The anterior vaginal wall is the most common site of initial pelvic organ prolapse. It is estimated that 80% of surgical repairs for vaginal wall prolapse involve the anterior compartment. It is also the most frequent site of operative failure. Reported rates of operative failure have run as high as 40%—much higher than rates of failure after posterior wall repairs.
There are several possible reasons the anterior vaginal wall may be more susceptible to prolapse and more difficult to repair. It could be that the anterior wall is not as well supported by the levator plate that counters the effects of gravity and abdominal pressure. Normally the anterior wall rests horizontally on the posterior wall, and the posterior wall rests on the levator plate. When levator muscles weaken and increasing force is placed on the connective tissue supports, the anterior wall may be the first compartment to fall. It is also possible that the attachments of the anterior compartment to the pelvic sidewall or to the apex are weaker, or that the anterior wall itself is more elastic or less dense, or perhaps it is more susceptible to damage during childbirth or weakening with aging. For most women, anterior vaginal wall prolapse is probably the result of a combination of these factors.
Management of anterior wall prolapse is consequently a significant challenge—one that has led surgeons to use various graft materials to reduce the rate of failure of transvaginal repair and subsequent prolapse recurrence. Several studies have shown improvements in short-term recurrence rates, but long-term durability and safety of mesh-reinforced repair is unclear. We need a more complete assessment of the anatomic and symptomatic efficacy of graft use in transvaginal repair.
The traditional anterior colporrhaphy with attention to apical suspension remains the preferred method for primary repairs. Apical attachment can be accomplished through a sacrocolpopexy, uterosacral ligament suspension, or sacrospinous ligament suspension. Sacrocolpopexy provides both apical and midline support for the anterior wall. For many surgeons, including myself, a sacrocolpopexy is the procedure of choice for women with a cystocele and apical descent.
Anatomy and Evaluation
Understanding pelvic floor anatomy—and the trapezoidal anatomy of the anterior vaginal wall—is critical to understanding the various types of cystocele and their repair. The trapezoidal plane of the anterior wall results from the ventral and more medial attachments near the pubic symphysis and the dorsal and more lateral attachments near the ischial spine. The wall is suspended on both sides to the parietal fascia overlying the levator ani muscles at the arcus tendineus fascia pelvis (ATFP).
The type of cystocele is defined by where there is a break in the fascial attachments to the pelvic sidewall. A loss of lateral attachment causes what we know as a paravaginal defect, or displacement cystocele. The goal of the paravaginal repair, therefore, is to reattach the lateral vaginal walls to the ATFP.
A transverse cystocele occurs when the top of the pubocervical fascia detaches from the cervix or vaginal apex; it is evidenced by the loss of anterior fornix. (When a transverse cystocele occurs following a hysterectomy, the prolapse frequently includes an enterocele and loss of apical support that must also be repaired.) Central or distal cystoceles involve a loss of support near the pubis and tend to manifest as urethral hypermobility.
When one considers the trapezoidal anatomy of the anterior vaginal wall, the importance of restoring apical support is clear. Several studies have shown that variations in cystocele type and severity are often determined by the degree of apical support. Dr. John O.L. DeLancey and his associates, for instance, found that anterior wall prolapse was due to loss of apical support in one-half of women whose prolapse was measured on MRI scans (Am. J. Obstet. Gynecol. 2006;194:1438-43).
In another evaluation—a cohort study of 325 women—investigators similarly found that anterior vaginal wall prolapse was strongly associated with apical prolapse, and concluded that anterior vaginal wall defects that are surgically repaired usually require concomitant repair of the apex (Am. J. Obstet. Gynecol. 2006;195:1837-40).
Just as with posterior vaginal wall prolapse, one must first determine which part of the patient's support mechanism has failed. A careful physical evaluation must be done to identify the sites of defects and detachments. By supporting the lateral anterior walls at the level of the ATFP with a ring forceps, one can identify paravaginal defects and determine the role of apical failure.
While supporting the apex with a ring forceps, I ask the patient to bear down or cough. If her anterior wall remains in place and her cystocele disappears, I know an apical suspension is needed at the time of surgery. If she still has some relaxation, an apical suspension as well as an anterior colporrhaphy are needed.