Duodenal fistula

　　1. Etiology of the disease

　　The formation of duodenal fistula has many causes, such as congenital developmental defects, iatrogenic injury, trauma, diseases, etc. Among diseases, it can be caused by duodenal lesions, such as duodenal diverticulitis, or it may be caused by lesions of adjacent organs of the duodenum, such as chronic colitis, gallstones, etc. One group of data reported that the most common cause of duodenal fistula is iatrogenic injury, followed by stones, open and closed injuries. Pathological factors such as tumors, tuberculosis, peptic ulcer disease, Crohn's disease, and radiation enteritis are less than 10%.

　　1. Congenital factors:True congenital duodenal fistula is extremely rare, with only a few case reports. Xu Minhua et al. reported 1 case of congenital gallbladder duodenal fistula, where the operation showed an abnormal channel between the duodenum and the gallbladder, and the mucosa at the transition was smooth without scar.

　　2. Iatrogenic injury:Duodenal fistula caused by iatrogenic injury generally exists between the duodenum and the common bile duct, and is more common in the lower end of the common bile duct during cholangiographic exploration with a rigid cholangiographic probe during bile duct surgery. Because the lower end of the common bile duct is anatomically narrow, excessive force during exploration may puncture the wall of the common bile duct and the duodenum, forming a fistula between the common bile duct and the duodenal papilla. Xue Zhaoxiang et al. reported 8 cases of fistula between the common bile duct and the duodenum after bile duct surgery, all of which were caused by difficult introduction of the bile duct probe due to inflammatory stricture of the common bile duct. It suggests that the use of probes during the exploration of the common bile duct during the operation should be cautious, and excessive force should be avoided to reduce iatrogenic injury. Moreover, when the T-shaped tube is used for the drainage of the common bile duct, if the position of the T-shaped tube is too low and the catheterization time is too long, the T-shaped tube may compress the duodenal wall, leading to ischemia, necrosis, and perforation, causing fistula between the common bile duct and the duodenum, which also belongs to iatrogenic injury. Fan Xianjun et al. reported 2 cases of duodenal perforation caused by T-shaped tube compression after bile duct surgery, where the T-shaped tube drainage orifice of the common bile duct and the duodenal perforation site formed a fistula in the duodenum. This suggests that the position of the T-shaped tube during the drainage of the common bile duct should not be too low, or a small piece of omentum should be placed between the T-shaped tube and the duodenum and fixed to prevent compression of the duodenum and secondary injury.

　　3. Gallstone Duodenal Fistula:It often occurs between the duodenum and the biliary tract system, and most of them are the result of perforation by gallstones. More than 90% of gallbladder-duodenal fistulas, common bile duct-duodenal fistulas, and gallbladder-duodenal-colonic fistulas originate from chronic cholecystitis and cholelithiasis. The internal fistulas are mostly located at the confluence of the bile, pancreas, and duodenum, and have more to do with biliary pancreas diseases. The repeated attacks of cholecystitis and cholelithiasis lead to adhesions between the gallbladder or bile duct and surrounding organs, which is the basis for the formation of internal fistulas later. On the basis of adhesions, the gallstones pressing on the gallbladder wall cause ischemia, necrosis, and perforation of the gallbladder wall and communication with another organ, forming an internal fistula. The neck of the gallbladder is one of the most common sites for perforation and fistula formation, which is related to the relatively small gallbladder duct, the strong contraction of the gallbladder after inflammation or stone stimulation, and the high pressure it bears. The most commonly affected organs during the repeated attacks of cholecystitis are the duodenum, colon, and stomach. When the biliary tract adheres to the duodenum due to inflammation, gallstones can compress the duodenum, causing necrosis, perforation, and spontaneous decompression and drainage of the intestinal wall, with gallstones being excreted into the duodenum, thus forming gallbladder-duodenal fistula, common bile duct-duodenal fistula, and gallbladder-duodenal-colonic fistula. This type of internal fistula formed by spontaneous decompression of the duodenum due to stone impaction, obstruction, and infection is often a special process of spontaneous stone excretion in the body or considered a complication of gallstones, and sometimes can cause gallstone intestinal obstruction.

