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Rectal Descent

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What is rectal descent?

Some people have great difficulty emptying their rectum due to what is called rectal descent. Rectal descent is a problem that appears to be related to childbirth. When a women gives birth, the normal attachments of the rectum to the lower backbone may get stretched or torn. This tearing allows the rectum to fall into the pelvis where it assumes a horizontal position. The front of the rectum can fall into the top of the anal canal and block the anal opening.

An llustration depicting rectal descent.

How does the rectum work?

The normal rectum lies against the sacrum (lower backbone) in a gentle curve down to the anal opening. When a person moves his bowels, the muscles of the pelvic floor relax and the rectum swings down and straightens so it is almost straight up and down (vertical) over the anal opening. In this way the rectal contents can move straight out.

When a person pushes to move his bowels, it increases the abdominal pressure. If the rectum is attached to the sacrum properly, the increased abdominal pressure squeezes the rectal contents out like toothpaste from a tube. The rectum is a soft pliable tube. If it is not firmly supported by the lower backbone, it slides down in the pelvis and blocks the anal opening.

Let us compare the rectum to a sock. If you support the sock with one hand on either side of the top open end, then it is easy to put your foot into it and slide it all the way inside. If, however, the sock is lying on the floor not supported or held in place, then it will be very hard to put your foot into it, much less get your foot all of the way in. The same is true of the rectum. The hands supporting the sock are represented by the attachments of the top of the rectum to the backbone.

What are the symptoms of rectal descent?

Knowing this, you can predict the complaints that people with rectal descent have. If they don't have colonic inertia, they will have the usual amounts of stool getting down to the rectum daily. They will feel the urge to move their bowels; but, even with straining, the rectum will not empty. This differs from someone with colonic inertia. Someone with colonic inertia may not feel the need to move his bowels for a week or more at a time. Someone with rectal descent without colonic inertia will feel the need to move his bowels every day.

Patients with rectal descent take a long time to have a bowel movement. Even after they move their bowels, it may feel as if their rectum is still not empty.

They may feel as if their rectum is dropping out of their pelvis. They may feel a weight down on the bottom of their pelvis. A woman may feel a mass pushing against her vagina.

People with rectal descent have difficulty emptying their rectum. They must strain to move their bowels. They may have to put their fingers into their rectum or (in the case of a woman) vagina, or push on their pelvic area, to get their bowels to move.

When we operate on people with rectal descent we sometimes see that the rectum has fallen down into the pelvis and is just lying flat on the floor of the pelvis.

Before talking about how to correct rectal descent let us discuss some other forms of rectal descent. The first is solitary rectal ulcer.

Solitary Rectal Ulcer

Sometimes rectal descent causes the front wall of the rectum to flop into the anal canal. Straining causes pressure on the front wall of the rectum and a pressure sore develops. This sore is called a solitary rectal ulcer. It has a white base and sharp distinct edges. When we see it, we can be certain that rectal descent is present. This solitary rectal ulcer can cause pain and bleeding. One person bled so much from her solitary rectal ulcer that she needed to receive seven units of blood. This can also occur in males.

Rectocele

Rectocele is a bulge of the lower rectum into, over or behind the vagina. Rectoceles trap stool and may not empty. Rectoceles are probably more common in women after a hysterectomy. The rectum falls into the place of the uterus. The woman with a rectocele may need to put her finger into the vagina to push the stool out. Defecography demonstrates the rectum bulging forward.

Stool softeners and fiber may help. If they do not, surgery may be needed.

Rectoceles can only occur if the attachments between the rectum and the vagina are weakened, and if extra rectum is dragged down or stretched out to form the pouch.

If the rectocele causes difficult rectal emptying, the associated rectal descent should be corrected. The surgery recommended for a symptomatic rectocele is the same operation done for rectal descent.

A type of rectocele repair can be done through the vagina, but this does not correct rectal descent. It often does not correct the rectal emptying problems associated with rectoceles.

We can usually confirm that a woman has rectal descent by talking to her and examining her. We must confirm the diagnosis with defecography. Defecography uses video X-rays to look at the shape and position of the rectum as it empties.

Rectal Prolapse

An llustration depicting rectal prolapse.

Another form of rectal descent is rectal prolapse. When the rectum falls down in the pelvis it can drop so far that it actually drops through the anal opening as a pink fleshy round lump. This is called rectal prolapse.

Rectal prolapse can result in constipation, as it can cause a blockage of the anal opening. The prolapse can stretch the anal sphincter muscles and cause anal leakage (incontinence).

Rectal prolapse is not a cancer and it will not turn into a cancer. Therefore, treatment is necessary only if it is causing a problem.

Symptoms of prolapse which might indicate the need for surgery include persistent bleeding, chronic constipation, difficulty with rectal emptying, straining to move the bowels, mucous drainage, protruding lump, inability to control solid, liquid, or gas bowel movements, or progressive weakening of the anal sphincter muscles.

The aim of the surgery is to remove the extra rectal length and re-suspend the rectum from the lower backbone.

Prolapse can be repaired by either anal surgery or abdominal surgery. In the abdominal surgery, the sigmoid colon is removed and the rectum is sewn to the sacrum (just like the surgery for rectal descent).

Another way to accomplish bowel shortening and re-suspension is to remove the extra rectal length through the anus. Then, the bowel ends are hooked together just above the anus. Removing all the excess bowel leaves the shortened rectum hanging from the inside of the abdomen on the left, by the spleen and ribs. This operation does not require an incision on the front of the abdomen and there is no risk of damage to the nerves of the penis in men.

If a person has rectal prolapse and fecal incontinence (the inability to control bowel movements), fixing the rectal prolapse about half the time also corrects the incontinence. However, if the sphincter muscles are very weak, fixing the prolapse will not correct the incontinence. Additional surgery may be needed to tighten the anal sphincter muscles.

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