A fistula is a disease that develops after a perianal abscess breaks down. One end of the fistula is connected to the primary infected lesion in the anal canal, the internal sinus, and the other end is connected to the perianal skin, the external orifice, mostly formed after a perianal abscess breaks down. The wall of the fistula is formed by the fibrosis of the pus cavity. In Chinese medicine, it is called anal leakage or hemorrhoidal fistula.
The main features are pus and even feces flowing from the anal area and chronic prolongation. This disease is common, the age of onset is mainly 20 to 40 years old, more men than women, infants and children are not uncommon.
Etiology and pathology
According to Western medicine, anal fistula is mostly caused by improper treatment or untimely development of perianal abscess, injury, tuberculosis, tumor and some chronic diseases resulting in immune deficiency can lead to the occurrence of anal fistula.
Infection: perianal infection leads to the occurrence of abscess, although the pus flows out after incision and drainage or self-rupture, but the inner mouth of the infection is still there, feces, bacteria, pus cells, etc. can still enter, resulting in repeated episodes of inflammation, the outer mouth can not be closed, long after the wall of the pus cavity fibrosis, forming a fistula.
injury: trauma, foreign bodies, rough examinations, etc. can damage the rectum of the anal canal and the wound can become infected
tuberculosis: tuberculosis can often be complicated by a tuberculous anal fistula, which may be caused by mycobacterium tuberculosis entering the anal sinus or by bloodstream infection
Immunocompromised: diabetes, leukemia, aplastic anemia, etc., can cause anal fistula by bloodstream infection due to lowered immunity of the body, and pediatric morbidity is also mostly due to immunocompromised.
Other: ulcerative colitis, clonorchiasis, rectosigmoid diverticulitis, lymphogranuloma, radiation bacteriosis, etc. are also associated with anal fistula.
According to Chinese medicine, anal fistula occurs because of external wind, heat, dryness, fire, dampness, diet, constipation, diarrhea, or internal injury to the lungs and spleen, deficiency labor and long coughing. For example, the six books of the river pointed out that “the cover of wind-heat does not disperse, valley flow nourishing, transmitted to the lower part, so that the anus swollen full, knotted like plum kernel, even is turned into a fistula”, “Surgery Dacheng” has “dirty poison …… because of deficiency labor long cough and get The anal nodes must be swollen as chestnuts and broken into fistulas”.
The reason why a perianal abscess cannot heal and form an anal fistula after incision and drainage or self-breaking is the following two reasons.
1, the primary focus is still there: incision and drainage or self-rupture are not solving the internal mouth that is the infected anal sinus, feces, bacteria, pus cells, etc. can still enter and remain, resulting in recurrent inflammation, the external mouth can not heal, the wall of the pus cavity fibrosis formed fistula.
2, poor drainage: repeated infection of the pus cavity wall fibrosis, the formation of curved narrow tube, coupled with the contraction of the sphincter muscle, resulting in drainage of pus does not intestine, fistula tract is difficult to heal, or reroute another penetration of the skin, forming a branch channel.
Classification
There are various ways to classify anal fistulae, the more meaningful ones are as follows.
According to the unified standard classification of the National Conference of Anal Surgery in 1975, the deep line of the external sphincter is used as a marker, and the fistula is high above this line and low below this line, and can be classified as
1, low simple anal fistula: there is only one fistula and it passes below the deep external sphincter with the internal opening in the anal sinus area.
2, low complex anal fistula: fistula below the deep layer of the external sphincter, with more than two external ports, or more than two ducts, with the internal port in the anal sinus area
3, high simple anal fistula: only one fistula that passes above the deep layer of the external sphincter, with the internal orifice at the anal sinus site.
4. high complex anal fistula: there are more than two external orifices, or the duct has branching sinus tracts whose main duct passes above the deep layer of the external sphincter and has one or more internal orifices.
According to the origin of the disease, it can be divided into: purulent anal fistula and tuberculous anal fistula.