　　4. Peptic Ulcer:The chronic penetrating ulcer of the duodenum often forms an internal fistula due to chronic inflammation perforating into adjacent organs, such as when the ulcer is located on the anterior or lateral wall of the duodenum, it can perforate into the gallbladder, forming a gallbladder-duodenal fistula. When the ulcer is located on the posterior wall of the duodenum, it can perforate into the common bile duct, causing a common bile duct-duodenal fistula. Duodenal ulcers can also perforate downward into the colon, causing a duodenal-colonic fistula, or a gallbladder-duodenal-colonic fistula. There are also reports of gastric-duodenal fistulas formed by penetrating pyloric ulcer, and cases of portal artery aneurysms closely adhering to the descending part of the duodenum, rupturing into the duodenum and causing massive hemorrhage, which is also a special type of duodenal fistula. Due to the early therapeutic effect of anti-secretory drugs on duodenal ulcers, duodenal fistulas caused by duodenal ulcers are now very rare in clinical practice.

　　5. Malignant tumors:Duodenal fistula caused by malignant tumors is also called malignant duodenal fistula, mainly caused by the infiltration and perforation of duodenal cancer into the liver flexure of the colon or the transverse colon, or the infiltration and perforation of the cancer in the liver area of the colon into the third and fourth segments of the duodenum. Hersheson collected 37 cases of duodenal-colonic fistula, of which 19 originated from colon cancer. In recent years, it has been reported in China that duodenal colonic fistula is a rare complication of colon cancer. In addition, Hodgkin's disease of the duodenum or colon, or cancer of the gallbladder can also cause duodenal fistula. With the increasing incidence of tumors, more and more reports on duodenal fistula caused by malignant tumors are emerging.

　　6. Inflammatory diseases:Internal fistulas can be formed due to the infiltration and perforation of chronic inflammation into adjacent organs. Inflammatory diseases include duodenal diverticulitis, Crohn's disease, ulcerative colitis, radiation enteritis, and specific intestinal infections such as abdominal tuberculosis, which can all cause duodenal colonic fistula or cholecysto-duodenal colonic fistula.

　　Second, pathogenesis

　　The pathological changes of congenital duodenal fistula: the bottom of the abnormal channel is gallbladder mucosa, the neck is duodenal glands, and 0.5cm above the gallbladder glands and duodenal glands can be seen to transition, proving it to be congenital abnormality. Wang Yuan and Tan Weilin (1988) reported 2 cases of congenital duodenal colonic fistula confirmed by surgery, both of which were adult females. The fistula occurred between the third part of the duodenum and the transverse colon. In view of the embryological research on the digestive system, the posterior 1/3 of the duodenum and the anterior 2/3 of the transverse colon are derived from the same mesentery. Therefore, from the perspective of embryological development, if there is an abnormality in the mesentery during the process of embryonic development, it is completely possible to form such fistulas.

　　6. Infection is the most common complication, and severe cases can lead to sepsis. Sepsis refers to the invasion of pathogenic bacteria or opportunistic pathogens into the blood circulation, and their growth and reproduction in the blood, leading to the occurrence of acute systemic infection. Sepsis accompanied by multiple abscesses and a long course is called septicemia.

　　5. Complications of water and electrolyte imbalance.

　　4. Hemorrhage and anemia are also common complications.

　　After the occurrence of duodenal fistula, whether the patient appears symptoms should vary depending on the different hollow visceral organs communicating with the duodenum. The consequences brought by the internal fistula to the body are also different due to the different organs communicating with the duodenum. The symptoms produced are often quite different due to the different organs damaged, such as duodenal biliary fistula, which is mainly characterized by biliary tract infection, so clinical symptoms are mainly liver damage; while duodenal colonic fistula is mainly characterized by gastrointestinal symptoms such as diarrhea, vomiting, and malnutrition.

　　1. Gastric duodenal fistula

　　Gastric duodenal fistula can occur between the stomach and the pylorus, transverse, and ascending parts of the duodenum, and almost all are due to secondary infection, adhesion, and subsequent perforation into the duodenal bulb adhered to it, or due to the formation of a local abscess after gastric perforation, followed by perforation into the transverse or ascending part of the duodenum.

　　After the formation of gastric duodenal fistula, there is little interference with the physiological function of the body, and generally there are no obvious symptoms. The vast majority of patients are covered by the clinical manifestations of fistula due to long-term severe ulcer symptoms; a few patients occasionally have gastric outlet obstruction.

