External anal sphincter rupture

Introduction The external anal sphincter starts from the dorsal aspect of the tailbone and the anal talus ligament. It is divided forward and downward, and is divided into two parts at the back of the anus. It surrounds the sides of the anal canal to the front of the anus, and is combined with the second to stop at the perineum. The external sphincter is divided into three parts: the lower part of the skin, the shallow part and the deep part. The lower part of the skin is generally identifiable. There is no obvious dividing line between the shallow part and the deep part, which is difficult to distinguish, but the former is elliptical and the latter is round. The two are different in appearance. The external anal sphincter is innervated by the anal nerve. It has an important role in circumventing the anus and controlling bowel movements. If it is accidentally injured during surgery, it can cause incontinence. An external sphincter rupture can destroy the function of the external anal sphincter, leading to fecal incontinence.

Cause

(1) Causes of the disease

The main and common causes of fecal incontinence are:

1 nervous system disorders: cerebrovascular accident cerebral arteriosclerosis, brain trauma, spinal cord injury, spinal cord, spina bifida.

2 knot, rectal disease: congenital megacolon, ulcerative colitis, knot, rectal cancer rectal prolapse, anorectal malformation.

3 Anorectal direct injury, in which surgical injury is a common cause. Surgery including anal fistula, anal fissure, and hernia, as well as sclerotherapy injections.

In addition, there are perineal tears, accidental injuries, gunshot wounds and foreign bodies. The elderly are weak, and fecal impaction can also cause incontinence. The details are as follows:

1. Anal stab wound: such as metal, wood chips, bamboo tips and other hard foreign objects, when the body falls from the heights of the hips to the ground, stabbing the anus and buttocks soft tissue, mostly accidental damage. However, in Vietnams war against the United States, the Vietnamese people set bamboo pole piles, often causing the US troops to fall into a trap and causing injuries; in rural areas, common horns are wounded. When a fierce buffalo is angry, if a person flees, the murderous cow pursues from behind, using a horn Top of the buttocks, common anal, hip soft tissue stab wound, anal tear.

2. Firearm injuries: Wartime shrapnel and bullets hit the anus. In the proportion of war injuries, the incidence rate is very low. In the counterattack of the self-defense in our army (1979), rectal and anal injuries accounted for only 3.64%.

3. Contusion and laceration: more common in mental abnormalities or sexual metamorphosis, with foreign body stuffed into the anorectal injury; can also occur in iatrogenic, such as with a proctoscope, sigmoidoscopy, the patient is afraid of force to contract the anus, The examiner was violently forced. In addition, the body temperature of the anus was forgotten to be removed, and the body temperature was cut to cut the anus, and such damage was lighter. In the anal surgery, such as anal fistula surgery, and the occurrence of anal incontinence is more serious.

(two) pathogenesis

Pathological changes: pathological changes of anal canal injury vary with the degree of injury, the nature of the injury, and the method, location, extent, time, and presence or absence of other organ injuries. Light only mucosal tears and myometrial rupture, heavy full-thickness intestinal wall rupture and extensive sphincter damage or even transverse. If accompanied by large blood vessels and anterior venous plexus injury, it can cause major bleeding and shock. Anal canal injury is often accompanied by infection of surrounding tissues, such as deep cellulitis of the gluteus maximus, combined with anaerobic mixed infection and continuous contamination of intestinal feces, which can cause extensive necrosis, severe toxemia and sepsis, and even death.

an examination

Related inspection

Fecal odor anal inspection

1, the consultation:

(1) Medical history: to know whether there is surgery, birth injury, trauma history, course of disease and treatment.

(2) Symptoms:

1 self-control ability of defecation, whether it is convenient or not, self-care conditions for daily stool frequency.

2 anorectal symptoms, such as abnormal urination, spinal condition, intellectual intelligence and mental status.

2. Local inspection

Anal examination can be used to understand the presence or absence of local factors leading to fecal incontinence.

(1) Visual inspection: pay attention to the presence or absence of fecal contamination, ulcers, eczema skin scars, mucosal prolapse, anal expansion and so on.

(2) refers to the diagnosis: attention to the anal sphincter contraction force anorectal ring tension and so on.

(3) Endoscopy: Observe the color of the rectal mucosa, with or without ulcers, inflammation, bleeding tumors, stenosis and anal fistula.

3. Laboratory inspection

(1) Anorectal manometry: including the resting pressure controlled by the internal anal sphincter, the maximum pressure at the time of external contraction of the external sphincter, and the threshold of stimulation at the time of diastole. Anal resting pressure and maximum pressure are reduced during fecal incontinence.

(2) Electromyography: It is an objective basis for reflecting the physiological activities of the pelvic floor muscles and sphincters to understand the location and extent of nerve and muscle injuries.

(3) Defecation angiography: The dynamic changes during defecation can be recorded, and the state of the puborectal muscle and the degree of injury can be estimated by the change of the rectal angle.

(4) Saline enema test: 1500ml of normal saline was injected into the rectum by sitting, and the leakage and maximum retention were recorded to understand the self-control ability of defecation. When the stool is incontinent, the amount of retention decreases or is zero.

(5) Anal canal ultrasound: The thickness of the internal sphincter can be accurately determined by accurately determining the location and asymmetry of the anal sphincter defect.

Differential diagnosis

Identification of fecal incontinence:

It is mainly distinguished from the occasional loss of control of stool in patients with diarrhea such as acute bacillary dysentery and acute enteritis. However, in most cases, the stool of these patients can be controlled at will, and the patients often have abdominal pain and pus and bloody stools. After symptomatic treatment, stools are formed with the relief of diarrhea symptoms, and occasional fecal incontinence disappears. Fecal incontinence is mainly the identification of the cause, including neurological disorders and impaired muscle dysfunction and impaired congenital diseases.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.