Intestinal duplication anomaly

　　There are many theories of the etiology of intestinal duplication deformities, but each theory cannot fully solve the causes of repeated deformities at various sites. The etiology may be polygenic, and the etiology of different sites and different pathological changes may be different.

　　1. The theory of primitive gut cavitation disorder: After the 5th week of embryonic development, the rapid proliferation of epithelial cells in the primitive gut cavity causes temporary occlusion of the intestinal cavity. Later, the occluded intestinal cavity epithelial cells appear many vesicles, making the occluded intestinal cavity相通, that is, the cavitation period appears. If there is a developmental disorder at this time, the intestinal tract may appear parallel intervals with the digestive tract, which may form intestinal cystic type duplication deformities.

　　2. The theory of diverticulum-like external pouch: At 8-9 weeks of embryonic development, the distal small intestine forms a temporary diverticulum-like external pouch due to the outward proliferation of epithelial cells covered by connective tissue. This pouch gradually disappears later. If it remains, the diverticulum-like external pouch at the original site can develop into a cystic type of small intestinal duplication deformity.

　　3. The theory of the separation disorder of the notochord and primitive gut: At 3 weeks of embryonic development, the notochord is formed between the inner and outer germ layers. If there is abnormal adhesion between the inner and outer germ layers at this time, the notochord is divided into two parts, left and right, at this site. The notochord and vertebral body form a cord-like nerve gut between the outer germ layer and the digestive tract. When the inner germ layer develops into the intestinal tract later, the intestinal tract part pulled by the cord-like adhesion bulges to the dorsal side to form a diverticulum-like protuberance. This site can develop into a duplicated deformity later. Since the adhesions all occur on the dorsal side of the primitive gut, the duplicated deformities are also located on the mesenteric side. The cord-like adhesions can affect the development of the vertebral body, so this type of duplicated deformity often accompanies vertebral body developmental deformities, such as hemivertebrae, butterfly vertebrae, etc. Li Long et al. divided intestinal duplication deformities into two types, and the mesenteric type duplicated deformity is exactly located between the two mesenteries, accounting for 91.6%. It is proposed that this type is caused by the separation disorder of the notochord and primitive gut.

　　4. The theory of primitive gut ischemic necrosis: Many scholars believe that after the development of the primitive gut is completed, due to ischemic necrotic changes in the primitive gut, changes such as intestinal atresia, stenosis, and short small intestine occur. The remaining fragments of the intestinal tract receive blood supply from nearby vessels and can develop into duplicated deformities by themselves. Therefore, some children with small intestinal duplication deformities may simultaneously have intestinal atresia, stenosis, and short small intestine.

　　1. Respiratory symptoms: In addition to abdominal symptoms, respiratory or mediastinal compression symptoms may occur simultaneously due to repeated abdominal and thoracoabdominal deformities. Sometimes, the main symptoms are those of the thoracic cavity, with the child experiencing difficulty breathing, asthma, cyanosis, and mediastinal displacement. It is easily misdiagnosed as pneumonia or mediastinal tumor.

　　8. Intestinal torsion can cause acute, complete, and strangulated intestinal obstruction symptoms and signs due to the gravitational effect of the duplicated intestinal tract and the torsion of the elongated mesentery. It often occurs in newborns and infants. The onset is acute, the symptoms are severe, with severe vomiting and abdominal pain. The abdomen can often be palpated for the mass of torsion.

　　7. Intussusception is easily induced by intestinal duplication anomalies with intraluminal cysts located at the distal ileum and ileocecal region. Some authors report that 17 cases (26%) of intestinal duplication anomalies developed intussusception, including 15 cases under 1 year old, accounting for 88.2%, all with typical clinical manifestations of acute intussusception. Intussusception caused by duplication anomalies cannot be复位 by either air or water enema in most cases. Occasionally, after successful reduction by enema, there is still a mass in the abdomen, and cystic masses can still be seen under B-ultrasound.

