Enterocele has been defined as a peritoneum-lined sac her-niating through the pelvic floor, usually between the vagina and rectum. Nichols and Randall described four types, including traction, congenital, pulsion, and iatrogenic. Traction enterocele is probably the most common and occurs secondary to uterine and vaginal apical prolapse. Cystocele and rectocele usually coexist with traction ente-rocele. Congenital enterocele is rare and may result from connective tissue and neurologic disorders such as spina bifida. Congenital enterocele may occur independently of other types of prolapse. Pulsion enterocele results from prolonged increases in intraabdominal pressure and may be accompanied by massive prolapse. Finally, iatrogenic enterocele results after postsurgical elevation of the vaginal axis out of its normally horizontal axis toward the vertical plane, as may occur after colposuspension.
The pathophysiology of enterocele has been debated. One theory proposes a defect in the fibromuscular vaginal tube with a discreet defect of the pubocervical and recto-vaginal muscularis at the vaginal apex. This theory proposes that prolapse results from discrete breaks in the endopelvic fascia rather than from stretching or attenuation. Histologic samples of peritoneum directly abutting vaginal epithelium (without intervening muscularis) have been reported but are few. In another histologic study of enteroceles, 13 women with posthysterectomy prolapse and enterocele were compared with 5 women undergoing hysterectomy without prolapse and 13 women undergoing radical hysterectomy. No women with enterocele had peritoneum directly in contact with vaginal epithelium. Average vaginal wall muscularis thickness was similar among the three groups, with a slightly thicker muscularis in those with enterocele. This study suggested that ente-rocele was mainly caused by a loss of the vaginal support to the endopelvic fascia.