　　2. Duodenal gallbladder fistula

　　The symptoms are very similar to cholecystitis, such as belching, nausea and vomiting, aversion to fatty foods, dyspepsia, sometimes with chills and high fever, abdominal pain, and the appearance of jaundice resembling cholangitis and cholelithiasis. Sometimes it presents as duodenal obstruction, and there may also be obstruction due to gallstones descending into the narrowed terminal ileum or ileocecal valve, presenting as acute mechanical intestinal obstruction symptoms. If caused by cancer, it is often in the late stage, with severe symptoms and rapid onset of cachexia.

　　3. Duodenal common bile duct fistula

　　It usually only presents with symptoms of peptic ulcer disease, and a few may develop acute suppurative cholangitis and be admitted to the emergency department.

　　4. Duodenal pancreatic fistula

　　Before the occurrence of duodenal pancreatic fistula, symptoms of pancreatic abscess or pancreatic cyst are often present, so it may be possible to inquire about a history of an upper abdominal mass. Secondly, most patients have severe gastrointestinal bleeding symptoms, which are difficult to diagnose before surgery. Berne and Edmondson believe that gastrointestinal pancreatic fistula has three related clinical courses, namely, abdominal mass after pancreatitis and sudden onset of severe gastrointestinal bleeding. One should be vigilant about the occurrence of fistula; when the abdominal mass disappears, it is often the day the fistula is formed. This experience can be referred to for diagnosis.

　　5. Duodenal colonic fistula

　　Benign duodenal colonic fistula often presents with upper abdominal pain, weight loss, fatigue, increased appetite, stools containing undigested food or severe diarrhea. Some patients may have vomiting, and the fecal smell in the vomit can be detected. The combination of past medical history has diagnostic significance. The time of fistula occurrence, according to statistics, ranges from 1 to 32 weeks, with the majority (more than 70%) of patients being diagnosed and operated on at least 3 months after the fistula occurs. The longer the fistula exists, the more sudden the symptoms become, and the more severe the consequences.

　　The most prominent symptom of congenital duodenal colonic fistula is diarrhea, which often appears at birth and there is no history of peritonitis, tumor, or abdominal surgery. Due to the low opening position of the congenital fistula on one side of the duodenum and the absence of obstruction at the distal end of the fistula, fecal vomiting and abdominal distension occur rarely. Without complications, there is no abdominal pain, and it is important to distinguish it from non-congenital benign duodenal colonic fistula.

　　If the duodenal colonic fistula is caused by infiltration and perforation of malignant tumors, in addition to the basic symptoms mentioned above, the condition is more severe, and the deterioration is faster. It often has the corresponding symptoms of malignant tumors at the same time.

　　6, Duodenal renal pelvis (ureter) fistula

　　In clinical practice, it can be first found that there is a perinephric abscess, that is, pain on the affected side of the lumbar, local mass, pain radiating to the thigh or testicle, positive psoas muscle irritation sign. Later, the urine may have bubbles, or it may be cloudy, or there may be food residue, as well as frequent urination, urgency, and dysuria, which are bladder irritation symptoms.

　　If there is a sudden onset of watery, purulent diarrhea accompanied by the disappearance of lumbar masses, it often indicates the occurrence of an internal fistula. At this time, the back pain is reduced, and there are often dehydration and hematuria. In addition, there are more prominent gastrointestinal symptoms, such as nausea, vomiting, and anorexia. It is very rare for renal calculi to be excreted through the anus, and those who fail to receive timely treatment present with chronic illness, fatigue, and anemia. Sometimes, it can cause significant sepsis. Patients always have urinary tract infection symptoms, and some patients have hyperchloremic acidosis.

　　Ning Tianchu et al. reported a case of congenital ureteral duodenal fistula complicated with urinary tract ascaridiasis. The patient had symptoms since the age of 4 and was diagnosed at the age of 18, with an estimated 400 worms excreted through the urethra. This case was confirmed and cured by surgery, and was reported in a case of a 5-year-old male with a right ureteral duodenal fistula with a history of excreting ascaris, also reported by the First Affiliated Hospital of Wuhan Medical College (1977). The patient was initially suspected of having a low-positioned intestinal fistula in the bladder, which is easy to misdiagnose. The surgery found that there was not only a fistula between the upper segment of the right ureter and the duodenum, but also a cross fistula 1cm below the lower pole of the right kidney connecting to the descending part of the duodenum, which was quite special. Therefore, the analysis of urinary tract ascaridiasis cannot be limited to the diagnosis of low-positioned bladder intestinal fistula.