　　6. Peritonitis is caused by the corrosive effect of ectopic gastric mucosa and pancreatic tissue on the intestinal wall, leading to intestinal perforation. Some reports indicate that all perforation sites have ectopic gastric mucosa, which has already formed ulcers, and the perforation is located at the bottom of the ulcer. Clinically, it presents with symptoms and signs of acute peritonitis, and in infants and young children, the signs may be不明显, and it is not easy to distinguish from acute appendicitis perforation. It requires patient and careful comparison of examinations.

　　The clinical symptoms of intestinal duplication anomalies vary greatly due to complex factors such as pathoanatomical characteristics, location, pathological morphology, size, whether they communicate with the intestines, and the presence of complications. Symptoms can appear at any age, with 60% to 83% occurring within 2 years, and many cases appear within one month of birth. A few cases are asymptomatic and are only discovered during laparotomy for other diseases.

　　1, Intestinal obstruction: Often a clinical manifestation of cystic-type duplicated anomalies that do not communicate with the main intestinal tract, especially cysts within the intestinal wall. Cysts protrude into the intestinal lumen, blocking the lumen and causing varying degrees of intestinal obstruction. Cysts are prone to become intussusception trigger points, presenting with acute symptoms of intestinal obstruction such as sudden vomiting, abdominal pain, and jam-like hematochezia. The age of onset in these cases is generally young, with Zhao Li and others reporting 13 cases of infants and young children under 2 years old, accounting for 61.5% from 5 to 9 months. As extraintestinal cysts gradually increase in size, they can compress the intestines to cause obstruction and can also be induced by gravity to cause intussusception, leading to severe abdominal colic, vomiting, cessation of defecation and flatus, and even the appearance of hematochezia, fever, thin pulse, and shock as symptoms of poisoning.

　　2, Gastrointestinal bleeding: Due to the presence of ectopic gastric mucosa or pancreatic tissue communicating with the main intestinal tract in the mucosal cavity of a duplicated anomaly, gastrointestinal bleeding occurs due to ulcer formation. Holcomb collected 101 cases of gastrointestinal duplication anomalies, 21 of which had ectopic gastric mucosa, including 11 cases (52%) occurring within ileal duplication anomalies. He believes that hematochezia is often the initial symptom of ileal tubular duplication anomalies, commonly seen in children over 1 year old. Clinically, it manifests as recurrent moderate hematochezia, and the color of the stool depends on the site and amount of bleeding. High bleeding with less volume results in black tarry stools, while low bleeding or more bleeding results in dark red or bright red hematochezia. Infants and young children often present with acute lower gastrointestinal bleeding, while older children mainly present with intermittent hematochezia accompanied by abdominal pain. Bleeding can often stop spontaneously, but it is prone to recurrence and can cause anemia. Occasionally, persistent massive hematochezia can lead to shock.

　　3. Abdominal mass and abdominal pain: About 2/3 of the cases can palpate a mass in the abdomen, and the cystic type anomaly is round or oval, smooth in surface with a cystic feeling, without tenderness. The mass boundary is very clear, with certain mobility. The tubular anomaly, because it has an outlet connected to the main intestinal tract, the secretions in the cavity can be discharged, so the chance of palpating the mass is less. If the outlet is not draining smoothly, the fluid in the anomalous intestinal cavity can accumulate in the abdomen and can be palpated as a string-like object. Once the outlet is unobstructed, the mass will shrink. The rapid growth of cysts due to increased tension of the cyst wall can cause abdominal pain. When the cyst hemorrhages or has inflammatory exudation due to trauma or infection, the mass rapidly increases in size, the abdominal pain intensifies, and is accompanied by abdominal muscle tension and tenderness. Once the cyst ruptures or perforates, it can lead to peritonitis.

　　4. Respiratory symptoms: In addition to abdominal symptoms, chest and abdominal duplication anomalies can also cause symptoms of respiratory or mediastinal compression. Sometimes, the main symptoms are chest symptoms, and the child may experience difficulty breathing, asthma, cyanosis, and mediastinal displacement. It is easy to be misdiagnosed as pneumonia or mediastinal tumor.

