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Pelvic Organ Prolapse
What leads to pelvic organ prolapse?
It is sometimes difficult for women to understand the changes that take place when the bladder, uterus or vagina fall. The following material is provided to help improve women’s understanding of the problems that they experience.
The position of the vagina relative to the rest of the body is somewhat like the finger of a surgical glove which is tucked inside the rest of the glove. In this way, the vagina is surrounded by an enclosed area. If the pressure in that area is increased, so that the finger of the surgical glove is being squeezed, the vagina tends to be pushed downward and to protrude outward.
What are the normal anatomical supports?
There are two basic ways in which the body prevents this from happening. One way is a small, muscular band that prevents the vagina from being pushed downward by closing the opening of the vagina. This is the role that the pelvic muscles play. The other way are “ligaments” that hold the walls of the vagina up to the sides of the body in a way that prevents downward descent. These two different strategies, which are present in normal women, help to prevent the vagina and uterus from falling out.
When the pelvic muscles are damaged, the muscles are no longer able to hold the opening of the vagina closed. As a result, these tissues sag downward and the ligaments are called upon to hold the organs in place. Therefore, both the ligaments and the muscles are needed for the organs such as the bladder, uterus, and vagina to be held in their normal position.
The uterus, the bladder, the rectum, and the vagina all lie within the bottom of the abdominal cavity, and so the structures in this area must bear the weight of the contents of the abdomen. Similarly, the pelvic floor, located at the bottom of the pelvis, acts like a box and must carry the weight of the contents with the sides and top of “the box” having relatively less force placed upon them.
The normal muscles that hold the vagina closed also support the organs. As is true with the muscles in your back, these are not muscles you think about controlling. The body simply has them adjust to maintain just the right amount of contraction to hold things in place. This is somewhat like the muscles that hold the rectum and anus closed. It is only during certain times such as those in which gas is pushing down that we actually think about those muscles and contract them. The rest of the time these muscles are run automatically by the body.
What are the different types of prolapse that women can have?
There are several different types of prolapse that a woman can have. If the anterior vaginal wall and bladder fall down, it is called a cystocele. If the posterior vaginal wall and rectum fall down it is called a rectocele. When the uterus falls down, it is called a uterine prolapse. Also, sometimes, a space develops between the vagina and rectum into which a small bowel can bulge. This is referred to as an enterocele. In women who have previously had a hysterectomy, it is still possible for the top of the vagina to fall down, even though the uterus is no longer there. This is referred to as a post hysterectomy (“after hysterectomy”) vaginal prolapse. This system can fail in different places. Depending on the location of the damage, a different part of the pelvic organs may fall down.
The way to see the downward falling of the organs is to imagine an individual straining like they would do to push out a bowel movement or to lift something heavy.
The most common problem seen is a cystocele, where the bladder is pushed downward below its normal position. The bladder falls down below its normal position, which increases the pressure in the abdomen because the muscles are not strong enough to hold it in place and the ligaments are not supporting it.
A similar problem that involves the rectum is clinically called a rectocele. This is where the rectum descends below the normal place that it is held and comes out to protrude below this area.
It is also possible for women to have prolapse of the uterus. This is where the uterus descends through the opening of the vagina, although the rectum and the bladder are held in a relatively normal position. It is this downward motion of the uterus that is the abnormality, and this woman would be able to feel the end of her uterus, called the cervix, coming out through the opening of the vagina.
There are obviously different combinations of these problems, and an individual can have a uterine prolapse as well as a cystocele or a rectocele.
Why does pelvic organ prolapse happen?
Pelvic organ prolapse occurs because the forces pushing the uterus and vagina down are greater than the strength of the muscles and ligaments that hold them in place. This leads to a downward movement of the organs.
The damage to the pelvic muscles can occur when a woman delivers a baby. The muscles have to stretch a great deal for the baby to come out of the vagina. Sometimes during the delivery process, the muscle is injured. When the pelvic muscles heal, it may not be as strong as it was in the first place. In other cases, the nerve that controls the muscle is damaged. As a result, the muscle does not contract. This is similar to the way that someone with a spinal cord injury loses their ability to control the muscles that are not connected to the spinal cord and brain. In most women, this damage is minor, but in others, enough muscle may be lost that it can no longer hold the pelvic organs up. Age also affects the muscles. In general we become a little weaker with each year that we grow older. A 60 year old is weaker than a 25 year old. This happens with the muscles of the pelvic floor as well.
The organs rest on the muscular floor which sort of acts like a trap door. If you were standing on a trap door and the door drops down, unless you have something to hold on to, you would fall through. With the organs, when this happens, the pelvic floor opens up and the organs begin to prolapse downward. Eventually, the ligaments catch them and hold them in place, but as we will see later, this puts a lot of stress on the ligaments.
The ligaments are normally strong enough to hold the pelvic organs in place for a while, even if the muscles are weak or damaged. They can, however, become damaged and weakened. Vaginal delivery may cause a ligament to break as the baby’s head comes through the pelvic floor. Age causes ligaments to weaken in some women in the same way that skin sags as we age. Also, other things that may make ligaments weaker include chronic smoking and some diseases. Each of these things can lead to weakening and breakage of the ligaments that help hold the pelvic organs in place. The inherent strength of the ligaments in one woman can also differ from the strength of ligaments in another woman. Women born with weak ligaments are more prone to problems with prolapse than those born with sturdier ligaments. This is a reason why women in some families are more prone to developing a prolapse than women in other families.
When the ligaments become weakened and then break, they may no longer hold the organs in a place where the muscles can support them; or when the muscles are damaged, they may not be strong enough to hold the organs in place.
Can prolapse happen because the stresses on the muscles and ligaments are too great?
Any structure can be broken when it is subjected to too much force. For example, if a large adult was to sit on a small child’s swing, it would most likely break. Similarly, if the muscles and ligaments are stressed beyond their limits, they may fail. Chronic coughing, working in a job where lots of heavy lifting is needed, and probably obesity, all put unusual pressures on the pelvic floor. These may not damage the pelvic floor in all women, but in those who are susceptible to this condition; these may be factors that could provoke a prolapse.
How does damage to the ligaments and muscles result in prolapse?
When the muscles are damaged and the pelvic floor opens, the force of the abdominal pressure pushes the vagina down. In a young woman, who does not have any damage to her muscles, these muscles close the pelvic floor so none of the organs fall down. When the muscles have been damaged and fall open, then the ligaments must bear an increased burden. With weakened or broken ligaments, the organs may fall through the opening in the pelvic floor. If it is predominantly the ligaments that are attached to the front wall of the vagina that fail, then the bladder falls and a cystocele develops. If it is predominantly the ligaments that are attached to the back wall of the vagina that fail, then a rectocele develops. If these ligaments are fine, but the ligaments that attach the uterus in place fail, then a uterine prolapse develops.
Information provided by UMHS Urogynecology Clinic, Deb Czarnota, RN - March, 2009.