　　Prevention is better than cure. Given the difficulty of treating duodenal fistula, how to prevent its occurrence becomes even more important. For elective surgery patients, the careful design of the preoperative surgical plan, good preoperative preparation, and meticulous surgical operation should not be ignored. Especially when performing B-Ⅱ type gastric resection, it is particularly important to pay attention not to over-force the resection of the ulcer scar of the duodenal bulb. In this case, it is better to adopt the method of ulcer旷置 to ensure safety. The duodenal stump should not be too long to avoid affecting healing. Pay attention to the suture technique, and the suture should not be too dense. The needle distance and edge distance should be 3mm. The knot should not be too tight, and the suture edge should be close enough, as too tight a knot may cause tissue tearing, leading to leakage and necrosis. If it is not possible to close the duodenal stump satisfactorily, temporarily inserting a catheter for decompression and drainage is a safe measure. If it is a radical gastrectomy for gastric cancer, soft rubber tubes or cigarette drains should be placed around the duodenal bed and stump to prevent the accumulation of lymph or bloody effusion, which may lead to infection and affect healing. However, attention should be paid to not placing the drain tube on the suture mouth of the stump, as this may compress and stimulate the wound, affecting healing. If B-Ⅱ type gastric resection is to be performed, it is recommended to use the proximal to the greater curvature antiperistaltic jejuno-gastric anastomosis as much as possible to reduce the complications of duodenal stump rupture caused by input loop obstruction.

　　Choose to do blood, urine, stool, routine, biochemical and electrolyte tests.

　　Chapter 1: X-ray Examination

　　Including abdominal透视, abdominal plain film, and gastrointestinal barium contrast.

　　1. Abdominal透视 and abdominal plain film:Sometimes there may be gas accumulation in the gallbladder, which is an indirect evidence for the diagnosis of duodenal fistula. However, it should be distinguished from gas gangrene caused by gas-producing bacteria. In the case of duodenal renal pelvis (ureter) fistula, the abdominal plain film can show air shadows in the renal area and non-radio-opaque stones (accounting for 25% to 50%).

　　2. Gastrointestinal barium contrast:Barium contrast examination of the gastrointestinal tract can provide direct evidence of the existence of internal fistula, and can show the size, course, whether there are branches and multiple fistulas of the duodenal fistula.

　　(1) Upper gastrointestinal barium contrast: The visible images include:

　　A. Stomach duodenal fistula, there is an anomaly in the pyloric canal of the stomach and a fistula in parallel with it.

　　B. Gastric duodenal fistula, there are barium and/or gas in the gallbladder or bile duct, and there are mucosal signs at the orifice of the fistula. The former is more diagnostic. In addition, the lack of contrast in the cholecystostomy is also one of the indirect evidence.

　　C. Duodenal colonic fistula, the colon is filled with barium.

　　D. Duodenal pancreatic fistula, barium enters the pancreatic area.

　　(2) Barium enema of the lower gastrointestinal tract: Barium can be found to enter the duodenum or biliary tract directly from the colon, and the correct diagnostic rate for duodenal colonic fistula can reach more than 90%. Double contrast barium enema of the colon can clearly show the location of the fistula, and combined with the observation of the mucosal patterns, it is helpful to differentiate between duodenal colonic fistula, jejuno-colonic fistula, colonic pancreas fistula, and colonic renal pelvis fistula.

　　3. Intra-venous pyelography:When performing this examination for patients with duodenal renal pelvis (ureter) fistula, due to the destruction of the function of the diseased kidney, it is often unable to show the location of the fistula, but the lesions of the diseased kidney can provide clues for the diagnosis of the fistula. Moreover, the treatment also needs to understand the function of the healthy kidney through angiography, so there is still significance in angiography.

　　Chapter 2: Ultrasound, CT, MRI Examination

　　It can display the location, scope, and morphological changes of bile duct stones inside and outside the liver, as well as the lesions of the gastrointestinal tract from different angles and parts. However, the diagnosis of duodenal fistula can only provide indirect diagnostic evidence, such as biliary gas, colonic fistula infiltration into the duodenum, and so on.

　　Chapter 3: ERCP Examination

　　Endoscopy can directly observe the fistula opening of the duodenal fistula, and at the same time inject contrast medium, which can show the course, size, and full view of the fistula, with a diagnostic accuracy of up to 100%, making it the most reliable diagnostic method for duodenal fistula.

