Small intestinal injury

　　Small intestinal injury is caused by direct and indirect violence, mainly seen in abdominal blunt trauma, intestinal rupture caused by falling from a height or sudden deceleration, and is generally believed that the rupture is prone to occur within 50cm from the Treitz ligament in the proximal jejunum and within 50cm from the ileocecal junction in the distal ileum. Traumatic damage can generally be divided into closed intestinal injury, open intestinal injury, and iatrogenic intestinal injury.

　　Closed intestinal injury

　　According to the different principles of violence, it can be divided into four situations.

　　(1) Injury caused by direct violence: The lumbar sacral physiological curve is closer to the abdominal wall than other vertebrae. Direct violence acts on the abdominal wall and is transmitted to the lumbar sacral direction, causing injury to the small intestine or including the mesentery.

　　(2) Injury caused by lateral violence: External force can also act on the abdomen along the oblique direction of the body axis, causing the intestinal tract and mesentery to move rapidly to one side. When the range of movement exceeds the bearing capacity of the fixed intestinal tract mesentery or ligaments, it may cause the intestinal tract to tear from the attachment point. The most common sites are near the beginning of the jejunum close to the Treitz ligament or the terminal end of the ileum fixed by the peritoneum. By the same logic, such injuries can also occur in abdominal inflammatory lesions, abdominal surgery, or after abdominal intravenous medication, which may cause pathologic adhesions in the abdominal cavity, and near the fixed points of the intestinal tract with the abdominal wall or surrounding organs.

　　(3) Injury caused by indirect violence: This often occurs under the mechanism of resistance against the inertia movement of the intestinal tract. When a patient falls from a height, sustains a fall injury, or experiences an abrupt stop, the intestinal tract or mesentery cannot withstand the pressure caused by the sudden change in position, leading to the breakage or tearing of the small intestine. This kind of injury often occurs at the fixed ends of the small intestine, such as near the ends of the jejunum and ileum attached to the posterior abdominal wall and the most mobile junction of the jejunum and ileum.

　　(4) Injury caused by strong contraction of the abdominal muscles: Improper exertion can cause the body to suddenly arch backward, causing the abdominal muscles to contract strongly, increasing intraperitoneal pressure and leading to tears in the small intestine or mesentery. In some cases, the contraction of the abdominal muscles may counteract the normal movement of the intestinal tract.

　　Open intestinal injury

　　It is mainly caused by sharp objects such as bullet wounds, shrapnel, or BB injuries. Open small intestinal injuries must have foreign bodies entering or passing through the abdominal cavity, which may be a single wound injury or multiple wound injuries. The injured intestinal tract can be far from the wound site, often causing multiple intestinal perforations or complex injuries.

　　Iatrogenic intestinal injury

　　Small intestinal injury in medical practice also occurs occasionally. Common causes include unintentional injury to the intestinal tract during surgical separation of adhesions, injury to the distended or highly distended intestinal tract during abdominal puncture, accidental injury during endoscopic procedures, and injury to the small intestine during induced abortion surgery, leading to intestinal perforation or rupture. Sometimes, the injury may also cause hematoma by forming blood clots in the vessels of the jejunum and ileum.

　　The small intestine occupies the largest position in the abdominal cavity, has a wide distribution, is relatively superficial, and lacks skeletal protection, making it prone to injury. In open injuries, the injury rate of the small intestine is 25% to 30%, and in closed injuries, it is 15% to 20%. When any abdominal injury requires exploration, the examination of small intestinal injury should be carried out seriously, meticulously, and regularly. Small intestinal injury can be accompanied by rupture of abdominal visceral organs, causing hemorrhage and shock, as well as multiple organ and tissue injuries. Improper or timely treatment can easily lead to the occurrence of complications. Common complications include:

　　1, Peritonitis

　　Peritonitis is a common severe surgical disease caused by bacterial infection, chemical stimulation, or injury. Most cases are secondary peritonitis, originating from organ infection in the abdominal cavity, such as necrosis and perforation, trauma, and others. The main clinical manifestations are abdominal pain, abdominal muscle tension, nausea, vomiting, fever, and in severe cases, blood pressure can drop and systemic toxic reactions can occur, leading to toxic shock if not treated in time. Some patients may develop complications such as pelvic abscess, interintestinal abscess, subdiaphragmatic abscess, iliac fossa abscess, and adhesive intestinal obstruction.

