In one line
Pelvic organ prolapse is failure of the pelvic-floor support system — the levator ani and the endopelvic fascial attachments — that lets a vaginal wall descend; the consultant task is to localise the defect by compartment and POP-Q, match the treatment to the woman's symptoms and goals rather than to the stage on paper, and offer native-tissue repair, pessary or apical suspension within a transvaginal-mesh landscape now restricted to research and to abdominal sacrocolpopexy.
The support anatomy, the POP-Q points and the basic distinction between conservative and surgical care are assumed here — those foundations are at genital prolapse. What follows is the level above: choosing between competing operations, defending the route and the use of mesh from the trial data, and managing the woman whose prolapse coexists with incontinence, who has failed a previous repair, or who is too frail for reconstruction.
Mechanism & pathophysiology
Prolapse is a disorder of support, not of the organ. The bladder behind a cystocele is structurally normal; what has failed is the anterior vaginal wall and its lateral attachments. The suffix "-cele" therefore names the prolapsing vaginal segment, not a herniated viscus — cystocele (anterior wall), rectocele (posterior wall), enterocele (peritoneal sac, usually apical/posterior), and apical descent of uterus or vault. Naming the compartment drives the operation; naming the organ does not.
DeLancey's three levels of vaginal support are the framework that converts an examination finding into a surgical plan:
- Level I — apical suspension. The cardinal–uterosacral ligament complex suspends the cervix and upper vagina to the sacrum and lateral pelvic sidewall. Level I failure produces uterine or vault prolapse and is the level most often under-treated: an anterior repair that ignores a detached apex fails, because much of what looks like a "cystocele" is apical descent dragging the anterior wall down with it.
- Level II — lateral attachment. The mid-vagina is attached laterally to the arcus tendineus fascia pelvis (the "white line") and to the levator ani. Level II failure gives the classic anterior (cystocele) and posterior (rectocele) wall prolapse, either as a midline fascial break or a paravaginal (lateral) detachment.
- Level III — distal fusion. The distal vagina and urethra are fused to the perineal body, perineal membrane and levator. Level III failure underlies a deficient perineum, gaping introitus and distal anterior-wall descent, and is where obstetric perineal trauma writes itself into later prolapse.
Two tissue systems fail together. The levator ani — principally the puborectalis/pubococcygeus — provides the active, constant tonic floor that keeps the urogenital hiatus closed and takes the load off the ligaments; the endopelvic connective tissue (the cardinal and uterosacral ligaments, the pubocervical and rectovaginal fascia) provides the passive suspensory backup. The boat-and-mooring analogy holds: the levator is the water level holding the boat up, the ligaments are the ropes that only take strain when the water drops. Levator avulsion — detachment of the puborectalis from its pubic insertion, the commonest major obstetric levator injury, seen in roughly 15–30% of women after a first vaginal birth and far more after forceps — drops the "water level", enlarges the hiatus, transfers chronic load onto the ligaments, and is the single strongest anatomical predictor of prolapse and of recurrence after repair. This is why a repair in a woman with bilateral avulsion is biomechanically swimming upstream.
The risk-factor list maps onto these mechanisms rather than sitting beside them: vaginal parity and instrumental/operative vaginal delivery (levator and fascial injury), age and oestrogen withdrawal (collagen quality and quantity fall, the connective tissue weakens), chronically raised intra-abdominal pressure (obesity, chronic cough, constipation and straining, heavy lifting), connective-tissue disorders (Ehlers–Danlos, Marfan), and previous prolapse or hysterectomy (the apex is now unsupported). A genetic/collagen contribution is real — prolapse clusters in families and presents in nulliparous women — which is why the operation alone never fully "cures" the underlying tissue tendency.
The same biomechanics explain why repairs recur. A native-tissue colporrhaphy re-approximates attenuated fascia; it does not regenerate strong collagen or reattach an avulsed levator. So the woman with a wide hiatus and a dropped "water level" is asking a plicated, already-weak tissue layer to hold a load the muscle should be carrying — and over time it stretches again. Two corollaries follow for the consultant: first, the apex is load-bearing, so a repair that restores the anterior or posterior wall but leaves a descended apex unsupported simply transfers the strain back onto the weakest segment and fails; second, a durable apical operation works at a different anatomical level — sacrocolpopexy re-suspends the vault to the sacrum with a permanent bridge, sidestepping the reliance on the woman's own attenuated ligaments, which is precisely why it outlasts native-tissue suspension in the long-term data.
Assessment
The history establishes whether the anatomy is actually the problem. A POP-Q stage II that the woman cannot feel needs no operation; a stage II at the introitus that dominates her life may. Separate the symptoms by system because each maps to a compartment and to a different repair:
- Bulge symptoms — "something coming down", a visible/palpable lump, vaginal pressure or dragging that worsens through the day and on standing and eases on lying. The bulge symptom (seeing or feeling the prolapse) is the one most reliably cured by surgery; vague pelvic discomfort is not.
- Voiding/urinary — incomplete emptying, hesitancy, a weak or positional stream, the need to splint (push the bulge back to void) or digitate. Occult stress incontinence matters disproportionately: a large anterior or apical prolapse can kink the urethra and mask stress leakage that surgery then unmasks — reduce the prolapse on examination and re-test for stress leakage before operating, and counsel accordingly.
- Defecatory — incomplete evacuation, the need to splint the perineum or posterior wall, post-defecatory soiling; these point to a posterior-compartment/rectocele or perineal problem and frequently to constipation that must be treated before and after any repair.
- Sexual — dyspareunia, awareness of laxity, body-image distress, or simple avoidance; ask directly, because sexual outcome is a primary reason to choose (or avoid) a particular operation and is routinely neglected.
On examination, inspect at rest and on Valsalva, in the dorsal position and, if findings do not match the symptoms, standing — the prolapse a woman complains of may only appear when she is upright at the end of the day. A Sims (single-bladed) speculum retracts one wall so the opposite compartment can be graded in isolation; you cannot stage an anterior wall while a bivalve speculum is holding it up. Assess each compartment separately, look specifically for the apex (reduce the anterior and posterior walls and ask the cervix/vault to descend — apical support is the most missed defect), test the levator (ask for a voluntary contraction; feel for, and grade, avulsion and the resting hiatal size), and do a stress test with the prolapse reduced.
The POP-Q (the standardised system from Bump's 1996 terminology report, adopted by IUGA/ICS) replaces the vague "first/second/third-degree" language with reproducible measurement against a fixed reference, the hymen (0 by definition; points above/inside are negative centimetres, points below/outside are positive). Six vaginal points and three landmarks are recorded, all on maximal Valsalva:
- Aa — anterior wall, 3 cm proximal to the external urethral meatus (range −3 to +3).
- Ba — the most dependent point of the remaining upper anterior wall.
- C — the cervix or vaginal vault (the leading edge of the apex).
- D — the posterior fornix (the level of the uterosacral attachment); omitted after hysterectomy, and a large C–D gap suggests cervical elongation rather than true apical descent.
- Ap — posterior wall, 3 cm proximal to the hymen (−3 to +3).
- Bp — the most dependent point of the remaining upper posterior wall.
- gh (genital hiatus, mid-urethra to posterior midline hymen), pb (perineal body, posterior hymen to mid-anus), tvl (total vaginal length, the only measurement at rest).