Causes
The most frequent cause of fistulas of the anus are smaller abscesses in the area of the so-called anal crypts. Crypts must be imagined as small indentations of the mucous membrane. Depending on their location, these abscesses can then break into the proctodeal glands mentioned above.
Depending on the location of the glands, different parts of the mucosa as well as the inner and outer sphincter muscle are affected. If this abscess empties spontaneously or through a surgical opening to the outside or inside, an anal fistula develops. It is possible that the skin of the anus will then show the ducts of these fistulas.
However, they can also be located on the side of the mucous membrane (inside). Other causes of anal fistulas are inflammatory bowel diseases. However, these are far less common causes. These diseases include Crohn’s disease, ulcerative colitis, diverticulitis and cryptitis. Cancer of the gastrointestinal tract also probably plays a role in the development of anal fistulas.
Symptoms
The detection of a fistula is done by inspection, palpation (palpation with digital-rectal examination) and rectoscopy (endoscopy of the rectum). During inspection, it can be difficult to find the anal fistula. Usually a small excretory duct is visible, which is slightly below the level of the skin.
In some cases it can only be found by spreading the anal skin. However, a fistula can also look like a small wart, where secretion or pus is released by pressure. An MRI of the pelvic floor can be helpful to find the internal and external fistula duct (especially in complex cases).
The so-called probing is also used to gain a more precise insight into the spatial conditions of the fistula. A probe is inserted into the fistula. The differential diagnosis of anal fistula is to be distinguished from perianal thrombosis or hemorrhoidal prolapse.
If you suspect that you have a fistula in your anus, it is best to consult your own family doctor first. This doctor can usually confirm the suspicion and make the diagnosis. In addition, he or she will issue a referral for the responsible specialist.
In the case of an anal fistula, a proctologist or a surgeon should be consulted. Fistulas are often treated in surgical centers where doctors work with the additional title “proctology”. This subspecialty deals more closely with diseases of the rectum, the rectum and the anal canal.
A dermatologist is also the right person to contact first, as he too can recognize a fistula in the anus and make suggestions for further procedures. The therapy of a fistula is carried out surgically, since spontaneous healing does not actually occur. Various procedures are used.
The fistula is split in this procedure. The tissue that lies between the fistula duct and the anal canal is cut through. Various probes are used, which are placed in the fistula tract.
Especially superficial fistulas can thus be treated very well and almost completely without recurrence or complications. Nevertheless, continence disorders may occur postoperatively, which are a serious complication. The more material is cut through the sphincter muscle, the higher the risk of this after-effect.
The procedure can be performed under local anesthesia. The opened fistula is then left to open wound healing. Spring drainage is also a frequently used procedure in the treatment of anal fistulas.
Various sutures and techniques are used. The aim of this procedure is to drain the pus from the fistula. It is used, for example, before plastic fistula closure or if the risk of cutting out a fistula is too high.
The first technique is called “loose spring drainage”. Its aim is to drain the pus in the long term and prevent closure of the external fistula opening. After removing the suture, the fistula is left to heal spontaneously.
The second procedure is the fibrosing suture. The aim is to fibrotize the fistula duct. Fibrosis is the transformation of the organ tissue into connective tissue, the fistula is thereby quasi “drained”.
The procedure is associated with a certain risk of continence disorders. It is mainly used for high fistulas prior to plastic reconstruction. The last procedure is called “Cutting Seton” or also “cutting suture”.
According to recent studies, this procedure has an unacceptably high risk of continence disorders and is therefore no longer recommended. The aim of the procedure is to cut through the sphincter parts lying in front of the fistula duct and to clear the purulent area. Plastic closure of an anal fistula is used when radical removal of the fistula is not possible due to an unfavorable position or size.
There are 5 different procedures, but they have basically the same aim and are similar in principle. The inner fistula opening (inner ostium) is closed with a suture in the rectum. It is then stabilized with a tissue flap of different origin.
It is also possible to close the inner fistula opening without additional tissue flap. Plastic surgery is an established treatment option with a chance of healing of 60-80%. They do not differ significantly in their healing rate, but they have different risks of complications about which the patient must be informed.Here the fistula tract is first cleared out and then filled up with a fibrin glue.
The fibrin glue is a biological product. Fibrin is a protein that plays an important role in blood clotting. This procedure is usually only used in special cases.
The anal fistula plug is also a biological product made from small intestine components of the pig. It is used to close the fistula and also serves as a growth base for the body’s own tissue, so that it is gradually replaced by it. It represents another treatment option for high fistulas. The fistula is destroyed and closed by heat.