　　2, Shock

　　Shock (shock) is a clinical syndrome characterized by acute effective blood volume deficiency caused by various severe pathogenic factors, leading to neuro-humoral factor imbalance and acute circulatory disorder. These pathogenic factors include massive hemorrhage, trauma, poisoning, burns, asphyxia, infection, allergy, heart pump function failure, and others.

　　3, Poisoning

　　Exposure to excessive or large amounts of chemical toxins, causing tissue and functional damage, metabolic disorders, and resulting in disease or death is called poisoning. The severity of poisoning is related to the dose and often shows a dose-effect relationship; poisoning can be divided into acute poisoning, subacute poisoning, and chronic poisoning according to its occurrence and development process. Poisoning caused by a single exposure to a large amount of toxins is acute poisoning; poisoning caused by repeated or long-term exposure to small amounts of toxins after a certain incubation period is chronic poisoning; those between the two are subacute poisoning. Sometimes it is also difficult to distinguish.

　　The clinical manifestations of small intestinal injury depend on the degree of injury, the time of injury, and whether there is injury to other organs.

　　Contusion of the intestinal wall or hematoma may cause mild or localized peritoneal irritation symptoms in the early stage of injury. The patient's overall condition is not significantly changed. With the absorption of hematoma or the repair of contusion inflammation, abdominal signs may disappear, but they can also cause intestinal wall necrosis and perforation, leading to peritoneal inflammation due to pathological changes.

　　When the intestine ruptures or perforates, the contents of the intestine overflow, and the peritoneum is stimulated by digestive juices, causing the patient to experience severe abdominal pain, accompanied by nausea and vomiting. Physical examination may reveal pale complexion, cold skin, weak pulse, rapid breathing, and decreased blood pressure. There may be generalized abdominal tenderness, rebound pain, abdominal muscle tension, positive shifting dullness, and disappearance of bowel sounds. With the passage of time since the injury, the symptoms of infection and poisoning become more severe.

　　After the rupture of the small intestine, only a portion of patients have pneumoperitoneum. If there is no manifestation of pneumoperitoneum, the diagnosis of small intestinal perforation cannot be negated. Some patients may not show clear peritoneal inflammatory symptoms for several hours or a dozen hours after small intestinal injury due to small orifice laceration, food residue, fibrinogen, or protruding mucosa, which is called the asymptomatic period. It is necessary to observe the changes in abdominal signs.

　　Small intestinal injury can be accompanied by rupture of abdominal solid organs, causing hemorrhage and shock, and can also be accompanied by multiple organ and tissue injuries. It should be emphasized to understand the injury situation seriously and make an accurate diagnosis.

　　The mortality of small intestinal injury depends on whether the operation is timely and whether there are associated organ injuries. According to literature reports, the mortality rate is 7.3% within 12 hours after injury, and it reaches 27.3% after 12 hours. The mortality rate of simple small intestinal injury is below 5%, and it rises sharply with the increase of associated organ injuries. Then, how should we prevent it in daily life?

　　There are no specific preventive measures for small intestinal injury, mainly to avoid trauma.

　　10. Pay attention to diet; eat less spicy, greasy, and other strongly stimulating foods. Eat more light foods containing a lot of fiber, such as fresh fruits and vegetables, which can help the normal peristalsis of the intestines and smooth defecation.

　　9. Engage in moderate exercise; do not sit or stand for long periods of time. Be active in physical exercise to promote blood circulation in the body and enhance the body's resistance.

　　8. Pay attention to personal hygiene; do not live in a too damp and dark environment. It is best to clean the anal area with warm water every day to keep the perianal area clean and hygienic. Personal hygiene products should not be mixed, to avoid infection.

　　Small intestinal injury is caused by direct and indirect violence, mainly seen in abdominal blunt trauma, intestinal rupture caused by falling from a height or sudden deceleration, etc. In diagnosis, digestive fluid or bloody fluid can be obtained through diagnostic peritoneal puncture, and diagnosis is generally not difficult, but some auxiliary examinations are still needed to confirm the diagnosis for the benefit of treatment.

　　1. X-ray examination

　　Standing or lateral recumbent position for abdominal X-ray透视 or filming; the presence of free gas under the diaphragm or free gas in the lateral abdomen is the most powerful evidence for the diagnosis of closed abdominal injury with perforation of the small intestine, but the positive rate is only 30%. When performing X-ray examination, it is necessary to exclude factors such as pneumoperitoneum caused by abdominal open wounds and iatrogenic pneumoperitoneum.

