Pelvic Organ Prolapse

Etiology

DeLancey demonstrated that normal pelvic support is provided by the interaction between the levator ani muscle group and connective tissue attachments that stabilize the vagina at varying levels. Any weakness or tears within the connective tissue leads to the varying pathology of pelvic floor defects.[3] With normal pelvic support, the vagina lies horizontally on top of the levator and muscles. Damage causes the levator ani muscles to become more vertical in orientation, opening the vagina and thus shifting support to the connective tissue attachments.[4] Through biomechanical modeling, it was postulated that the second stage of labor causes the levator ani muscles to stretch more than 200% beyond the threshold for injury.[5] 

Pelvic organ prolapse (POP) is a common condition that is multifactorial in etiology.[6] Combinations of anatomical, physiological, genetic, lifestyle, and reproductive factors contribute to pelvic floor dysfunction throughout a woman’s lifespan. Many studies have correlated parity with a high incidence of POP.[7]

Epidemiology

The incidence of pelvic organ prolapse is highly associated with increased age.[8] Many women with symptomatic POP suffer physical and emotional distress, leading to a negative impact on a woman’s social, physical, and psychological well-being. Although the exact prevalence of pelvic organ prolapse is unknown, an analysis of hospital procedure codes reveals that approximately 200,000 surgeries for POP treatment are performed annually in the United States.[9] Although about 41% to 50% of women present with POP on physical examination, only about 3% are symptomatic.[10] The incidence of pelvic organ prolapse is projected to increase by 46%, to 4.9 million, by 2050.[11]

History and Physical

The majority of patients who present with pelvic organ prolapse do not report symptoms. Patients that do present with symptoms, however, often describe a sense or feeling of a bulge protruding through the vaginal opening. During yearly well-woman visits, screening women for urinary and bulge symptoms that a woman often is embarrassed to bring up during her annual visit is essential.[12] 

A physical examination is essential to diagnose and subcategorize the type of prolapse. Exam findings vary depending on the bladder and rectum's fullness. Women who present with procidentia (prolapse of all 3 compartments) can complain of vaginal discharge secondary to vaginal chafing or epithelial erosion. Patients with POP have a high rate of coexisting pelvic floor disorders. 40% present with urinary incontinence, 37% present with overactive bladder, and 50% present with fecal incontinence.[13] Patients should be routinely screened for alternative pathologies. In many cases, prolapse can mask a hidden stress urinary incontinence.[14] 

Due to urethral kinking or urethral pressure, bladder outlet obstruction can occur. Pelvic organ prolapse may negatively affect sexual activity, body image, and quality of life. Clinicians should always remember to screen for POP, as many patients won't openly admit to symptoms out of embarrassment. A systematic pelvic examination is required to characterize the type and extent of prolapse fully. Begin by asking the patient to perform the Valsalva maneuver and inspect the perineal body, vaginal opening, and screen for apical prolapse. Next, a speculum is inserted to visualize the vaginal apex better. Using a 1-blade sims speculum, the anterior and posterior vaginal walls can be inspected to assess for the presence of cystocele and rectocele, respectively. The Baden-Walker grading system or the pelvic organ prolapse quantification system can quantify the degree of prolapse and aid in clinical assessment.[15]

Evaluation

When considering the diagnosis of POP, assessment for infection, hematuria, and incomplete bladder emptying are necessary. A urodynamic evaluation is recommended to assess bladder and sphincteric function if the patient has significant voiding symptoms.[16] 

Detrusor dysfunction with high post-void residual is a common problem in patients with severe prolapse. Reducing the prolapse during the urodynamic evaluation helps to properly assess sphincteric function and unmask stress urinary incontinence by unkinking the urethra, commonly associated with severe prolapse that would have been otherwise missed. Imaging of the kidney and the ureter by computed tomography (CT) urogram is indicated in women with severe procidentia as the pelvic anatomy, especially the right ureter, might be distorted by the descent of the bladder, pulling down on the ureters, causing obstruction and hydronephrosis.[17]

