Female urology encompasses urinary incontinence as well as pelvic reconstructive medicine for prolapse. It is common for urinary incontinence and pelvic organ prolapse to coexist in the same woman or to develop subsequently. This chapter will concentrate on pelvic organ prolapse as urinary incontinence has been discussed in detail in Chapter 29.
Pelvic organ prolapse is the protrusion of the pelvic organs (uterus, bladder, and bowel) into or past the vaginal introitus. Estimates of prevalence vary widely depending on definition used, whether the patient is symptomatic, the epidemiologic methods used, and the population studied. The U.S. National Center for Health Statistics estimates over 250,000 operations performed for genital prolapse apart from hysterectomy. With aging of the population, these quality of life issues and their treatment assume additional importance.
The maintenance of continence and prevention of pelvic organ prolapse rely on the support mechanisms of the pelvic floor. The bony pelvis is the rigid foundation to which all of the pelvic structures are ultimately anchored. These bones are the ilium, ischium, pubic rami, sacrum, and coccyx. It is important to understand and discuss the bony pelvis from the perspective of a standing woman. In the upright position, the bony arches of the pelvic inlet are oriented in an almost vertical plane (Figure 40–1). This directs the pressure of the intra-abdominal and pelvic contents toward the bones of the pelvis instead of the muscles and fascial attachments of the pelvic floor. This dispersion of forces minimizes the pressure on the pelvic musculature and transmits them to the bones that are better suited to the long-term cumulative stress of daily life.
Orientation of the bony pelvis in an upright woman. (Reproduced, with permission, from Drake RL et al (eds): Gray's Anatomy for Students. Churchill Livingston, Philadelphia, 2005.)
The muscles of the pelvic floor, particularly the levator ani muscles, have a critical role in supporting the pelvic organs and play an integral role in urinary, defecatory, and sexual function. The levator muscle complex consists of the pubococcygeus, the puborectalis, and the iliococcygeus (Figure 40–2). The pubococcygeus originates on the posterior inferior pubic rami and inserts on the midline organs and the anococcygeal raphe. The puborectalis also originates on the pubic bone, but its fibers pass posteriorly and form a sling around the vagina, rectum, and perineal body, resulting in the anorectal angle and promoting closure of the urogenital hiatus. The iliococcygeus originates from the arcus tendineus levator ani (ATLA) and inserts in the midline onto the anococcygeal raphe.
Muscular support of the pelvis. The pubococcygeus, the puborectalis, and the iliococcygeus comprise the levator ani muscles. (Reproduced, with permission, from Walsh PC et al ...