Anal fissure is a small longitudinal ulcer formed by laceration of the anal canal or anal margin, which can extend from the junction of the skin and mucous membranes to the dentate line. It is mainly characterized by periodic pain caused by defecation, a small amount of fresh bleeding during defecation, with or without constipation. Anal fissure can occur at any age, but it is more common in young adults, and there is no significant difference in incidence between men and women. More than 90% of anal fissures are located in the posterior midline of the anal canal. Preanal fissures are more common in women, but not more than 10%, while only 1% of male anal fissures belong to clj. When an anal fissure occurs in an abnormal part, especially when there are multiple splits on the side, consideration should be given to the presence of intestinal inflammatory diseases, especially Crohn's disease. Clinically, anal fissures are often divided into acute anal fissures and chronic anal fissures. Acute anal fissure has a short onset time, with a light red background, fresh and neat cracks, no scar formation, and most can heal by itself. Chronic anal fissures have recurring attacks, a long course of disease, and deep irregularities in the bottom of the fissure, often forming a typical triad of anal fissures: well-defined and limited anal ulcers, hypertrophy of anal papillae and sentinel hemorrhoids, due to long-term inflammation stimulation and fibrous tissue , Chronic anal fissures often cause anal stenosis, most of which require surgical treatment.
1 The etiology and pathogenesis of anal fissure
In general, the etiology and pathogenesis of anal fissure are still unclear. Current research shows that the following factors are closely related to the occurrence of anal fissure.
1.1 Trauma The usual theory is that the repeated damage of the hard stool to the anal canal during chronic constipation leads to the formation of chronic ulcers. However, studies have shown that only 25% of patients with anal fissure have a history of constipation, and a considerable number of patients have stool frequency. Increased or diarrhea. The high resting pressure of the anal canal, which may be caused by constipation or diarrhea, is a high risk factor for anal fissure.
1.2 Local anatomy Many studies have shown that the back of the anal canal mucosa has the weakest support and poor flexibility1; the blood volume of the back anal mucosa is less than that of other parts of the anal canal, and the blood volume of the anal mucosa at the anal fissure is also lower than that of the normal population ∞ J. This suggests that anal fissure may be caused by ischemia.
1.3 Infection Chronic inflammation near the tooth line spreads downward to form an abscess, which ruptures into a chronic ulcer.
2 Surgical treatment of anal fissure Surgical treatment should be adopted when anal fissure is ineffective or recurrent after conservative treatment.
2.1 Anesthesia for anal fissure surgery
Most anal fissure operations can be performed with local infiltration anesthesia in outpatient clinics. When anal fissures are combined with fissures, abscesses, and hemorrhoids, we often use sacral block or epidural block, which can achieve satisfactory anesthesia effects. Under normal circumstances, there is no need to use general anesthesia, because appropriate preoperative and intraoperative medications can have sufficient sedative, anti-anxiety and amnestic effects. Usually 0.5-1 hour before surgery, intramuscular injection of diazepam (Valium) 10mg or tiapride 0.1mg, in order to prevent anxiety and relieve pain after surgery. During the operation, proper amount of propofol or fentanyl combined with midazolam (midazolam) intravenous injection under strict respiratory and circulation monitoring can obtain satisfactory sedation and amnesia. Postoperative local injection of long-acting lidocaine or the addition of non-steroidal anti-inflammatory drugs to the anus can significantly reduce pain.
2.2 Surgical treatment
2.2.1 Anal canal dilation Recamier was the first to apply this method to treat anal fissures in 1838. After anesthesia, insert the index finger of one hand into the anal canal first, then insert the index finger of the opposite hand, gently pull the two index fingers on both sides for 30 seconds, then insert the middle fingers of both hands one after another, and carefully expand the anal canal with 4 fingers 4-5 minutes. Some hospitals also use anal canal retractors or balloons to expand the anal canal. This method is quick, effective and simple to relieve the symptoms of anal fissure, but it is easy to relapse, and the internal and external sphincter expand at the same time. For nearly 10 years, this method has been replaced by internal sphincterotomy.
2.2.2 Internal sphincterotomy The internal sphincter is a continuation of the distal part of the circular muscle of the rectum. It is an involuntary muscle that is prone to spasm and contraction. The complete cut of the internal sphincter does not produce obvious defecation control damage, so it can pass internally. Sphincter incision to relieve spasm, reduce the pressure of the internal sphincter, reduce the resting pressure of the anal canal, restore the normal extensibility of the anal canal, and improve the local blood supply to heal the anal fissure. There are two main methods for internal sphincterotomy.
184.108.40.206 Posterior internal sphincterotomy This method directly cuts the lower edge of the internal sphincter through the anal fissure, from the anal edge to the dentate line, and sometimes also cuts the lower part of the external sphincter to facilitate drainage and open the wound. Heals on its own. If combined with external hemorrhoids and enlarged nipples, they can be removed at the same time. The curative effect of this method is definite. Domestic Han Jinlin-4o has reported that all 60 cases were cured without recurrence. However, this method slows wound healing and tends to form groove-like scars, leading to "keyhole"-like deformities. About 5% to 10% of defecation disorders occur. Therefore, people with loose anus should be handled with caution.