　　5. Coexisting anomalies: Intestinal duplication anomaly can coexist with intestinal atresia, malrotation of the intestines, and umbilical hernia. Sometimes, during emergency laparotomy due to coexisting anomalies, duplication anomalies are found. Chest and abdominal duplication anomalies often accompany cervical, thoracic hemivertebrae or fusion anomalies. A small number of patients with intestinal duplication anomaly present with abdominal masses, and children with malnutrition are more prone to palpating active masses due to weak abdominal walls.

　　Intestinal duplication anomaly is a spherical cystic cavity protruding outside the intestinal wall. Most of them are attached to the posterior or lateral side of the duodenum, and it is a clinical rare congenital developmental anomaly of the duodenum. This disease is a congenital disease with no special preventive measures.

　　1. Barium meal X-ray examination shows dilation, deformation, and high intestinal obstruction of the duodenum, and sometimes a mass shadow can be found.

　　2. Abdominal ultrasound examination; shows irregular duplication of the intestines on the left or right or front and back, and the intestines are irregular in shape.

　　The principle of postoperative dietary adjustment is:1. From less to more; 2. From thin to thick; 3. From simple to diverse. Summarized into eight characters, namely, step by step, less eating and more meals.

　　The specific practice is to start with a small amount of boiled water, and if there is no special discomfort, one can switch to fluid foods such as vegetable soup, fish soup, egg soup, thin porridge, and juice without pulp. The amount of food starts from 20-30 milliliters per meal and gradually increases to 200-300 milliliters. Each person's progress is different, and meals should be taken 5-6 times a day for comfort. In this way, after 1-3 days, one can switch to a low-fiber semi-liquid diet, such as thin porridge, paste made from flour, steamed egg paste, and various vegetable purees, with half a bowl to a bowl each time, 3-4 times a day, and some fluid foods can be added between meals. Generally, one can transition to soft foods such as rice porridge, bread, biscuits, apples, bananas, oranges, etc., 3-4 times a day, and it can gradually transition to normal diet about a month after surgery.

　　Surgery is the only treatment method for intestinal duplication malformation, and about 80% of cases are operated on due to acute abdomen. Even asymptomatic small intestinal duplication malformations should be surgically removed to prevent complications and the occurrence of cancer later in life.

　　1. Repeated malformation cystectomy: Some small intestinal repeated malformations have separate mesentery and blood vessels, and the cyst can be completely excised. For those with repeated malformations closely attached to the mesentery of the main intestinal tract, the surgeon should carefully search for the direct blood vessels nourishing the cyst between the main intestinal tract and the malformation cyst. Norris pointed out that when there is a clear gap between the main intestinal tract and the repeated malformation, it indicates that the malformed intestinal tract has its independent blood vessels, which originate from the anterior lobe (or posterior lobe) of the mesentery and extend to the anterior wall (or posterior wall) of the malformation cyst. Conversely, the blood vessels nourishing the main intestinal tract originate from the posterior lobe (or anterior lobe) of the mesentery and extend to the main intestinal tract through the posterior wall of the malformation. With careful identification and meticulous operation during surgery, the malformation cyst can be separated and excised without damaging the blood supply of the main intestinal tract.

　　2. Repeated malformation and main intestinal tract excision and anastomosis: Repeated malformations that share nutritional blood vessels and muscular walls with the main intestinal tract and those with repeated malformations within the intestinal wall are difficult to excise separately. If the range of the lesion is small (length

　　3. Repeated malformation mucosal stripping: The extensive range of repeated malformation affects most of the small intestine. The mucosal stripping of the malformed intestinal tract alone is performed for patients with short bowel syndrome due to intestinal resection. A longitudinal incision is made in the muscular wall along one side of the repeated intestinal tract to reach the submucosa, and the mucosa is sharply separated. An appropriate amount of normal saline is injected under the mucosa to facilitate mucosal stripping, and the mucosa is completely removed and excised. Then, part of the muscular wall of the repeated malformation is excised, and the incision margin is sutured or coagulated to stop bleeding. If the repeated malformation has a communication opening with the main intestinal tract, the mucosa of the repeated malformation is stripped off, and the connecting segment with the main intestinal tract is excised for intestinal anastomosis.