ANATOMY AND PATHOLOGY

Anterior vaginal prolapse (cystocele) is defined as pathologic descent of the anterior vaginal wall and overlying bladder base. According to the International Continence Society (ICS) standardized terminology for prolapse grading, the term anterior vaginal prolapse is preferred over cystocele. The reason is because information obtained at the physical examination does not allow the exact identification of structures behind the anterior vaginal wall, although, in fact, it is usually the bladder. The ICS grading system for prolapse is discussed fully in Chapter 5.

The cause of anterior vaginal prolapse is not completely understood, but it is probably multifactorial, with different factors implicated in prolapse in individual patients. Normal support for the vagina and adjacent pelvic organs is provided by the interaction of the pelvic muscles and connective tissue, as discussed in Chapter 2. The upper vagina rests on the levator plate and is stabilized by superior and lateral connective tissue attachments; the midvagina is attached to the arcus tendineus fasciae pelvis (white line) on each side. Pathologic loss of that support may occur with damage to the pelvic muscles, connective tissue attachments, or both.

Nichols and Randall (1996) described two types of anterior vaginal prolapse: distention and displacement. Distention was thought to result from overstretching and attenuation of the anterior vaginal wall, caused by overdistention of the vagina associated with vaginal delivery or atrophic changes associated with aging and menopause. The distinguishing physical feature of this type was described as diminished or absent rugal folds of the anterior vaginal epithelium caused by thinning or loss of midline vaginal fascia. The other type of anterior vaginal prolapse, displacement, was attributed to pathologic detachment or elongation of the anterolateral vaginal supports to the arcus tendineus fasciae pelvis. It may occur unilaterally or bilaterally and often coexists with some degree of distention cystocele, with urethral hypermobility, or with apical prolapse. Rugal folds may or may not be preserved.

Figure 19-1 Three different defects can result in anterior vaginal wall prolapse. Lateral or paravaginal defects occur when there is a separation of the endopelvic fascia from the arcus tendineus fasciae pelvis, midline defects occur secondary to attenuation of fascia supporting the bladder base, and transverse defects occur when the endopelvic fascia separates from the vaginal cuff or uterosacral ligaments.

(From Karram MM. Vaginal operations for prolapse. In Baggish MS, Karram MM, eds. Atlas of Pelvic Anatomy and Gynecologic Surgery. WB Saunders, Philadelphia, 2001, with permission.)

Few systematic or comprehensive descriptions of anterior vaginal prolapse have emerged based on physical findings and correlated with findings at surgery to provide objective evidence for any of these theories of pathologic anatomy. In a study of 71 women with anterior vaginal wall prolapse and stress incontinence who underwent retropubic operations, DeLancey (2002) described paravaginal defects in 87% on the left and 89% on the right. The arcus tendineus fasciae pelvis were usually attached to the pubic bone but detached from the ischial spine for a variable distance. The pubococcygeal muscle was visibly abnormal with localized or generalized atrophy in over half of the women.

Recent improvements in pelvic imaging are leading to a greater understanding of normal pelvic anatomy and the structural and functional abnormalities associated with prolapse. Magnetic resonance imaging (MRI) holds great promise, with its excellent ability to differentiate soft tissues and its capacity for multiplanar imaging. Further work is needed to correlate the different images with anatomy and histology under normal conditions and with pelvic support abnormalities.

The pelvic organs, pelvic muscles, and connective tissues can be identified easily with MRI. Various measurements can be made that may be associated with anterior vaginal prolapse or urinary incontinence, such as the urethrovesical angle, descent of the bladder base, the quality of the levator muscles, and the relationship between the vagina and its lateral connective tissue attachments. Aronson et al. (1995) used an endoluminal surface coil placed in the vagina to image pelvic anatomy with MRI, and compared four continent nulliparous women with four incontinent women with anterior vaginal prolapse. Lateral vaginal attachments were identified in all continent women. In Figure 19-2, the posterior pubourethral ligaments (bilateral attachment of arcus tendineus fasciae pelvis to posterior aspect of the pubic symphysis) are seen clearly. In the two subjects with clinically apparent paravaginal defects, lateral detachments were evident (Fig. 19-3). Although this study involved only a small number of subjects, it provides the basis for further work in describing the anatomic abnormalities that accompany anterior vaginal prolapse and other abnormalities of pelvic support. This, ultimately, may guide the choice of surgical repair.

Figure 19-2 Axial T₁-weighted image from a continent 38-year-old nulliparous woman, showing the connection of the anterior vaginal wall (v) to the posterior pubic symphysis (p) by the pubourethral ligaments (pul). The anterior vaginal wall and endopelvic fascia function as a sling or hammock for support of the urethra (u). o, Obturator internus muscle; r, rectum; l, levator ani musculature.

(From Aronson MP, Bates SM, Jacoby AF, et al. Periurethral and paravaginal anatomy: an endovaginal magnetic resonance imaging study. Am J Obstet Gynecol 1995;173:1702, with permission.)

Figure 19-3 Axial T₁-weighted image from a 57-year-old woman, para 5, with stress urinary incontinence. The paravaginal detachment (arrow) is seen at the level of the urethrovesical junction. v, Anterior vaginal wall; p, posterior pubic symphysis; u, urethra; o, obturator internus muscle; c, endovaginal coil; r, rectum; l, levator ani musculature.