　　2. Peritoneal puncture

　　For suspected intestinal rupture, diagnostic peritoneal puncture can be performed first. Peritoneal puncture is one of the commonly used auxiliary diagnostic or confirmatory methods for abdominal trauma and acute abdominal conditions, with a diagnostic rate for intestinal rupture reaching 70% to 90%. As long as the puncture site does not damage the gallbladder, bladder, or adhesions on the abdominal wall, it can be performed in any part of the abdomen in principle. Generally, it is often on one or both sides of the lower abdomen, or on both sides of the upper abdomen or at the level of the umbilicus, depending on the mechanism of injury. When puncturing, a needle with sufficient length and caliber should be chosen; a too thin needle affects the outflow of abdominal contents, while a too thick needle undoubtedly increases the chance of abdominal injury. The needle angle should be blunt, and the needle tube should be able to provide a certain degree of negative pressure. If turbid, purulent fluid and intestinal contents are aspirated, the possibility of intestinal rupture should be considered, and further microscopic examination should be performed to confirm the diagnosis.

　　3. Abdominal lavage

　　To improve the early diagnostic rate of intestinal perforation and internal hemorrhage, after abdominal puncture and tube placement, 250 to 500ml of normal saline is injected through the catheter. After appropriate changes in position and a brief pause, part of the fluid infused into the abdomen is aspirated. By observing the color, clarity, smell, and laboratory examination, the condition inside the abdomen can be analyzed and judged.

　　4. Ultrasound examination

　　Ultrasound does not harm the body, has simple equipment, and is inexpensive. It can be performed repeatedly at the bedside and can also guide specific puncture sites for interventional diagnosis, which plays an important role in the diagnosis of abdominal injury. There are reports that the minimum amount of abdominal fluid detectable by B-ultrasound is about 200ml, which can be expressed as local hypoechoic fluid areas in the recesses, depressions, or gaps of the abdomen. There is shadowing behind the sound. When there is gas in the abdomen, it can be used to find gas on the opposite side of gravity, which is shaped like a sky curtain, closely attached to the abdominal wall, and moves with the position of the body.

　　5. CT examination

　　CT is a diagnostic method that uses the body's absorption of X-rays, processed by a computer to produce imaging. The detection rate of free abdominal air in the early stage by CT can reach 48% to 70%. With higher resolution than ultrasound, accurate localization, repeatable, and helpful for excluding the diagnosis of solid organ injury and internal hemorrhage. CT examination can clearly determine the location and size of the hematoma.

　　6. Selective arterial angiography

　　Selective arterial angiography can diagnose diseases by imaging through arteries, veins, and capillaries. It is most suitable for the diagnosis of vascular injury, especially active bleeding, and the application of vascular angiography has a certain effect on small intestine injury with rupture of mesenteric vessels.

　　Patients with small intestine injury should have a regular and moderate diet, not allowing themselves to be overfull or underfed. Pay attention to the quality of food, as a reasonable and effective diet often makes the treatment of diseases twice as effective. So, in daily life, what kind of food is beneficial to patients with small intestine injury?

　　1. To protect the small intestine, one can eat noodles, noodles with pieces, wontons, tender green leaves, fish, shrimp, eggs, and soybean products to allow the intestines to rest.

　　2. Eat less spicy and stimulating foods as well as those that are not easy to digest or too sticky, such as zongzi and nian gao, to prevent them from sticking to the intestinal wall.

　　3. The diet should be as light as possible, and food should be chewed and bitten thoroughly. It is because the small intestine is fragile and cannot be eaten in large mouthfuls, so it is best to use the mouth to replace some of the digestive functions of the stomach.

　　4. After surgery, try to eat less and more meals, and do not eat too much at each meal. The transition from liquid to semi-liquid to normal food may take a long time, but it is important to take good care of the patient.

　　The prognosis of traumatic intestinal rupture is closely related to the timeliness and rationality of treatment. For intestinal rupture in multiple injuries, treatment should be prioritized based on the severity and urgency, and comprehensive measures should be taken. For those with surgical indications, except for a few critically ill patients who cannot tolerate surgery or even the simplest and most effective surgery cannot be tolerated, early surgical treatment should be performed, because these patients cannot relieve shock without surgery, and it is impossible to wait for the condition to stabilize before surgery. It is worth mentioning that for patients with sufficient preparation and active surgery, even for critically ill cases with very small hopes, the success rate of rescue is very high.