The development pattern of anal fistula: draw a horizontal line through the sciatic nodes on both sides of the anus, when the external mouth of the fistula is within 5 cm from the anal verge before the horizontal line, and the internal mouth is at the tooth line opposite to the position of the external mouth, the tube is mostly straight; if the external mouth is beyond 5 cm from the anal verge, or the external mouth is after the horizontal line, and the internal mouth is mostly at the posterior median tooth line, the fistula is mostly curved.
Clinical symptoms
Pus flowing: An ulcerated mouth next to the anus with pus flowing is a typical symptom of anal fistula. The flow of pus can be more or less, and the external mouth can be sealed or ulcerated at times. When the fatigue is too much, the pus increases, and in serious cases, there may be fecal outflow.
Pain: Anal fistula is generally not obvious pain, when the external mouth is closed, or when the pus flow is not smooth, the pressure in the fistula increases, pain, swelling can occur, mostly after the pus flow quickly alleviated or disappeared; also can be due to the large internal mouth, feces into the fistula and pain, especially obvious when defecating.
Pruritus: due to constant stimulation of the skin around the anus by pus, perianal eczema may appear in severe cases.
Systemic symptoms: If the pus does not come out smoothly, there may be fever, chills, loss of appetite, constipation, yellow urine or difficult discharge, and slippery pulse. In cases of recurrent fistula, anemia and emaciation may be seen, and in tuberculous fistula, hot flashes, night sweats, and irritable heat in the heart may be seen.
Diagnosis
In purulent anal fistula, the external opening is small and raised, and the pus is yellowish and thick, with local swelling and pain in the acute stage.
In tuberculous fistula, the external opening is large and depressed, the surrounding skin is dark purple, the pus is thin, and there is septic tissue, and there may be systemic manifestations of tuberculosis.
Low-grade fistulas can be palpated subcutaneously as hard cords, while high-grade or tuberculous fistulas are usually not palpable as obvious cords.
Fistulae are usually not palpable in high grade or tuberculous fistulae. Anal palpation may reveal small raised lumps with central indentation and pressure pain at the corresponding internal orifices.
Anoscopy can reveal an infected sinus at the dentate line with purulent discharge, and the injection of melphalan into the external orifice can help find the internal orifice.
The fistula and the internal opening can be explored by entering the external opening with a probe, but force should not be used to avoid creating a false passage.
Pathological diagnosis can clarify the nature of the fistula, and it has been reported that 10% of fistulas with a history of more than 10 years can become cancerous.
Differential diagnosis
1, purulent sweat glanditis: also known as sweat glanditis, mostly in the distribution area of the sweat glands, such as the perineum, groin, axilla, with multiple ulcers, fistula tracts travel under the skin, involving a wide range, not connected to the rectum.
2, sacrococcygeal tuberculosis: the onset is slow, the ulceration flows clear pus, the ulceration is sunken and does not close after a long time, the symptoms of tuberculosis such as loss of appetite, low fever, night sweats and cough can be seen.
Treatment measures
The treatment of anal fistula is mainly surgical and supplemented by drugs. Drug therapy, mostly used before and after surgery, is used to enhance physical fitness, reduce symptoms, control the development of inflammation, and promote wound healing.
Drug therapy
1.Purulent anal fistula
Symptoms: thick yellow pus, odor, intermittent, accompanied by fever, chills, loss of appetite, constipation, urinary redness, red tongue, yellow greasy coating, smooth pulse.
Treatment: Clearing heat and relieving dampness, detoxifying and subduing swelling.
Remedies: Ermiao San and Dioscorea Z Percolating Dampness Soup plus or minus.
2. Tuberculous anal fistula
Symptoms: thin pus, incessant dripping, accompanied by hot flashes, night sweats, irritability of the five hearts, light red tongue, white greasy coating, thin pulse.
Treatment: Nourish Yin and clear heat, tonify the lung and strengthen the spleen.
Treatment: Nourishing Yin and clearing heat, tonifying the lung and strengthening the spleen.
