Pelvic Organ prolapse
Pelvic organ prolapse is a condition denoting the descent of pelvic organs toward or through the vaginal opening. References to prolapse of the womb have first been made in ancient Egypt dating back to 1550 BC. Vaginal vault prolapse refers to significant descent of the vaginal apex (“the top of the vagina”) following a hysterectomy. Although obviously not a new condition, prolapse is becoming increasingly common due to increased life expectancy.
Prolapse of the top of the vagina or uterus is rarely an isolated finding. The anterior vagina (front side or the bladder side of the vagina) and the posterior vagina (back or rectal side of the vagina) can and often do protrude independent of the uterus or the apex. Protrusion of the anterior vagina is also called a cystocele, while posterior vaginal prolapse is called a rectocele, named after the organs which are thought to descend along with the vagina, the bladder, and rectum. Prolapse of the vaginal apex can, but need not necessarily, be accompanied by an enterocele. Enterocele is defined as the presence of abdominal contents (such as small bowel or omentum) dissecting between the vagina and the adjacent rectum.
Patients may present with an obvious vaginal bulge that is seen or felt by the woman. Conversely, she may complain of a vague sense of pelvic heaviness or a sensation as if “something is about to fall out.” Bulging is often noted to be worse toward the end of the day when compared to when she first awakes. When the vaginal lining remains exteriorized for a prolonged period of time, it undergoes thickening from the constant rubbing on undergarments. The vaginal tissue may develop sores (ulcers) and become infected. Urinary incontinence as well as difficulty voiding is common with pelvic organ prolapse and in severe cases complete urinary retention may be seen. Voiding difficulties may result in frequent urinary tract infections and, occasionally, overflow incontinence. Due to kinking of the urethra, urinary incontinence may be masked, in which case the woman does not think she has incontinence, but if the prolapse is fixed surgically or otherwise without further attention to the problem, severe incontinence may surface. Especially concerning the presence of occult stress incontinence, is a history of stress incontinence that spontaneously improved and/or resolved as the prolapse progressively worsened. Although rare, severe pelvic prolapse may result in kinking of the ureters with the potential for kidney damage.
Difficulties may be encountered during sexual intercourse. Defecation may be difficult with associated constipation being very common.
FREQUENCY AND ETIOLOGY
In a routine gynecologic clinic population, most women had mild to moderate prolapse (43.3% and 47.7%, respectively) and few had no or severe prolapse (6.4% and 2.6%, respectively). Complete eversion of the vagina is even more rare. If one imagines the vaginal tube analogous to a sock, complete eversion is similar to completely turning the sock inside-out.
Significant trends for increasing prolapse were found with advancing age, number of children, postmenopausal status, hysterectomy, and prior surgery for prolapse. A Swedish study of the general population reported a prevalence of 30% of any prolapse. Statistical associations with age, number of children, maximal birthweight, and pelvic floor muscle strength were found. Such associations were not found regarding the woman’s weight or history of hysterectomy. Indeed, vaginal vault prolapse is thought to occur in less than 0.5% of patients who have had hysterectomies, whether done vaginally or abdominally.
The anatomy of pelvic organ prolapse can be understood in terms of three levels of support. Level I represents the support of the top part of the vagina in terms of the cervix (with no prior hysterectomy) or the vaginal cuff (in a woman who has undergone total hysterectomy) by the cardinal-uterosacral ligament complex. This is analogous to the toe of the sock being suspended by two ropes, one on either side. The cardinal-uterosacral ligament complex serves to keep the upper vagina and uterus resting on the levator ani muscles, which comprise the majority of the pelvic diaphragm that rests in a near-horizontal plane in a woman standing erect. Level II denotes the lateral support of the midvagina to the pelvic sidewall. Level III is represented by the fusion of the distal vagina (the opening of the sock) to tissue of the perineum.
The U-shaped levator ani muscles, as long as they are functioning properly, essentially support the pelvic organs by preventing their descent through the hiatus (the opening of the “U”). Once the muscles cease to function properly the structures described earlier come under increasing tension and are apt to fail. The conditions of enterocele and apical prolapse represent failures of level I support. Apical prolapse occurs due to tearing or attenuation of the cardinal-uterosacral ligaments (the ropes). This results in failure to support the top part of the vagina and uterus over the pelvic diaphragm. Enterocele following a hysterectomy is analogous to opening of the stitch along the toe of the sock. Level I support is considered the most important in maintaining adequate overall pelvic support, because once that fails, usually the pressures exerted will result in further failure of the support systems. Failure of level II support results in a cystocele and/or rectocele. Failures of level III are very rare and limited to women who have undergone radical vulvar surgery.
A cystocele, named after the organ that descends with the anterior vagina—the bladder, occurs due to the fact that the bladder sits passively atop the anterior vaginal wall. If the support of the anterior vagina is compromised, the bladder will follow the vagina down its descent toward the vaginal opening. This support may be compromised in several ways. One way it can be compromised is if one or both of its sidewalls break away from the pelvic sidewall. If one imagines the anterior vagina as a trampoline, this is analogous to the breakage of the springs on opposite sides. Another way is by breakage of the strong layer of tissue in its midportion, which is analogous to ripping the tarmac that represents the trampoline’s surface. A final method is due to general attenuation of the vagina, which is analogous to having the fabric of the tarmac fray and get worn with repeated use in a particular spot on the trampoline.
It has been suggested that early, persistent, and well-performed pelvic floor muscle exercises (Kegel exercises) may be helpful in preventing pelvic organ prolapse and may slow the progression of early signs of prolapse. Success depends upon early intervention and exercising the correct muscle group, which is best verified during a pelvic examination. The levator ani muscles are the target of such exercises and are comprised of two types of muscle fibers: slow twitch and fast twitch. Proper exercising involves utilizing and strengthening these two types of muscle fibers. One component of exercise is maximal contraction of the muscle over a period of time, the other is rapid maximal contraction followed by relaxation done in sequence. The difficulty of the exercise routine is gradually increased by increasing the amount of time on the continuous contraction exercises while increasing the number of consecutive quick contractions. It is now possible to find physical therapists able to work with patients on this problem.
A pessary is a medical device that is worn in the vagina to help prevent protrusion of the prolapse. Most pessaries are made of silicon and they come in various shapes and different sizes. Some remain in the vagina for months at a time, while others can be removed and reinserted by the patient. Some allow sexual intercourse, while others do not. Although pessaries do not cure the problem, they are appropriate as an option to avoid the need for surgery in motivated patients. Pessaries must be properly fitted by an experienced clinician and removed for vaginal inspection on a routine basis because the biggest risks of pessary use result from their neglect for a prolonged period of time.
Surgery is reserved for patients who have significant symptoms related to their pelvic organ prolapse. Multiple procedures are available, which can be done through a vaginal or abdominal route. The key to the decisionmaking process, however, is careful evaluation of all pelvic floor defects both in the office and during the surgery and addressing each of them at the time of surgery. Careful consideration for the potential risks and benefits of surgery should be done prior to any such undertaking.
SEE ALSO: Hysterectomy, Kegel exercises, Urinary incontinence and voiding dysfunction
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- Uterine prolapse pathogenesis