Pelvic Organ Prolapse: Anterior Prolapse
Pelvic organ prolapse is defined as the descent of one or more of the anterior vaginal wall, posterior vaginal wall, the uterus, or the apex of the vagina (vaginal vault or cuff scar after hysterectomy).1 Anterior vaginal wall prolapse/cystocoele is the descent of the anterior vaginal wall and can be due to central and/or paravaginal fascial defects. Uterine or vaginal vault descent and enterocele are often seen in combination with cystocoele.
It is difficult to identify the true prevalence of symptomatic cystocoele as most of the estimates are based on patients admitted to hospital for surgery. It is estimated that in the general population, prolapse of the anterior wall occurs in 14% to 27% of women and, in combination with other sites, in 33% of cases.2,3 The Women’s Health Initiative showed that in women ages 50 to 75 years, 41% had various degrees of pelvic organ prolapse of which 34% were cystocoeles.4
Anterior vaginal wall prolapse rises in both prevalence and incidence with age. The Women’s Health Initiative revealed that women in the age groups 60 to 69 years and 70 to 79 years had a higher risk of prolapse than the 50- to 59-year age group.4 Regarding new onset of cystocoeles, Handa et al. found that these occurred in 9% of women per year; however, spontaneous regression was common, especially with grade one prolapse.5 In older parous women prolapse is more likely to be progressive than regressive.6
From cadaver studies, DeLancey defined three levels of pelvic support.7 Level I accounts for support of the upper third of the vagina and the cervix. Level II involves the middle third of the vagina and its attachment to the pelvic side walls laterally by fascia extending transversely between the bladder and the rectum attaching to the arcus tendineus fascia pelvis (ATFP) and the superior fascia of the levator ani.7 Loss of level II support results in the formation of cystocoeles and rectocoeles. The lower third of the vagina fuses with the perineal membrane, perineal body, and levator ani and this forms level III.7
Support of the pelvic organs depends on the striated muscle and its nerve supply, as well as fascia and connective tissue. Disruption of any or all of these can lead to pelvic organ prolapse.
Under normal circumstances the pelvic organs are supported by both the pelvic muscles and connective tissue. The levator ani muscle has both slow twitch (type 1) and fast twitch (type 2) fibers with the former providing resting tone and the later preventing stretching of the pelvic ligaments. Women with prolapse more often have defects in the levator ani and generate less vaginal closure force during a maximal contraction when compared to ...