How is anal fistula formed

Speaking of anal fistula, it is a very common anorectal disease in daily life. Of course, there are also many people who do not understand what anal fistula is, but the high-risk group for anal fistula is young and middle-aged people. This part of the population happens to be in the period of working hard for their careers and earning money to support their families. Once you don’t pay attention to it, if you get anal fistula, it will have a considerable impact on your life and work, because this anal fistula will not heal itself and must be treated surgically. Moreover, due to infection, it may cause inconvenience in excretion, and pus may stain clothes after infection, and it may also produce some odor, which makes people miserable. Early treatment of anal fistula is the most correct choice. So how is anal fistula formed? Let’s talk about this issue below.

Most anal fistulas are formed after an anorectal abscess ruptures or pus is drained after incision. The abscess gradually shrinks, but intestinal contents continue to enter the abscess cavity. During the healing and shrinking process, a tortuous cavity is often formed, which makes drainage poor and difficult to heal. After a long time, there is a lot of scar tissue around the cavity, forming a chronic infectious tract. It runs near the internal and external sphincters, and the skin of the external opening grows faster, often with pseudo-healing properties, causing repeated attacks. Most duct infections are purulent, and a few are tuberculous.

1. The rupture or incision of anorectal abscesses usually occurs outside the anus, with pus flowing out from the external opening, but the primary infection usually occurs in the anal sinus. The anal sinus is the gateway for secondary infection, and repeated infection can form a fistula.

2. Fistulas often pass between the anal sphincters. Because the sphincters constantly contract and relax, they compress the fistulas, affecting the discharge of pus, making it easy for pus to accumulate and become infected, making it difficult to heal.

3. There is a certain pressure in the rectum, and rectal infected substances such as feces and gas can often enter the fistula from the internal opening, irritate the cavity wall, and be discharged from the external opening after secondary infection, which is also the cause of the fistula.

4. After the anorectal abscess ruptures, the pus is discharged, the abscess cavity gradually shrinks, the external rupture opening and incision also shrink, and the cavity wall forms a hard tubular wall of connective tissue hyperplasia, so it cannot close naturally.

5. The fistula tract is tortuous or has sinuses or branches, resulting in poor drainage, pus retention, and repeated infections, making the fistula tract difficult to heal.

6. The anal venous return is poor, local congestion often occurs, tissue malnutrition occurs, and healing is affected.

7. Abscesses caused by infections such as Mycobacterium tuberculosis, Actinomycetes, and Crohn's disease are difficult to heal on their own and form special anal fistulas.