Surgical treatment
It is possible to cure anal fistula, the key lies in the correct treatment of the internal orifice, the main tube and the branches, and the anal fistula with high involvement of the anorectal ring should be treated properly to avoid causing postoperative fecal incontinence.
1.Hanging wire therapy
Indications: Low-level simple anal fistula with the external opening within 5cm from the anus.
Contraindications: those with skin diseases around the anus; those with fistulas that are still pus-filled; those with severe tuberculosis, syphilis or extreme weakness; those with malignant tumors.
Operation method: take the left lateral position, the patient’s side is under, routine disinfection, local infiltration anesthesia, tie a rubber band at the end of the probe, probe the head of the probe into the external mouth, fistula, the index finger of the other hand into the anus, with the probe to find the internal mouth, and pull out the rubber band through the anus, cut the skin and subcutaneous tissue between the internal and external mouth of the fistula, tighten the rubber band, clamping with hemostatic forceps immediately below the subcutaneous incision, with a ten silk Double ligature, cut the excess rubber band at 1.5 cm outside the ligature line, loosen the hemostatic forceps, fill the wound with comfrey oil sand strips or petroleum jelly gauze, and fix the gauze outside.
Precautions: do not use violence when inserting the probe, so as not to cause false tract; keep the stool open after surgery, daily herbal soup or 1:5000 potassium permanganate solution sitz bath, change medicine; rubber band can generally fall off by itself about 7 days, if it does not fall off after 10 days, it can be cut, if the rubber band is loose, need to tighten the line once again.
2.Cutting therapy
Indications: low simple anal fistula and low complex anal fistula. For high anal fistula, the incision must be combined with wire therapy to avoid anal incontinence.
Contraindications: the same as wire therapy
Operation method: (1) take a lithotomy or lateral position, under lumbar anesthesia or local infiltration anesthesia, routine sterilization and sterile sheeting.
(2) insert a piece of saline gauze into the anus, then inject 1% methylene blue or gentian violet solution through the external opening of the fistula with a blunt-tipped needle syringe, if the gauze is colored, it will help to find the internal opening and facilitate the identification of the fistula during surgery.
(3) Gently insert a slotted probe through the external opening of the fistula, stopping when resistance is encountered, and then cut the skin and subcutaneous tissue and the external wall of the fistula in the direction of the probe, leaving the fistula partially open.
(4) Then insert the slotted probe into the remnant of the fistula and gradually cut the surface tissue of the probe in the same way until the entire fistula is completely cut.
(5) Once the fistula is completely open, scrape out the melanoma-stained necrotic and granulation tissue from the fistula wall with a spatula.
(6) Trim the skin and subcutaneous tissues on both sides of the wound to form a small wound with a wide base to allow for unobstructed drainage, carefully stop the bleeding, and fill the wound with strips of comfrey oil sand or yellow lacquer gauze, padded with gauze and fixed with wide adhesive tape compression.
Precautions during surgery.
(1) If the fistula passes below the anorectal ring, the fistula can be cut all at once. If the fistula passes above the anorectal ring, additional wire therapy must be used. The fistula is first cut in the lower part of the external sphincter, the shallow ring and the fistula below it, and then a rubber band is passed through the remaining tube and led out through the inner port and tied to the anorectal ring, thus avoiding anal incontinence caused by cutting the anorectal ring at once. If the anorectal ring is fibrotic, it can be cut all at once without hanging a thread.
(2) If the fistula passes between the deep and shallow layers of the external sphincter, the two external sphincters should not be cut at the same time when the muscle has not formed fibrosis, and the sphincter should be cut at right angles to the muscle fibers and not at oblique angles.
(3) If a high anal fistula passes through the caudal ligament, a longitudinal cut can be made, but not a transverse cut of the caudal ligament, so as not to cause forward displacement of the anus.
Prevention and rehabilitation
1. pay attention to changing underwear regularly and keeping the skin around the anus clean.
2.Wash with warm water when the skin around the anus is itchy, and avoid scratching with hands to avoid reinfection.