(From Aronson MP, Bates SM, Jacoby AF, et al. Periurethral and paravaginal anatomy: an endovaginal magnetic resonance imaging study. Am J Obstet Gynecol 1995;173:1702, with permission.)

EVALUATION

History

When evaluating women with pelvic organ prolapse or urinary or fecal incontinence, attention should be paid to all aspects of pelvic organ support. The reconstructive surgeon must determine the specific sites of damage for each patient, with the ultimate goal of restoring both anatomy and function.

Patients with anterior vaginal prolapse complain of symptoms directly related to vaginal protrusion or of associated symptoms, such as urinary incontinence or voiding difficulty. Symptoms related to prolapse may include the sensation of a vaginal mass or bulge, pelvic pressure, low back pain, and sexual difficulty. Stress urinary incontinence commonly occurs in association with anterior vaginal prolapse. Voiding difficulty may result from advanced prolapse. Women may require vaginal pressure or manual replacement of the prolapse to accomplish voiding. Women may relate a history of urinary incontinence that has since resolved with worsening of their prolapse. This can occur with urethral kinking and obstruction to urinary flow; women in this situation are at risk for incomplete bladder emptying and recurrent or persistent urinary tract infections and for the development of de novo stress incontinence after the prolapse is repaired.

Physical Examination

The physical examination should be conducted with the patient in the lithotomy position, as for a routine pelvic examination. The examination is first performed with the patient supine. If physical findings do not correspond to symptoms, or if the maximum extent of the prolapse cannot be confirmed, the woman is reexamined in the standing position. The grading systems for prolapse and measurement of urethral hypermobility are described in Chapters 5 and 6.

The genitalia are inspected, and, if no displacement is apparent, the labia are gently spread to expose the vestibule and hymen. The integrity of the perineal body is evaluated, and the approximate size of all prolapsed parts is assessed. A retractor or Sims speculum can be used to depress the posterior vagina to aid in visualizing the anterior vagina. After the resting examination, the patient is instructed to strain down forcefully or to cough vigorously. During this maneuver, the order of descent of the pelvic organs is noted, as is the relationship of the pelvic organs at the peak of straining.

It may be possible to differentiate lateral defects, identified as detachment or effacement of the lateral vaginal sulci, from central defects, seen as midline protrusion but with preservation of the lateral sulci, by using a curved forceps placed in the anterolateral vaginal sulci directed toward the ischial spine. Bulging of the anterior vaginal wall in the midline between the forceps blades implies a midline defect; blunting or descent of the vaginal fornices on either side with straining suggests lateral paravaginal defects. Studies have shown that the physical examination technique to detect paravaginal defects is not particularly reliable or accurate. In a study by Barber et al. (1999) of 117 women with prolapse, the sensitivity of clinical examination to detect paravaginal defects was good (92%), yet the specificity was poor (52%) and, despite an unexpected high prevalence of paravaginal defects, the positive predictive value was poor (61%). Less than two thirds of women believed to have a paravaginal defect on physical examination were confirmed to possess the same at surgery. Another study by Whiteside et al. (2004) demonstrated poor reproducibility of clinical examination to detect anterior vaginal wall defects. Thus, the clinical value of determining the location of midline, apical, and lateral paravaginal defects remains unknown.

Anterior vaginal wall descent usually represents bladder descent with or without concomitant urethral hypermobility. In 1.6% of women with anterior vaginal prolapse, an anterior enterocele mimics a cystocele on physical examination.

Diagnostic Tests

After a careful history and physical examination, few diagnostic tests are needed to evaluate patients with anterior vaginal prolapse. A urinalysis should be performed to evaluate for urinary tract infection if the patient complains of any lower urinary tract dysfunction. If the patient’s estrogen status is unclear, a vaginal cytologic smear can be obtained to assess maturation index. Hydronephrosis occurs in a small proportion of women with prolapse; however, even if identified, it does not usually change management in women for whom surgical repair is planned. Therefore, routine imaging of the kidneys and ureters is not necessary.

If urinary incontinence is present, further diagnostic testing is indicated to determine the cause of the incontinence. Urodynamic (simple or complex), endoscopic, or radiologic assessments of filling and voiding function are generally indicated only when symptoms of incontinence or voiding dysfunction are present. Even if no urologic symptoms are noted, voiding function should be assessed to evaluate for completeness of bladder emptying. This procedure usually involves a timed, measured void, followed by urethral catheterization or bladder ultrasound to measure residual urine volume.

In women with severe prolapse, it is important to check urethral function after the prolapse is repositioned. As demonstrated by Bump et al. (1988), women with severe prolapse may be continent because of urethral kinking; when the prolapse is reduced, urethral dysfunction may be unmasked with occurrence of incontinence. A pessary, vaginal retractor, or vaginal packing can be used to reduce the prolapse before office bladder filling or electronic urodynamic testing. If urinary leaking occurs with coughing or Valsalva maneuvers after reduction of the prolapse, the urethral sphincter is probably incompetent, even if the patient is normally continent. This situation is reported to occur in 17% to 69% of women with stage III or IV prolapse. In this situation, the surgeon should choose an anti-incontinence procedure in conjunction with anterior vaginal prolapse repair. If sphincteric incompetence is not present even after reduction of the prolapse, an anti-incontinence procedure may not be indicated.