Simple anal fistula means that the skin beside the anus has only one external opening. Those who pass directly to the inner mouth of the anal recess on the tooth line are called internal and external fistulas, also called complete fistulas; if there is only an external mouth but no internal mouth, it is called an external anal fistula, also called an external blind fistula; if only the internal mouth is connected to the fistula , And there is no external opening, called internal anal fistula, also called internal blind fistula.
Simple anal fistula is the most common type of anal fistula, which can be divided into low simple anal fistula and high simple anal fistula. Low simple anal fistula is a complete fistula with only one fistula, one internal opening and one external opening. The internal opening is at the dentate line, and the duct passes through the superficial part or below the external sphincter; the internal opening of the low complicated anal fistula is at the dentate line. The duct is below the deep layer of the external sphincter, with branches and cavities, and two or more external ports and ducts. The disease can occur in all ages and different genders, and it is more common in young men.
1. Perianal abscess
Perianal abscess is caused by spontaneous ulceration or incision and drainage.
2. Rectal and anal injury
Trauma, swallowing bones, metal, anal thermometer, anoscopy and other damage to the anal canal and rectum, bacteria can invade the wound.
3. Hemorrhoids, anal fissure surgery
Local infection after hemorrhoids and anal fissure surgery results in a simple anal fistula. In addition, repeated infections of anal fissure are prone to complicated by subcutaneous fistula.
4. Perineal surgery
Internal hemorrhoid injection into the muscle layer by mistake or infection after surgery, infection after postpartum perineum suture, infection after prostate and urethral surgery, etc., can spread to the anorectum and cause abscesses and fistulas.
In the past, many cases of tuberculosis complicated by tuberculosis anal fistula have been reported, as high as 26.9%, but in recent years it has dropped significantly to 4%-10%. Mainly caused by swallowing Mycobacterium tuberculosis, a few can also be caused by blood infection.
6. Ulcerative colitis
7. Crohn's disease
As many as 14% to 76% of Crohn's disease with anal fistula.
8. Rectal and anal canal cancer
Rectal and anal canal cancer spreads to the deep part with anal fistula.
9. Blood infection
Diabetes, leukemia, aplastic anemia and other diseases are often caused by anal fistula due to the decrease of body resistance.
Lymphogranuloma, actinomycosis, coccosacral osteomyelitis, rectal and sigmoid diverticulitis can also cause anorectal abscess and fistula.
Intermittent or continuous discharge of pus from the anus.
2. Swelling and pain
-Normally no pain, only feel the anal mouth swelling or falling pain, when the pus drains smoothly, the swelling and pain will be relieved immediately. Sometimes pain can be caused by the large internal mouth and the feces flowing into the pipe, especially when the pain is aggravated during defecation.
The continuous outflow of pus or secretions stimulates the perianal skin and causes dampness and itching, sometimes accompanied by perianal eczema.
4. Systemic symptoms
Simple low anal fistula generally has no systemic symptoms. High simple anal fistula can be accompanied by systemic symptoms such as fever and chills when pus accumulates in the acute stage.
Visible rupture of the outer mouth, induration can be palpable if the outer mouth is closed. Sometimes when pressing the fistula, secretions may overflow from the outer mouth.
You can understand the depth of the fistula tube, the direction and the position of the internal opening by touching it. Low-position simple anal fistulas are easier to touch with rigid cords, and the touchable cords lead to the anus.
The main observation is whether the anal crypts have hyperemia, depression, and discharge. During the treatment, the probe can be used to check the position of the inner mouth.
4. Dyeing inspection
Place a piece of dry gauze inside the anus and inject the methylene blue solution from the outer mouth. If the inner mouth is not closed, the gauze will be colored, which can help find the position of the inner mouth.
5. X-ray inspection
Inject 30%-40% of lipiodol from the external opening of the anal fistula. The distribution of the fistula can be seen in the photograph, which can show the condition of the high anal fistula.
6. Intra-anal ultrasound
It is of high diagnostic value to clarify the relationship between the scope of the simple anal fistula and the sphincter.
Anal fistula often has a history of spontaneous ulceration or incision and drainage of the perirectal abscess of the anal canal. After that, the wound does not heal for a long time and becomes the external opening of the anal fistula.
(1) Drug treatment
Simple anal fistulas cannot heal by themselves and require surgical treatment, but medical treatment is a necessary method for auxiliary surgical treatment. When symptoms such as pus, redness, swelling, and pain appear during the attack, medication can be used to temporarily relieve the symptoms.
1. External treatment
Take a bath with a lotion that promotes blood circulation, reduces swelling and relieves pain, and coats with golden cream.
2. Use antibiotics
Antibiotics can be used during acute attacks, but generally do not use more than a week. Syndrome differentiation, treatment, can be used 萆薢shenshi decoction plus Huadu dehumidification decoction, and those with fever can use Xianfang Huoxing Decoction.
(2) Surgical treatment
Some patients may experience temporary or transient closure of the fistula after drug treatment, which will recur after certain incentives, such as spicy food stimulation, overwork, imbalance of intestinal flora, decreased body resistance and abnormal autoimmune function Wait. Therefore, surgery is the most effective way to cure simple anal fistula. Commonly used clinical surgical methods include:
It is suitable for the common low-position simple anal fistula in clinical practice. The surgical method is to use a probe to find out the direction of the fistula and the position of the internal opening, open the fistula all at once, remove the fistula wall and necrotic tissue, trim the wound edge, and drain the flow smoothly. This method of surgery will not damage the anal straight ring, is safe and effective, and has a high cure rate.
2. Low-cut high-hanging method
It is suitable for high-position simple anal fistula, which is a classic method that has been used clinically. Its characteristic is that the part below the anorectal ring is directly incised, while the part above the anorectal ring is threaded. Although this method may damage part of the sphincter and occasionally have abnormal defecation, the cure rate is relatively high. Most high-position simple anal fistulas can be completely cured, and the clinical application has a definite effect.
1. Postoperative complications such as urinary retention, bleeding, pain, etc. may exist after simple anal fistula, which requires timely symptomatic treatment.
2. Some high-position patients with simple anal fistula may have anal deformities, even air leakage, and stool leakage when the anal sphincter is injured during surgery.
3. Patients with diabetes, leukemia, Crohn's disease, ulcerative colitis and other diseases need to actively treat the primary disease at the same time.
4. Anal fistula that has been cured for a long time still has the risk of cancer.
1. Reasonable diet, balanced nutrition, prevention and treatment of constipation and diarrhea, and avoiding the occurrence of intestinal flora imbalance are of great significance for preventing the formation of anal fistula.
2. Treat anal cryptitis and anal papillitis in time to avoid the development of perianal abscess and anal fistula.
3. Develop good living habits, defecate regularly, take a bath after defecation every day, and keep the anus clean, which has a positive effect on preventing infection.
Department of Anorectal, Tongchuan District Hospital of Traditional Chinese Medicine, Dazhou City