What Is an Anal Fistula?

Anal fistula is an abbreviation of anorectal fistula, which is a sequelae of abscess ulceration or drainage of incision around the anorectum. Anal fistula is the post-abscess era and is two stages of a disease. English name Anal fistula, Chinese medicine is called anal leakage. A typical anal fistula is an open and complete tube, one in the anal sinus, the other outside the anal margin, or the rectal wall. Atypical anal fistula generally has only an inner mouth and no outer mouth, or although there is an inner mouth and an outer mouth, but the middle fistula is occluded, or there is only the outer mouth, the inner mouth is not found, or there is only a single induration.

Basic Information

nickname: Anal leakage
English name: anal fistula
Visiting department: Anorectal
Multiple groups: 20 to 40 year olds, male infants

Common causes: Perianal abscess, rectal anus injury, repeated anal fissure infection and other factors
Common symptoms: Repeated discharge of pus from the outer mouth, contaminating underwear; sometimes itching

Anal fistula epidemiology

Anal fistula accounts for the incidence of anorectal disease, which is 1.67% to 2.6% in domestic statistics and 8% to 20% in foreign countries. The age of onset is mainly 20 to 40 years old. Infants and young children are also not uncommon, mainly in boys, girls are rare, the ratio of boys to girls is 5: 1.

Causes of anal fistula

Perianal abscess

Perianal abscess is caused by ulceration or incision and drainage.

2. rectal and anal injury

Traumatic injuries, swallowing bones, metals, anal thermometers, anoscopy and other anal canal injuries can be caused by bacteria invading the wound.

3. Repeated infection of anal fissure

Repeated infection of anal fissure can be complicated by subcutaneous fistula.

4. Perineal Surgery

Injection of internal hemorrhoids into the muscle layer or infection after surgery, postpartum perineal suture infection, infection of the prostate and urethra after surgery, etc., can affect the anorectum and cause abscesses and fistulas.

5. Tuberculosis

There have been many reports of tuberculosis complicated by tuberculous anal fistula. It is as high as 26.9%, which has decreased significantly to 4% to 10% in recent years. Mainly caused by swallowing tuberculosis bacteria, a few can also be caused by bloodstream infections.

6. Ulcerative colitis

7. Crohn's Disease

Crohn's disease is associated with anal fistula as high as 14% to 76%.

8. rectal anal canal cancer

Rectal anal canal cancer spreads to deep and complicated with anal fistula.

9. Hematogenous infections

Diabetes, leukemia, aplastic anemia and other diseases, due to reduced body resistance, often caused by bloodstream infections anal fistula.

10. Other

Lymphogranuloma, actinomycosis, cercaria osteomyelitis, rectum and sigmoid diverticulitis can also cause anorectal abscesses and fistulas.

Clinical manifestations of anal fistula

Pus

Periodic attacks, sometimes absent, with less pus.

Swelling and pain

Generally, it is not painful. When the pus is accumulated in the lumen and the drainage is not smooth, the pain is localized. When the pus flows out, the pain is relieved immediately.

3. Lump

Most patients can touch a cable-like lump at the edge of the anus, and the pain is mild.

4. Itching

Pus often irritates the skin around the fistula, causing itching or eczema on the anal skin.

5. Systemic symptoms

(1) Generally without systemic symptoms .

(2) Complex or prolonged periods of time . Symptoms such as difficulty in defecation, narrowness, anemia, physical wasting, mental weakness, neurasthenia, etc.

(3 ) There are systemic symptoms such as elevated body temperature during different infections .

Anal fistula classification

Anal fistulas are complex and need to be further subdivided. Many classification schemes are given at home and abroad. Here are the most commonly used classification methods in clinical practice.

High low

In 1934, Millgan and Morgan of S.mark Hospital in England used the tooth line as the dividing line. This division method is simple and clear, and has strong practicality. The dental floss is the dividing line between the anus and the rectum and can be clearly seen under anoscope. The anal sinus at the tooth line is the infected inner mouth of the anal fistula. Taking this line as the starting point, the upper anal fistula is the upward, and the lower anal fistula is the lower.

In 1975, the domestic anorectal community held the first national anorectal conference in China's history in Hengshui City, Hebei Province. At this meeting, it was determined that the deep part of the external anal sphincter is the high and low dividing line.