Treatment / Management

Both conservative and surgical management may be appropriate depending on the patient's age, desire for future fertility and coital function, symptoms severity, and concomitant medical problems. The compartment of descent additionally dictates treatment. Goals of management include symptomatic relief, maintenance or improvement of sexual function, prevention of new support defects and incontinence, and restoration of adequate pelvic support.[18]

Observation and close follow-up are appropriate in women with mild, asymptomatic cases. Most women do not experience symptoms until the bulge protrudes past the vaginal opening. Pelvic floor muscle training exercise (Kegel exercises) allows a systematic contraction of the levator ani muscles, strengthening the pelvic floor. Kegel exercises have been proven to improve symptoms of stress, urge, and mixed incontinence and can be useful in women with mild POP.[19](A1)

Two-thirds of patients with symptomatic POP choose management with a pessary, and up to 77% continue use after 1 year.[20] Pessaries are devices, often made of medical-grade silicone, that are positioned in the vagina to restore normal pelvic anatomy. They are an option for all stages of prolapse and are useful to prevent the progression of prolapse and can delay the need for surgery. 85% of patients are successfully fit for a pessary.[21] However, patients with short vaginal length, wide vaginal opening, or a history of hysterectomy can often have a fitting failure. Often, the initial pessary of choice is a ring pessary that is folded in half for insertion and fits between the pubic symphysis and posterior vaginal fornix. A successful pessary fit remains more than 1 fingerbreadth above the introitus when the patient bears down. After fitting, the patient should sit, walk, and void to ensure comfort and urinary retention. Patients should be instructed that removal and cleaning are necessary nightly, weekly, biweekly, or monthly. 

When considering surgical intervention for pelvic organ prolapse, patient goals for future fertility goals and expectations must be considered and discussed. A variety of procedures, both abdominal and vaginal, are performed in an attempt to restore the pelvic floor function and relieve symptoms. The procedure with an anatomic success rate of 98% and a subjective success rate of 93% is an obliterative procedure known as colpoclesis in which the vaginal cuff is shortened.[22] However, before performing this reconstructive procedure, it is imperative to counsel the patient that coital function is no longer feasible. For patients who wish to maintain coital function, various reconstructive surgeries can be considered.

Adequate support of the vaginal apex has been recognized as an essential component of an adequate surgical repair for advanced prolapse. While some approaches focus on women's native tissues and ligaments for suspension, many incorporate biological grafts or mesh. The advantages of transvaginal approaches include shorter operative and recovery times, whereas the advantages of abdominal approaches provide more durable outcomes and decrease the risk of recurrence.[23](A1)

One of the most widely performed transvaginal suspension procedures is the sacrospinous fixation, in which the coccygeus sacrospinous ligament is attached to the vaginal apex. Advantages include avoiding the morbidity of an abdominal incision, achieving a functional vagina, and the ability to repair coexisting anterior and posterior compartment defects using a single surgical site.[24]  However, because the technique displaces the vaginal axis posteriorly, it can often lead to the development of new anterior compartment defects.[25] Associated complications that have been reported include intraoperative hemorrhage due to laceration of the pudendal artery, vaginal shortening, sexual dysfunction, and injury to the pudendal nerve.[26](B3)

The iliococcygeus suspension is another transvaginal approach with an excellent success rate of apical support. This transvaginal procedure attaches the vaginal apex to the fascia of the iliococcygeus muscle.[27] Since the vaginal axis is unaffected, an anterior compartment prolapse is very rare. Vaginal shortening is a major complication since the ischial spines are inferior to the normal position of the vaginal apex. The uterosacral suspension is an alternative transvaginal approach in which the plication of the uterosacral ligaments across the midline is performed and attached to the vaginal cuff. A disadvantage to consider in this approach is the proximity of the uterosacral ligaments to the ureters.[23](A1)

