Pelvic organ prolapse and urinary incontinence

Overview

Pelvic floor dysfunction gives three main problems: urinary incontinence, pelvic organ prolapse and anal incontinence. About one in four women has at least one of these in her life, and they become much commoner with age. They are rarely dangerous, but they ruin quality of life.

The common thread is damage to the pelvic floor during vaginal childbirth, made worse by ageing, the menopause and anything that raises abdominal pressure.

Applied anatomy of pelvic support

The muscle floor

• Levator ani is the key muscle. It is always slightly contracted and holds the pelvic organs up against abdominal pressure.
• Three parts: puborectalis, pubococcygeus, iliococcygeus.
• The gap for the urethra, vagina and rectum is the urogenital hiatus. If the muscle weakens, the hiatus widens and organs drop through it.

The connective tissue supports (three levels)

Pelvic organ prolapse

Definition and types

Prolapse is descent of one or more pelvic organs into or out of the vagina.

Risk factors

• Vaginal childbirth, especially many births, forceps, long labour, big babies and perineal trauma.
• Age and the menopause (oestrogen loss weakens tissues).
• Raised abdominal pressure: chronic cough, constipation, obesity, heavy lifting.
• Connective tissue disorders.
• Previous hysterectomy (vault prolapse).

Damage happens through stretching of the pudendal nerves and tearing or avulsion of the levator ani (puborectalis) from the pubic bone.

Grading

Traditional degrees (still used in local exams), for uterine descent:

POP-Q stages (measured against the hymen while straining):

Clinical features

• Feeling of a lump or bulge, heaviness or dragging, worse at the end of the day and relieved by lying down.
• Low backache.
• Urinary: frequency, incomplete emptying, difficulty voiding (may need to push the bulge back to pass urine), recurrent UTI; stress leak with a cystocele.
• Bowel: incomplete emptying; may need to press on the vagina or perineum to open the bowels (digitation) with a rectocele.
• Sexual: discomfort, laxity.
• A procidentia exposed outside can become ulcerated (decubitus ulcer) and bleed. In a woman with a uterus who bleeds, still exclude endometrial cancer.

Management

Conservative:

• Supervised pelvic floor muscle training for at least 4 months if the prolapse does not go more than 1 cm beyond the hymen.
• Treat cough and constipation; lose weight.
• Vaginal pessary: ring pessary first (needs an intact perineal body); shelf or Gellhorn pessary if the perineum is deficient. Ideal for the elderly, the medically unfit, women who have not finished their family, or those awaiting surgery. Change about every 6 months and check for ulceration. Rare problems: incarceration, fistula.

Surgical (if conservative treatment fails or the woman prefers it):

• Anterior repair (cystocele) and posterior repair (rectocele), with perineal body repair.
• Vaginal hysterectomy with support of the vault, for uterine prolapse in women who have finished childbearing.
• Uterus-sparing options: sacrospinous fixation or sacrohysteropexy.
• Vault prolapse: vaginal sacrospinous fixation or abdominal sacrocolpopexy (durable).
• Colpocleisis (closing the vagina): for frail women who are not sexually active.
• Transvaginal mesh is now restricted in the UK because of erosion and pain complications.

Urinary incontinence

Normal continence

• The detrusor relaxes during filling; parasympathetic (muscarinic) nerves make it contract to void.
• The urethral sphincter is kept closed by sympathetic (alpha) tone and the pudendal nerve (voluntary).
• Normally a cough pushes pressure equally onto the bladder and the bladder neck, so no leak occurs.

Types

Mixed incontinence = both stress and urge; treat the dominant one first.

Assessment

• History: type, severity, pads used, fluid intake, drug history (diuretics, alpha blockers), red flags (haematuria, pain).
• Examination: abdominal mass (a large fibroid or ovarian cyst can mimic an overactive bladder), palpable bladder, prolapse, atrophy, visible leak on coughing, pelvic floor contraction strength.
• Midstream urine in everyone (exclude infection).
• Bladder diary for 3 days.
• Post-void residual (bladder scan) if voiding symptoms.
• Urodynamics (cystometry): not for everyone; used when conservative treatment fails, symptoms are mixed or complex, or before surgery (especially after previous surgery). A catheter in the bladder and one in the rectum record pressures; detrusor pressure = bladder pressure − abdominal pressure.
• Cystoscopy: haematuria, suspected fistula, previous pelvic surgery.

