Anal canal injury

　　The pathological changes of anal canal injury vary with the degree of injury, the nature of the injury, the method of action, the location, range, time, and whether there are injuries to other organs.

　　1Stab wound in the anal area

　　As hard foreign bodies such as metal, wood shavings, bamboo tips, etc., when a person falls from a height and lands on the buttocks, they can stab the anal canal and soft tissue of the buttocks, mostly due to accidental injury. However, during the war against the United States in Vietnam, the Vietnamese people set up bamboo tip stakes, often causing American soldiers to fall into traps and be injured; in rural areas, injuries from horn butting are common, when a fierce water buffalo becomes angry and chases after a person running away, the buffalo uses its horn to butt the buttocks, commonly resulting in stab wounds to the anal canal and soft tissue of the buttocks, and tears in the anal canal.

　　2, weapon injuries

　　During wartime, shrapnel and bullets hitting the anal area accounted for a very low proportion in the ratio of battle injuries, and our army's counter-attack on Vietnam (1979In parentheses, rectal and anal injuries account for only3.64％.

　　3, contusion and laceration

　　Commonly seen in people with mental abnormalities or sexual deviations, causing injury by inserting foreign objects into the rectum and anal canal; it can also occur in iatrogenic cases, such as during rectoscopy or sigmoidoscopy, when the patient fears to contract the anal sphincter and the examiner uses rough force; in addition, forgetting to remove the thermometer during rectal temperature measurement, causing the thermometer to break and cut the anal canal, such injuries are usually mild; in anal surgery, such as incorrect anal fistula surgery, leading to anal incontinence, is more serious.

　　Early in anal canal injury, due to fecal contamination, pelvic cellulitis often occurs, and in the long term, it can cause anal stenosis and anal incontinence.

　　1, pelvic adnexitis

　　Pelvic adnexitis is a pelvic inflammatory disease, which can be divided into acute and chronic, acute pelvic adnexitis. Pelvic adnexa are extraperitoneal tissues located behind the pelvic peritoneum, on both sides of the uterus, and in the prevesical space. There are no obvious boundaries between the adnexal tissues at these sites. Acute pelvic adnexitis refers to the initial inflammation of pelvic adnexa, not secondary to fallopian tube or ovary inflammation, but initially originating from the adnexa around the uterus, then spreading to other sites. Chronic pelvic adnexitis. Chronic pelvic adnexitis is often due to incomplete treatment of acute pelvic adnexitis or poor physical condition of the patient, resulting in prolonged inflammation.

　　2, anal stenosis

　　Anal stenosis refers to the narrowing of the anal canal due to various reasons, which leads to difficulty in defecation, thin stools, anal pain during or after defecation, and a series of clinical symptoms. According to the onset time, it can be divided into congenital anal stenosis and acquired anal stenosis.

　　3, anal incontinence

　　Anal incontinence is a symptom of defecation dysfunction, where patients lose control over expelling and defecating.

　　After anal canal injury, anal pain, bleeding, or anal incontinence may occur, leading to difficulty in defecation and thin stools. Early examination after injury may show lacerations and bleeding around the anal area and surrounding tissues. In cases of transverse section of the anal sphincter, there is often fecal leakage and contamination. In cases with a longer duration, there may be severe local infection, with deep cellulitis of the gluteus maximus. Those with a history of anal trauma and symptoms such as anal pain, bleeding, anal incontinence, and difficulty in defecation should suspect anal canal injury. The diagnosis can be confirmed by finding bloodstains on gloves, decreased or relaxed anal sphincter tone, anal wall damage, pain, and a sense of emptiness.

　　There is no effective preventive measure for anal canal injury, early detection and early diagnosis are the key to the prevention and treatment of the disease. In daily life, attention should be paid to avoid anal canal trauma, and operation should be carried out carefully during anal surgery.

　　Anorectal injury patients should undergo a complete blood count, which shows an increase in white blood cell count and neutrophils. An anal examination must be performed under strict aseptic conditions using gloves. The finger should be gentle when entering the anal and rectal examination, and the patient is instructed to contract the anal sphincter to understand whether there is a rupture of the anal sphincter muscle. If there is a rupture, the anal opening will lose tension and become relaxed. If only partially torn, the tension of the sphincter can still be felt. Through the examination, it can also be understood whether there is a perforation of the low rectum, which can be judged from the examiner's feeling. If the intestinal wall is smooth, there is no injury. If there is a perforation, there will be local pain and a feeling of emptiness.

　　Diet has little significance for the relief of symptoms in patients with anorectal injuries, and it is recommended to eat more vegetables and fruits, and often drink Huaiju drink to prevent constipation. The other dietary requirements should be based on the specific symptoms of the patient, and specific medical advice should be sought to formulate different dietary standards for the disease.