　　1. Non-surgical treatment

　　(1) Fluid replacement and nutrition

　　Establish a venous access rapidly, replenish water and electrolytes, maintain a smooth infusion, and pay attention to correct imbalances in water, electrolytes, and acid-base balance. For patients with shock and severe diffuse peritonitis, central venous catheterization for fluid administration can be performed, and the fluid volume to be replenished is determined based on the central venous pressure. According to the specific condition of the patient, appropriate amounts of whole blood, plasma, or human serum albumin should be administered, and sufficient calories should be provided as much as possible. For critically ill patients after surgery, those with poor physical condition, and those who may develop an intestinal fistula after intestinal resection and anastomosis, total parenteral nutrition can be provided to reduce the patient's own consumption and enhance their ability to resist disease.

　　(2) Abstain from food and gastrointestinal decompression

　　It can reduce the secretion of digestive juices, aspirate the gases and fluids in the gastrointestinal tract, thereby reducing the continuous overflow or infection spread of intestinal contents, reducing the entry of bacteria and toxins into the blood circulation, and is conducive to the improvement of the condition.

　　(3) The use of antibiotics

　　The use of antibiotics has a certain effect on preventing and treating bacterial infections, thereby reducing the production of toxins. Early use of broad-spectrum antibiotics can be selected, and adjustments can be made later based on the results of bacterial culture and drug sensitivity tests. For severe intra-abdominal infections, third-generation cephalosporins such as ceftriaxone (Forte) and ceftriaxone (Roth芬) can be selected.

　　(4) Treatment of septic shock

　　Intestinal rupture complicated with septic shock requires timely and effective rescue. The measures include: ①Rapidly replenish an adequate blood volume: mainly with balanced salt solution, supplemented with appropriate plasma and whole blood. If the blood volume can be replenished in time in the early stage, shock can often be improved and controlled. ②Correct acidosis: In septic shock, acidosis occurs early and is severe. Acidosis can worsen microcirculatory dysfunction, which is not conducive to the recovery of blood volume. While replenishing blood volume, 200ml of 5% sodium bicarbonate is infused through another vein, and further supplementation is made based on the CO2 binding capacity or the results of arterial blood gas analysis. ③The use of corticosteroids: Dexamethasone is commonly used, 20-40mg per dose, once every 4 hours. ④The use of cardiovascular drugs: In the case of sepsis, the heart function is damaged to a certain extent, and drugs such as digoxin (Lanoxin) can be used for treatment. Commonly used drugs include dopamine, metaraminol (Aramine), and others. ⑤The use of high-dose combination of broad-spectrum antibiotics.

　　2、Operation exploration

　　The treatment of small intestinal injury is often carried out simultaneously with the treatment of abdominal injury. While dealing with small intestinal injury, it is also necessary to comprehensively consider the treatment of other parts of the injury without neglecting one aspect while focusing on another, so as not to cause delay in treatment.

　　(1) Exploration criteria

　　① There are signs of peritonitis, or they are not obvious at the beginning but become more severe with the progression of time, with the intestinal sounds gradually weakening or disappearing;

　　② Abdominal puncture or abdominal lavage fluid examination is positive;

　　③ X-ray abdominal flat film showing pneumoperitoneum;

　　④ The patient arrives late, has a typical injury history, presents abdominal distension and shock, and should actively prepare to create conditions for operation exploration.

　　(2) Operation exploration

　　After anesthesia is stable, further cleaning treatment should be performed for the contaminated wounds caused by open abdominal injuries and the protruding viscera to prevent more pollution of the abdominal cavity.

　　The laparotomy exploration is usually taken with a right lateral midline incision or a right transverse rectus sheath incision, with the midpoint of the incision at the level of the umbilicus. If necessary, it can be extended upwards or downwards.

　　If there is a large amount of blood in the abdominal cavity after entering the abdomen, the following order should be checked: liver, spleen, both diaphragmatic muscles, stomach, duodenum, duodenojejunal flexure, pancreas, omentum, intestines and their mesentery, and finally check the pelvic organs. A large amount of blood clots often suggests that the bleeding site is where there are more blood clots. Only after the bleeding has been controlled can the focus be placed on finding and treating intestinal injuries, and the exploration should not ignore or miss perforations inside the mesentery or hidden in the hematoma. When there are multiple injuries in the intestinal tract, the rupture sites are generally in pairs. If only a single wound is seen during the exploration, it should be tried to find another hidden wound.