In recent years, the procedure of choice has become the abdominal sacrocolpopexy, which either laparotomy, laparoscopy, or robotic-assisted can do. Since Lane's initial delineation of the procedure in 1962, the procedure has undergone many modifications. Birnbaum has advocated anchoring the suspensory mesh to the sacrum. However, there is a high risk of hemorrhage from laceration of the presacral vessels.[28] Varying suspensory materials have been used, including mesh, non-absorbable suture, fascia, and dura mater. It is generally believed now that abdominal sacrocolpopexy with mesh provides long-term relief of pelvic prolapse symptoms and restores vaginal function.[29] This procedure should be considered as the primary approach in women who want to retain vaginal function as well as those who have failed previous operations to treat uterine and vaginal vault prolapse.(B3)

Differential Diagnosis

Although pelvic organ prolapse may seem relatively unique in its clinical depiction, there have been instances when POP has been misdiagnosed with alternative pathologies. Considerations when observing bulge symptoms during an office visit include vaginal cysts, cervical polyps, elongation of the cervix, tumors of the urethra or bladder, large urethral diverticulum, and skene gland cysts.

Staging

The American Urogynecologic Society and the Society of Gynecologic Surgeons agreed upon a consensus document for staging pelvic organ prolapse at the 1996 International Continence Society.[30] The resulting pelvic organ prolapse quantification system (POP-Q) has been widely used in clinical practice and research.[31] The technique measures compartment prolapse relative to the anatomic landmark of the hymen. Prolapse points proximal to the hymen are given a negative value, whereas positive values are given to points that protrude past the hymen. 6 points are delineated, including 2 on the anterior vaginal wall (Aa, Ba), 2 on the vaginal apex (C, D), and 2 on the posterior vaginal wall (Ap, Bp). Points Gh, Pb, and TVL describe the genital hiatus, perineal body, and total vaginal length, respectively.[32] Previously used, the Baden-Walker Halfway system is an alternative grading system for pelvic organ prolapse.[15] Normal pelvic support is defined as grade 0. Descent half the distance to the hymen is grade 1, descent to the hymen is grade 2, and descent distal to the hymen is grade 3. Stage 4 describes complete procidentia.

Prognosis

Although bothersome, pelvic organ prolapse has a non-life-threatening prognosis. Most patients are asymptomatic to start. Those that have bulge symptoms have a high rate of regression with pessaries and non-invasive treatments. Surgical intervention has a 95% success rate, and studies analyzing the 2-year and 5-year follow-up and patient satisfaction have shown marked improvement in bulge symptoms and minimal new morbidities.[33]

Complications

Concomitant urinary symptoms may be complicated by pelvic organ prolapse. Thus, when working up a patient for POP, it is essential to retract the bulge and assess for signs of urinary incontinence masked by prolapse.[14] Additionally, fecal incontinence and obstruction can be a significant complication of POP. Many patients can describe the splinting in which a finger in the vagina is required to aid in defecation.[13]

Although treatment with a pessary has an impressive success rate, there are some complications patients should be informed about before placement. If the patient presents to follow-up with vaginal discharge, irritation, ulceration, bleeding pain and odor, vaginal wall ulceration, fistula formation, or bowel herniation, pessary complications should be suspected.[34] Infection with anaerobes, such as bacterial vaginosis, is highly common in women who change their pessaries less than once weekly.[35] Vaginal ulceration and bleeding occur more commonly in postmenopausal women and with less frequent pessary removal. 

Many complications in the treatment of POP have been associated with mesh insertion. The use of transvaginal mesh and biological graft material in prolapse surgery is controversial and has led to many inquiries into their safety and efficacy. Recently, the FDA has abandoned the use of large mesh grafts in the vagina in the correction of pelvic organ prolapse, and vaginal repair is limited to the use of either native tissue or a biological graft.[36] High-risk mesh-related complications include infection and dyspareunia. Mesh with a pore size <10 micrometers allows bacterial, but not macrophage infiltration, and can lead to high infection rates.[37]