Anal fistula resection

Anal fistula mainly invades the anal canal, rarely involves the rectum, and is an infectious duct that communicates with the perianal skin. The inner mouth is located near the tooth line, and the outer mouth is located on the perianal skin. It is a common disease in anal canal and rectal diseases. There are many classification methods for anal fistula, but it is not only related to the location of the abscess around the anorectal rectum, the relationship between the fistula and the anal sphincter. At present, the anal fistula is divided into four categories according to the relationship between the fistula and the sphincter. 1 sphincter anal fistula: mostly low anal fistula, the most common, accounting for about 70%, is the consequence of abscess around the anal canal. The fistula only passes through the internal sphincter, and there is usually only one outer mouth, which is closer to the anal margin, about 3 to 5 cm. A small number of fistulas are up, forming a blind end between the rectal ring muscle and the longitudinal muscles or penetrating into the rectum to form a high sphincter spasm. 2 sphincter anal fistula: can be low or high anal fistula, accounting for about 25%, is the consequence of the ischial rectal abscess. The fistula passes through the internal sphincter, between the superficial and deep parts of the external sphincter, and there are often several external ports, and the branches communicate with each other. The outer mouth is closer to the anal margin, about 5cm, and a few fistulas pass up through the levator ani muscle to the connective tissue adjacent to the rectum, forming a pelvic rectal fistula. 3 sphincter anal fistula: high anal fistula, rare, accounting for 5%. The fistula passes up the levator ani muscle and then penetrates the skin down to the ischial rectal fossa. Because the fistula often involves the anorectal ring, it is difficult to treat and requires staged surgery. 4 sphincter anal fistula: the least seen, accounting for 1%, for the consequences of pelvic rectal abscess combined with sciatic rectal abscess. The fistula communicates with the rectum through the levator ani muscle. This anal fistula is often caused by Crohn's disease, colon cancer or trauma, and treatment should pay attention to its primary lesion. The above classification is more detailed in the high and low positions, which is conducive to the choice of surgical methods. Clinically, the anal fistula is often divided into two categories: low or high. The former is below the anorectal ring and the latter is above the anorectal ring. There are also an anal fistula from the shape of the fistula, which is divided into straight, curved and hoof-shaped anus. Straight sputum is often a low anal fistula, and the hoof-shaped anal fistula is often high, and the flexion can be low or high. From the pathological changes, it can be divided into suppurative anal fistula and anal fistula caused by specific infection. Anal fistula can not heal itself and must be treated surgically. The principle of surgical treatment is to cut all the fistulas and, if necessary, remove the scar tissue around the fistula, and gradually heal the wound from the base. Anal fistula is different from incision in that the fistula is completely removed to healthy tissue. Treatment of diseases: anal fistula Indication Anal fistula is suitable for: 1. The duct is more fibrotic than the simple and complex anal fistula, and the direction of the pipeline is below the anorectal ring. 2. Cooperate with hanging line therapy to treat high anal fistula. Contraindications High anal fistula should not be resected. Preoperative preparation 1. Complexity or high anal fistula should be done with 40% iodized oil. The method is: first enema with warm saline, drain the stool, and take a bath once. Place a metal sign on the anal and outer mouth. Use a contrast needle (use an epidural needle or a small puncture needle to remove the head) and insert it from the outer mouth. The pipeline was washed with 3% hydrogen peroxide and saline to increase the success rate of the contrast. Then, the contrast agent was injected under the X-ray fluoroscopy to observe the trend of the contrast agent, and the positive and lateral positions were taken. 2. Shave the skin around the anus. 3. Give fluid to the body 1d before surgery. 4. If necessary, do soapy water enema 4 to 6 hours before surgery. Surgical procedure 1. After injecting 1% methylene blue or methyl violet from the outer mouth of the fistula, the operator inserts the index into the rectum as a guiding marker, and then gently inserts it from the outer mouth with a bendable blunt probe and pierces through the inner mouth. 2. Clamp the skin of the outer mouth with the tissue forceps, cut the skin and subcutaneous tissue around the outer mouth of the fistula, and then cut off the skin, subcutaneous tissue, wall of methylene blue stained with electric knife or scissors in the direction of the probe. All scar tissue around the mouth and fistula, making the wound completely open. After stopping bleeding, the wound is filled with Vaseline gauze.