by Fred Licciardi, M.D.
Today we are going to talk more about blockage of the cervical canal: Cervical Stenosis. We will concentrate on the most common causes of cervical stenosis; scaring that results from the treatment of an abnormal pap smear.
Treatment of an abnormal pap can cause scarring of the lower part of the cervix, the external os. This type of scar is a problem for two reasons. First, it reduces the number of mucus producing cells, sometimes lowering natural fertility. Second, it may make fertility procedures, such as insemination or embryo transfer, more difficult.
Most cases of cervical stenosis occur as a result of improper healing from a surgical procedure. It may not be that the procedure was done improperly; it’s just that the healing did not cooperate
It is cells in the area of the external os that are tested during a pap smear. When these cells look abnormal, we need to remove them before they progress to cervical cancer. We treat the abnormal cells by either by destroying them or removing them: both processes can cause scarring. Examples of destroying the tissue include cauterization (basically burning away with electricity or a laser) and cryo.
Cautery just basically fries the cells away, some abnormal and some normal tissue. Cryo literally freezes off some of the tissue of the external os, removing abnormally growing cells and some normal tissue. Cryo and cautery are not popular because they do not give you any tissue to send to the lab.
Rather than destroying cervical tissue, there are other procedures that remove a small piece. Examples of tissue removal include a cone biopsy or a LEEP (Loop Electrosurgical Excision Procedure). The cone procedure and LEEP are basically the same thing, however if necessary the LEEP can be a little more precise and remove a smaller amount of normal tissue. The LEEP and the cone biopsy cut away pieces of tissue that can be further evaluated under the microscope.
A cone involves and old fashioned scalpel, and takes away a larger piece in the shape of a cone (pictures to follow). The LEEP uses a thin wire loop that scoops out a little piece. However, sometimes using a LEEP the doctor needs to take a larger area as if a cone were being performed. Today, most procedures are LEEP procedures because the biopsy can be directed; in other words, only a small area can be removed if necessary. In addition, the LEEP can be performed in the office as opposed to the hospital. Finally, there is a lower chance of bleeding with a LEEP.
No matter which of these procedures is performed, a small percentage of people can have post-op scarring that leads to cervical stenosis. The more tissue removed or destroyed, the greater the chance of a scar.
Why do some people scar an others not? Some people are just more prone to it. Scaring is the normal way we heal. For some women, the scarring is more robust and progresses enough to cover over the cervical canal. Certainly, if any of these procedures are followed by infection, scarring will be more likely.
Let’s go through the pictures.
Here is our uterine drawing showing the uterus and cervix. 
The next picture is a drawing of what your doctor sees when she puts in the speculum. It’s the cervix, actually the very bottom of the cervix. 
Let’s say your pap comes back abnormal. This usually means that there are some cells around the external os that are abnormal. Depending on the severity of the pap, these cells may need to be removed. Using some special techniques, you doctor would look very carefully at your cervix under magnification to try to determine the extent and location of the abnormality.
This picture is an example of abnormal cells in a very small area. 
Here, the doctor does not need to remove much tissue, and this is not likely to lead to scarring. The doctor will probably use the LEEP procedure, but only a small amount of cervix needs to be removed. This picture shows a cervix with a small abnormality and a small LEEP. 
This picture shows a case where there is a larger amount abnormal cells and they take up a larger area on the cervix. 
In this case, the abnormal cells are all around the external os. Here, the doctor needs to take away much more tissue. 
You can see that the shape of the removed tissue is in the shape of a cone, thus the term cone biopsy. A larger LEEP will also make a cone shaped biopsy. While the odds of scaring remain low, if it does happen, it is more likely to come from taking more tissue. The next picture shows a post-LEEP scar. 
The good news is that in most cases, scarring at the external os is the easiest to deal with. Unlike scar tissue that forms higher up in the cervix, scarring at the external os can be seen with a speculum and the scar is usually shallow. The scar is usually on the thin side and can be easily opened, usually in the office.
After opening, the scar may have a tendency to return, but re-opening is not that difficult. In the case of fertility treatments such as insemination and embryo transfer, the scar can be opened just prior to these procedures without much difficulty. Unfortunately some women can have more serious scarring after these procedures that is not so easy to deal with. Additionally, some women need to have multiple biopsies, and this will increase the scar risk.
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