　　Mesenteric tearing may cause very severe bleeding. After controlling the mesenteric bleeding, the color changes of the loops and blood supply should be carefully observed. If the intestinal wall is purple and cannot recover after hot saline wrapping, it reflects that the intestinal blood circulation disorder is irreversible and must be resected according to the necrotic intestinal loops. When the mesenteric rupture injury is perpendicular to the intestinal tract, the opportunity to cause circulatory disorders is less. Mesenteric rupture that is parallel to the intestinal tract and exceeds 3cm is prone to cause circulatory disorders and requires partial resection of the intestinal tract. For hematoma inside the mesentery that has progressive enlargement, it is necessary to make a longitudinal incision, remove blood clots, ligate bleeding points, and observe whether there is circulatory disorder in the intestinal tract. When there is significant vascular injury, it should be repaired and sutured, and it is necessary to prevent the extensive necrosis of the intestinal tract caused by the ligation of a large piece of mesenteric root vascular pedicle. After exploration, the mesenteric incision can be sutured in an interrupted manner.

　　After laparotomy, if there is no severe bleeding or bleeding has been effectively controlled, the small intestine and its mesentery should be sequentially examined starting from the Treitz ligament or ileocecal region. One by one, the loops of the intestine should be pulled out of the incision and carefully and meticulously examined under direct vision without missing any part. Pay attention to small ruptures and hidden small perforations. For the perforations that have been found, prevent the intestinal contents from continuing to flow into the abdominal cavity, and temporarily use Allis forceps and saline gauze to wrap it until the entire intestinal examination is completed, and then decide on the treatment method.

　　(3) Surgical principles and methods

　　① Intestinal repair: Suitable for fresh small perforations or linear fissures at the edge of the wound, which can be sutured with silk thread in an interrupted transverse manner. Before suturing, a thorough debridement should be performed, removing the necrotic tissue around the rupture, tidying up the intestinal wall with good blood supply, and preventing postoperative intestinal rupture or fistula.

　　② Intestinal resection: Intestinal resection surgery is suitable for:

　　A. Large defects at the rupture of the intestinal wall, irregular incisions, severe contamination, and longitudinal lacerations that may cause intestinal stricture after suture;

　　B. Multiple irregular perforations in a limited small segment of the intestinal tract;

　　C. Severe contusion or bleeding in the intestinal tract;

　　D. Large hematoma at the mesenteric margin of the intestinal tract;

　　E. Large hematoma inside the intestinal wall;

　　F. Large segmental avulsion between the intestinal wall and mesentery exceeding 3cm;

　　G. Severe contusion, transverse avulsion, or tearing of the mesentery causing intestinal wall blood flow disorders;

　　H. Severe compression injury to the intestinal tract, unable to confirm whether the intestinal tract reimplanted into the peritoneal cavity will not cause secondary intestinal necrosis;

　　I. Some believe that intestinal resection should be performed when the length of the tear is equal to or exceeds 50% of the diameter of the intestinal tract, or when the total length of multiple tears in a small segment of the intestinal tract is equal to or greater than 50% of the diameter of the intestinal tract.

　　In the process of intestinal resection and anastomosis, in order to prevent anastomotic fistula and intestinal rupture, attention should be paid to the blood circulation of the distal ends, prevent local blood supply disorders, carefully handle the bleeding points of the intestinal wall and mesentery, and prevent the formation of anastomotic and mesenteric hematoma.

　　③ Intestinal fistula: For patients with intestinal perforation of the jejunum and ileum exceeding 36-48h, intestinal segment contusion, or severe peritoneal contamination, especially when intestinal resection and anastomosis is not allowed during surgery, consideration can be given to external intestinal stoma. After the postoperative recovery of the body and the improvement of the peritoneal conditions, the stoma can be reimplanted. Intestinal fistula surgery will cause the loss of digestive tract contents, and it should be avoided to create a fistula at the site of jejunal rupture.

　　④ Peritoneal lavage: For patients with severe peritoneal contamination, in addition to thoroughly removing pollutants and fluids, the peritoneal cavity should be flushed repeatedly with 5-8°C saline solution.