　　Anorectal injuries are mostly caused by trauma or surgical injury, and treatment should pay attention to the distinction between early and late stages.

　　1、early treatment

　　(1) Debridement and drainage: When debriding locally for anal injuries, it is important to preserve tissue as much as possible. After alignment, suture repair should be performed to prevent malunion; except for one rupture, the anal sphincter muscles should be sutured and not excised. After local debridement, a transverse double-layer suture should be performed, and a smoke drain should be placed in front of the sacrum around the anal canal.

　　(2) Proximal stoma: To prevent local infection after the repair of the anal and anorectal areas, a sigmoid colon stoma should be made at the proximal end. This allows the repair site to rest sufficiently and heal smoothly. The distal sigmoid colon and rectum should be thoroughly irrigated with saline, and cleaned with neomycin and metronidazole solutions.

　　(3) Prevention and treatment of infection: Third-generation cephalosporins such as cefoperazone (先锋必) or ceftriaxone (菌必治) and metronidazole, etc., should be used before, during, and after surgery to prevent and treat infection.

　　2、late treatment

　　Due to the scar deformity of the anal canal in the late stage of anorectal injury, the anal canal will become narrow and incontinent, which seriously affects the quality of life of the patient. Therefore, in the later stage, treatment is mainly aimed at anorectal stricture and incontinence.

　　(1) Treatment of anorectal stricture: The incidence of severe scar deformity or extensive stricture after anorectal injury can be as high as32.8％. The treatment of fibrous stricture usually needs to be done after the trauma has healed.3～6months, after the inflammation of the perianal tissue subsides.

　　① Anorectal dilation: For mild anorectal stricture, mainly use hard rubber tubes or metal dilators to repeatedly dilate the stricture part, gradually increasing the diameter of the dilator until it can pass the surgeon's little finger. The dilation should be gentle to avoid causing further tearing and exacerbating the scarring stricture. The initial dilation should be performed1次/d，待正常排便后，改为每周1～3次，连续扩张半年。

　　② Anorectal strictureplasty: For severe stricture with poor dilation effect, anorectal strictureplasty can be performed. The patient assumes a lithotomy position, and a longitudinal incision is made from the anal opening to the coccyx. The stricture scar tissue behind the anal conjunctive is incised, starting from the dentate line to the anal opening.5cm. Full exposure of the incision, inspect the external sphincter, especially the subcutaneous part. If fibrosis is present, the sphincter in this area should be incised, and several mosquito forceps should be used to grasp the edge of the normal rectal mucosa.2cm，再用小弯剪刀游离1cm，仔细牵拉已游离的直肠黏膜，将其边缘间断缝合于肛门口皮下组织上(不包括肌肉组织)。严重肛门狭窄者，可在切除瘢痕后将直肠拉下，可使部分伤员直肠恢复功能。

　　(2)肛门失禁的治疗：外伤性肛门失禁在战时多为括约肌断裂伤，而在平常由于括约肌过度扩张致肛门闭合无力，括约肌本身并无断裂，称为括约肌松弛。

　　①括约肌断裂修补法：触诊确定括约肌断端之所在，在瘢痕组织的每一边作放射形切口，游离出断裂的肌肉断端，加深切口，切除瘢痕组织。游离部分直肠壁，肌肉断端上保留少量纤维组织，以便缝合时有一坚固的基部。将括约肌的断端作一“8”字形缝合，修剪皮肤边缘后，作松散的缝合或保留开放。对于严重的失禁者，可用一侧或两侧股薄肌，代替肛门括约肌的括约功能。

　　②括约肌松弛修整法：在肛门前面3.7～4.0cm处作一半环形切口，其凹面恰对肛门后方。分离皮瓣显露外括约肌皮下部的前面部分，将显露之外括约肌皮下部两个外缘间断对合缝合，使肛门适可容纳一指为度。间断缝合皮瓣，皮下置橡皮片引流，轻度加压包扎。

　　③括约肌刺激法：近年来，对于肛门、直肠创伤或感染所致的肛门失禁，使用盆底和会阴部肌肉的连续电刺激治疗取得一定效果。在盆底肌肉保持完整，而无感染和肛门周围严重瘢痕，括约肌、提肛肌无严重纤维化者，可使用电刺激治疗。此法有2种装置：A.埋藏式装置：两个电极通过会阴部切口，放置在盆底肌肉部位，导线通过皮下连接到腹直肌筋膜下的电子装置上。缺点是有异物反应，损伤组织，可能发生感染。B.肛塞式装置：将两圈哑铃式不锈钢环电极置入肛门内，通过导线连接到刺激器上。此法使用方便，通过电刺激随意肌的锻炼，使无力的肌肉恢复功能。