Rectal fistula

Rectal fistula, or fistula ani in Latin, is an abnormal hollow passage that forms between the inner surface of the rectum and the skin near the anus.
In 90% of fistulas, the cause is a blockage or inflammation of the glands that open into the rectum.
These glands are located in the space between the inner and outer sphincter rings of the rectum.
The pus that forms during the inflammation tries to leave and make its way into the tissues adjacent to the rectum.
In the vast majority of cases, a rectal abscess develops first, which in 40-50% of patients will subsequently heal by leaving a fistula behind.
Sometimes the inflammation of the glands does not lead to abscess formation, but the chronic condition, rectal abscess, develops straight away.
Rectal abscess and rectal fistula are therefore two different manifestations of the same disease, acute and chronic complications of inflammation of the glands that open into the rectum.
In the remaining 10% of fistulas, the underlying cause is not inflammation of the glands but other diseases such as inflammatory bowel disease (Crohn’s disease), sexually transmitted diseases, trauma, cancer or radiotherapy.

The classic symptom of rectal fistula is a purulent, bloody, foul-smelling discharge around the anus, often accompanied by skin irritation and itching.
If the duct becomes inflamed, there is discomfort and pain around the anus, mainly during sitting and defecation.
If the pus cannot be drained during the inflammation, an anal abscess develops, which is accompanied by constant throbbing, tightening pain, sometimes fever, and requires urgent surgical intervention.

Rectal bulbs are classified according to their course, i.e. where the duct is located in relation to the outer and inner sphincter rings of the rectum.
On this basis, the following types are distinguished: Submucosal: The fistula duct is superficial, runs under the mucosa, and does not pierce the muscle fibres of the sphincter apparatus. Intermuscular sphincter: The fistula passage pierces the internal sphincter and runs down to the skin between the external and internal sphincter.
The external sphincter remains intact in this case. Sphincter piercing: The fistula passage pierces both the external and internal sphincter rings. Above sphincter: A high arching fistula passage that pierces the internal sphincter, then passes high between the external and internal sphincter rings, pierces the puborectalis muscle and then turns downwards to the skin adjacent to the rectum. External sphincter: Highly arcuate fistulous duct that bypasses the entire sphincter apparatus from the outside, pierces the pelvic floor and opens high into the rectum.

The diagnosis of rectal polyps is usually clear from the patient’s history and complaints and the physical examination.
During the physical examination, the doctor first locates the external orifice of the fistula duct and from there, using a thin probe, tries to identify the course of the duct and its internal orifice.
In our clinic, the examination is always complemented by a 3D rectal ultrasound scan, which allows us to precisely map and visualise the course of the fistula and its position in relation to the sphincter rings of the rectum.

Unfortunately, rectal abscesses rarely heal on their own, so medical intervention is required in virtually all cases.
Therapy depends on the course of the fistula, the sphincter involved, the complexity of the duct and any underlying disease (e.g. Crohn’s disease).
Very superficial fistula passages with no or minimal sphincter fibre can be operated on an outpatient basis, and the passage can simply be ruptured.
In all other cases, where the fistula runs higher, the operation is performed in two steps, on two separate occasions.
In the first step, the fistula is inserted into the fistula in a so-called “second step”.
The first step is to tie a seton thread into the fistula, which is then left in place for several months (usually 3 months).
This does not cause the patient any discomfort or discomfort.
During this time, the side branches of the duct are closed, the inflammatory process calms down, the wall of the main fistula duct becomes thicker and harder, allowing the surgeon to prepare the duct more effectively for the second operation, with better chances of healing.
During the second operation, our surgeons always choose the most suitable surgery for the patient to eradicate and close the fistula.