2. Single fistula and multiple fistula

There are only one external fistula or multiple fistulas, which are called simple anal fistulas. If there are multiple fistulas, they are called complex anal fistulas. However, some fistulas are too long or curved, which can also be clinically called complex anal fistula. Complex anal fistula is sometimes a single internal mouth, and there are multiple internal mouths, which must be distinguished because clinical treatment methods are different. This classification method was proposed by Chinese scholars at the Hengshui Anorectal Conference in 1975 and is currently widely used clinically.

3. Subcutaneous mucosa

Most anal fistulas pass through the anal sphincter, with the exception of the subcutaneous mucosal anal fistula. These are the two superficial types of anal fistula, which are basically located inside the sphincter. The subcutaneous fistula located under the anal margin is called subcutaneous fistula. It is very close to the anal margin, generally not more than 5cm, and the inner mouth is located at the tooth line corresponding to the outer mouth. The submucosal anal fistula is located under the rectal mucosa, and the inner mouth is located at the same line of teeth.

Anal fistula examination

Anal fistula is difficult to treat, first of all, it is difficult to diagnose. Only the position of the fistula and the position of the inner mouth can be provided before the operation to provide the most powerful guarantee for the success of the operation. There are two ways to locate the inner mouth, directly to find and to find the fistula. Only a few cases can be found directly. During digital anal examination, the hard joint or depression can be touched at the tooth line of the anus, or pus can flow out when pressing the fistula. In most cases, the inner mouth is concealed or closed, which requires finding a fistula or outer mouth, and then following the vine. There are six methods: see, touch, explore, pour, look, and cut. These methods are for different fistulas, and each has a range of adaptation. Sometimes one method can be found, and sometimes several kinds of cooperation are needed.

Look at

First divide the anus into two parts, the outer mouth is in the second half, and the inner mouth is basically at 6 o'clock (rear center). The outer mouth is in the first half. There are two cases. The outer mouth is within 5cm of the anal margin, and the inner mouth is at the tooth line corresponding to the outer mouth. If the outer mouth is more than 5cm from the anal margin, the inner mouth will wrap around 6 o'clock on the back side. The accuracy of this law is about 80%, which is generally used as a preliminary judgment before other inspections.

Touch

Refers to the diagnosis. General anal fistula can be diagnosed by "touch". However, if the fistula is deep, or is not completely formed, or belongs to the sphincter, then the following measures need to be taken to continue the examination.

3. explore

Use the probe to enter from the outer mouth of the anal fistula. As long as the fistula is unobstructed, the probe can always reach the inner mouth. During the operation, the fistula is cut open along the probe. The use of a probe to locate the inner mouth requires the exclusion of two conditions: occlusion in the middle of the fistula does not work, and fistula does not work.

4. irrigation

For curved fistulas, you can't touch it, nor can the probe. At this time, you need to inject liquid from the outer mouth to see where it flows out, and the outflow is the inner mouth. The liquids used are Meilan and hydrogen peroxide. The prerequisite for using this method is that the fistula is open.

5. Photo

B-ultrasound, X-ray, CT, and magnetic resonance examinations are all in the category of "photograph", especially B-ultrasound, which has been widely used in clinical practice in recent years. Some experienced doctors can accurately describe the location and scope of fistulas. The relationship with the sphincter and the position of the inner mouth. It has important reference value for deep fistula, CT and magnetic resonance examination. It should be pointed out that these physical examinations can only provide a reference, because in the end, the lesion must be touched by hand before surgery.

6. cut

In the case that the inner mouth cannot be located by the above methods, the fistula can only be opened, and the scar and necrotic tissue can be cut and searched.

Anal fistula treatment

Drug treatment

Anal fistulas have intermittent and seizure periods. There will be no symptoms at all during the interim period, and you can take no medicine at this time. Symptoms such as pus, redness, swelling, and pain appear during the attack. If surgery cannot be performed immediately, medication can also be used to temporarily relieve the symptoms.

(1) External treatment Sit down with an anti-tumor analgesic lotion and apply golden cream on the outside.

(2) Use of antibiotics Antibiotics can be used during acute attacks, but generally not more than one week.

(3) Oral administration of traditional Chinese medicine. Add and subtract the detoxification and detoxification decoction with osmotic infiltration and detoxification soup.

2. Surgical treatment

(1) Incision and drainage Anal fistula is complicated by infection. At this time, due to other factors in the body, surgery can not be performed. You can cut a small orifice on the surface of the infection or drain the pus with a syringe. The effect of this method is immediate, but it is only temporarily relieved, and radical surgery is needed in the future.

(2) Intubation or drainage for complicated fistula of high fistula or multiple fistulas, there is no certainty of surgery, but in order to prevent the disease from aggravating or spreading, a drainage tube or drainage strip can be placed in the fistula, and the drug is flushed daily. But the condition can be controlled.