Treatment of stress incontinence

1. Lifestyle: weight loss if BMI over 30, fluid advice, less caffeine.
2. Supervised pelvic floor muscle training (PFMT): contractions three times a day for at least 3 months. First-line for stress and mixed incontinence. Biofeedback, electrical stimulation or weighted vaginal cones help women who cannot contract well.
3. Duloxetine (occasional use): increases sphincter tone; nausea is common.
4. Surgery when conservative care fails:
   • Midurethral tape (retropubic TVT or transobturator TOT): cure about 80-85%, lasting 10 years or more. Risks: voiding difficulty, bladder perforation, new urgency, mesh exposure.
   • Burch colposuspension (open, through a Pfannenstiel incision): same cure rate; risk of later posterior vaginal wall prolapse.
   • Autologous fascial sling.
   • Urethral bulking injections: under local anaesthetic, for the frail; lower and shorter-lived benefit.

Treatment of overactive bladder

1. Bladder retraining for at least 6 weeks: hold on for longer and longer intervals; with PFMT.
2. Reduce caffeine, alcohol and fizzy drinks; adjust fluids.
3. Antimuscarinic drugs: oxybutynin, tolterodine, solifenacin, trospium, fesoterodine. They block muscarinic receptors on the detrusor. Side effects: dry mouth, constipation, blurred vision, confusion in the elderly (avoid immediate-release oxybutynin in frail older women). Contraindicated in urinary retention, myasthenia gravis, gut obstruction, severe ulcerative colitis and toxic megacolon.
4. Mirabegron: a beta-3 agonist that relaxes the detrusor during filling.
5. Vaginal oestrogen in postmenopausal women.
6. Second line: botulinum toxin A injected into the detrusor by cystoscopy (risk of voiding difficulty needing self-catheterisation), or sacral neuromodulation.

Genital fistula

• Vesicovaginal fistula (VVF): an abnormal opening between bladder and vagina. Leads to continuous leakage of urine day and night, unlike stress incontinence.
• In developing countries including Pakistan, the commonest cause is prolonged obstructed labour: the fetal head presses the bladder against the pubis, causing pressure necrosis. The leak typically begins in the second week after delivery, when the dead tissue sloughs.
• Other causes: pelvic surgery (e.g. hysterectomy), pelvic radiotherapy and advanced cancer.
• Diagnosis: examination, dye test, cystoscopy.
• Management: continuous bladder drainage (small fistulae may close in a few weeks); larger ones need specialist surgical repair.
• Rectovaginal fistula: commonest cause is also obstetric (third or fourth-degree tears, obstructed labour); the woman passes wind or faeces per vagina.

Anal incontinence (brief)

• Involuntary loss of flatus or faeces.
• Obstetric anal sphincter injury is the commonest cause in young women (risk: forceps, big baby, long second stage, occipitoposterior position).
• Internal sphincter damage: passive soiling; external sphincter damage: urge incontinence.
• Tests: endoanal ultrasound, anal manometry. Treatment: diet, loperamide, pelvic floor exercises and biofeedback, then sphincter repair or sacral nerve stimulation.

Quick revision

• Levator ani = main muscle; cardinal + uterosacral ligaments = main uterine support.
• Childbirth (pudendal stretch, levator avulsion) is the main cause of prolapse and stress leak.
• Second degree: cervix to or through the introitus; third degree: whole uterus out (procidentia).
• Pessary for the frail; repair or vaginal hysterectomy for the fit; colpocleisis if no intercourse.
• Stress leak: pelvic floor training 3 months, then tape or colposuspension (80-85% cure).
• Urge leak: bladder training, antimuscarinics or mirabegron; no surgery.
• Urodynamics before incontinence surgery or when diagnosis is unclear.
• VVF in Pakistan: obstructed labour; continuous leak from the second week.

Written by The House Job from standard references (Gynaecology by Ten Teachers; Obstetrics by Ten Teachers).

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