220.127.116.11 Lateral internal sphincterotomy is divided into closed and open techniques, generally selected at 3 or 9 o'clock on the side. Closed: You can insert an ophthalmic cataract scalpel or other small sharp knife from the quadratus sulcus on the side of the anal canal, and incise the internal sphincter from the outside to the inside. The knife can also be inserted from the submucosa and cut laterally to the intermuscular groove. After pulling out the blade, press with your fingers to break the remaining sphincter fibers. The wound does not require special treatment. The advantage of this surgery is that it is less painful and quick to recover, but it may be incomplete muscle amputation, which is suitable for experienced doctors to operate. Open: After touching the intersphincteric groove with your fingers, make an arc-shaped incision about 1.5cm in length on the side of the anus about 1cm. The white internal sphincter fibers are cut under direct vision, the wound is open, and silk sutures can also be used. The advantage of this procedure is that it can be performed under direct vision, hemostasis is thorough, and tissues are taken for biopsy.
18.104.22.168 Anal fissure resection is suitable for the anal canal skin with large defects and anal fissure combined with anal stenosis. A fusiform incision is made at the anterior and posterior median anal fissure. If the combined sentinel hemorrhoids and anal papilla hypertrophy are combined, they can be resected at the same time. The longitudinal incision can be sutured horizontally with silk thread. Liao Xingzhong et al."1 improved it. The longitudinal incision was sutured appropriately and the length of the transverse slit incision remained unchanged, but the center was not sutured. A radial incision was reserved at the lower part for drainage, which seemed to reduce the tension of the transverse slit incision and speed up healing. Surgical suture cutting tissues sometimes affect wound healing. In addition, routine lateral internal sphincterotomy can reduce long-term recurrence.
22.214.171.124 Thread-hanging technique is suitable for anal fissure accompanied by fistula. Use a round needle and a 10-gauge double-stranded silk thread to insert the needle from the outer edge of the anal fissure, and exit the needle from the inner sphincter to the inner edge of the anal fissure to tighten the silk thread. This operation is performed synchronously with incision and drainage without dressing change. Intraoperative bleeding is less and the wound area is small. However, postoperative patients often need to use analgesics.
126.96.36.199 Flapplasty is mainly used for chronic anal fissures with typical triad of anal fissures or anal ulcers with high scarring hyperplasia and anal stenosis. First, cut open the narrow part of the anal canal, completely remove the bottom of the anal fissure ulcer, cut off the whiteish internal sphincter, pay attention to avoid damaging the red external sphincter, and remove sentinel hemorrhoids, hypertrophic nipple and skin tags. Make a V-shaped incision parallel to the lower edge of the wound at 1 to 2 cm from the lower edge of the wound. Cut only the epidermis and dermis, avoiding the subcutaneous fat, and suture the entire thickness of the flap to the rectal mucosa. This operation is due to the one-stage covering of the anal fissure, and the wound is cured quickly after surgery. The complications are less painful and lighter, but occasionally anal incontinence occurs. Note that this operation did not relieve the problem of sphincter spasm.
Current studies have confirmed that severe local ischemia in the anal canal caused by spasm of the sphincter at the base of the anal fissure is the main cause of anal fissure. The various methods of surgical treatment are basically to relieve internal sphincter spasm. The current surgical treatment methods are complicated and diverse. It seems that the clinical treatment effects reported by various units are also relatively satisfactory, but the actual situation may not be so optimistic. Clinically, anal fissure can be combined with anal sinusitis, anal papillary hypertrophy, internal and external hemorrhoids, fistula, diarrhea, and constipation. Individualized treatment should be implemented according to the specific conditions of the patient. In addition, there is no unified understanding and standard for various surgical methods, including the surgical approach and the degree of sphincter amputation, as well as how to reduce complications such as anal incontinence and changes in anal morphology, which need to be further studied by colleagues in clinical work.
 Goligher jc. Surgery of the anus, rectum and colon[M]. 4t}1. ed. New York: Macmillan, 1980.136.  Lockhart-Mummery P. Diseases of the rectum and anus[M]. New
York: William Wood, 1914.171.
 Schouten WR, Briel Jw, Anewerda JJA, et a1. Ischaemic nature of and fissure[J]. Br J Surg, 1996, 83:63.
 Han Jinlin, Li Feng, Han Bo, etc. Treatment of 60 cases of old anal fissure by cutting the internal sphincter muscle under the puborectal ring [J]. Chinese Journal of Anorectal Diseases, 2003,23(9):37.
 Liao Xingzhong, Wang Xiaolin. Modified longitudinal section and transverse suture operation for the treatment of old anal fissures [J]. Chinese Journal of Anorectal Diseases. 2001, 21(9): 9.