(3) Anal fistula incision The most classic and mainstream anal fistula, more than 90% of low anal fistulas are treated with this method.

(4) Fistula Removal The fistula is completely adhering and the thin lower anal fistula cannot be penetrated by the probe, so it can be removed.

(5) Dissection of the main fossa tube is applicable to various complicated anal fistulas. The first step is to locate the main focus and the fistula at the inner mouth and anal canal. This part is taken directly. Expansion of foreign trade. Open the fistula between the outer mouth and the main focus, and place a drainage bar or drainage tube. Removed about 7-10 days after surgery.

(6) Suture technique is suitable for high anal fistula. Suture is the main method for treating high anal fistula at home and abroad. Using a cutting knife to perform slow cutting can cut the anal fistula wall and cause inflammatory adhesion at the stump to prevent retraction. It can properly protect the function of the anus. But the disadvantage is that the pain is obvious, especially the secondary tight line is needed, and the course of treatment is relatively long.

(7) Two-way isobaric drainage is suitable for high anal fistula and complex anal fistula. Adopting a half-cut hanging thread can effectively protect the core structure of the anal canal from the "anal straight ring" during surgery, which can effectively protect the anal function from being damaged while ensuring the efficacy.

(8) Fistula Packing Considering that both the incision and removal will disconnect the anal sphincter that the fistula passes through, domestic and foreign attempts to use some special materials to fill the fistula can heal the anal fistula without hurting the anal muscles. These materials include fibrin glue, biorepair plugs made from lyophilized porcine small intestinal submucosal acellular matrix. The application conditions of this method are very harsh, low fistula with complete, unobstructed fistula and clear internal and external mouth. If the tamponade leaks or becomes infected, the treatment will fail. At present, it cannot be widely used in clinic as an alternative therapy.

(9) Lift operation This method was proposed by Arun et al. In 2007, and its full name is 1igationofintersphinctericfistulatract, which means "intersphincteric ligation of the sphincter", which can be used for the treatment of low fistula. The advantage is that it does not open the fistula, but the cure rate is low. As an exploration of the anus-preserving technique, the success rate reported in the literature is 14% to 60% because there is no risk of anal incontinence.

(10) VSD negative pressure closed drainage technology Negative pressure closed drainage technology (VSD) is a new method for dealing with various complex wounds and for deep drainage. In recent years, many scholars at home and abroad have applied it to the treatment of various acute and chronic complex wounds and achieved good results. In recent years, some units in the anorectal department have begun to apply, and the effect needs to be further verified. The treatment of high anal fistula needs more exploration. VSD technology has achieved good results in other surgical fields. It can be tried in high anal fistula and large-scale perianal abscess treatment. The disadvantage is that the patient's movement is limited, and the anus has to have bowel movements, which have set a barrier for the application of the technology in the anorectal department.

Prognosis of anal fistula

1. Anal fistula can be cured after surgery.

2. For high complex anal leakage, the internal mouth is not clear during the operation and there are many branches, there may be recurrence after operation. In some patients, anal sphincter damage may cause abnormal stool control during surgery.

3. Patients with diabetes, leukemia, clonal disease, ulcerative colitis and other diseases need to actively treat the primary disease at the same time.

4. There is still a risk of canceration in the anal fistula that has not been cured for a long time.

Anal fistula prevention

1. Prevention and treatment of constipation and diarrhea are of great significance in preventing the formation of perianal abscess and 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, regular defecation, take a bath after defecation daily, and keep the anus clean, which has a positive effect on preventing infection. ^[1-2]

References

[3] Xu Mengting, Chen Fujun. Diagnosis status of anal fistula [J]. Modern Journal of Integrated Traditional Chinese and Western Medicine, 2009, 08 ": 36-938.

[4] Zhang Yiwen. Comparison of curative effect of low incision and high hanging solid and virtual hanging therapy on high anal fistula [J]. Frontiers of Chinese Medicine, 2013, 24: 37-38.

[5] Wu Ke, Zhao Haoxiang. Recent diagnosis and treatment of anal fistula in traditional Chinese and western medicine [J]. Modern Journal of Integrated Traditional Chinese and Western Medicine, 2010, 01: 123-126.

[6] Tian Zhenguo, Han Bao. The theory and practice of anorectal bowel in traditional Chinese medicine [M]. Beijing. Chinese Medicine Ancient Borrow Press, 2013: 430-433.