replacement therapy in preventing prolapse is uncertain.^[9]
• Pelvic floor exercises may prevent prolapse occurring secondary to pelvic floor laxity and are strongly advised after childbirth.
• Smoking cessation will reduce chronic cough.
• Weight loss if overweight or obese.
• Avoidance of heavy lifting occupations.
• Treatment of constipation throughout life.