　　Fourth, endoscopic examination

　　1. Colonoscopy:It can detect the orifices of abnormal gastrointestinal passages and make differential diagnoses. After the duodenoscope enters the duodenum, the mucosa appears as annular folds, soft and smooth, with papillae located on the longitudinal ridges on the inner side of the descending duodenum. Generally, the fistula is located above the papillary opening, and the shape is often irregularly star-shaped. There are no normal papillary shape and opening characteristics. When the fistula is covered by mucosa, it is not easy to be found. However, by inserting a catheter from the papillary opening, the catheter can be deflected back into the intestinal lumen. By inserting a catheter from above the fistula opening, the abnormal passage is visualized and diagnosed. At this time, the mirror is brought close to the fistula opening for observation, and bile or other fluids can be seen oozing out. Endoscopic examination of duodenal fistula should be differentiated from duodenal diverticula. Diverticula can also have openings near the duodenal papilla, but the edges are more even, the openings are often circular, and there are often food residues inside. After removing the residues, the bottom of the diverticulum can be seen. Inserting a catheter into the hole and then deflecting it back into the intestinal lumen, injecting contrast medium can cause it to be completely excreted. At the same time, contrast medium can be seen in the intestines without visualizing an abnormal passage. One report of 47 cases of common bile duct duodenal fistula, with 5 cases of concurrent duodenal diverticula, and 1 case where both the papilla and the fistula are located inside a large diverticulum. An immediate barium meal examination after endoscopic examination confirmed a large diverticulum on the inner side of the descending duodenum. Fiberoptic colonoscopy can accurately locate duodenocolonic fistula and observe the size of the fistula opening. Biopsy can determine the nature of the primary lesion, providing a basis for choosing the surgical method.

　　2. Laparoscopic examination:It can also be used as a means of diagnosis and treatment for duodenal fistula, and has a wide application prospect.

　　3. Cystoscopy:When suspected of having a duodenal renal pelvis (ureter) fistula, this examination can not only find signs of cystitis but also see bubbles or purulent debris excreted from the orifice of the ipsilateral ureter; or after injecting contrast medium through the catheter inserted into the ipsilateral ureter and taking a film, contrast medium can be found in the duodenum. Currently, the diagnosis mainly relies on retrograde pyelography, with nearly 2/3 of the patients being positive.

　　Fifth, bone charcoal powder test

　　After taking oral bone charcoal powder, black charcoal powder is excreted in the urine 15 to 40 minutes later. This examination can only confirm the existence of an internal fistula between the digestive tract and the urinary tract, but cannot determine the location of the fistula.

　　Many foods can have unexpected harmful effects on our intestines, so we should be more careful in our daily intake to avoid negative health effects caused by an imbalance.

　　These foods mainly include:

　　1. Meat:There is no fiber-rich fiber. If meat is not properly chewed, it is difficult to digest, leading to the proliferation of gut bacteria. Statistics show that in meat-consuming countries, the incidence of colon cancer is rising continuously.

　　2. Saturated fats:Saturated fats refer to animal fats and artificial fat cream. The accumulation of saturated fats alters the gut flora, increasing the content of bacteria that promote the conversion of bile salts into carcinogenic substances.

　　3. Gluten:Gluten will form a paste-like sticky substance, adhering to the inner wall of the intestines. It delays the passage of food, easily causes intestinal putrefaction, and also hinders the absorption of vitamin B group.

　　4. Sugar:It is conducive to the rapid proliferation of bacteria in the intestines, especially Escherichia coli, which is easy to form oxalic acid, which is a trigger for rheumatism.

　　5. Refined flour:It is easy to make the stool hard, especially when fruits and vegetables are lacking in the food structure, the condition of the eater will become more serious.

　　The treatment of duodenal fistulas is divided into surgical treatment and non-surgical treatment, and there is a great controversy on how to choose.

　　Firstly, non-surgical treatment:Considering that some duodenal fistulas can heal spontaneously and some can exist for a long time without symptoms, most scholars currently believe that only duodenal fistulas with clinical symptoms should be treated surgically, which is reasonable. One group of data reported that 186 cases of bile duct surgery were performed over 13 years, and 8 cases of common bile duct duodenal fistulas occurred after surgery (4.7%), of which 6 cases were cured after anti-inflammatory and nutritional support treatment (75%), and only 2 cases were cured after non-surgical treatment failed and changed to surgical treatment.

　　Non-surgical treatment includes correcting water and electrolyte disorders, selecting effective and sufficient antibiotics to control infection, active intravenous nutritional support, and growth hormone can be added if necessary. Close observation of vital signs and abdominal conditions should be made. If the clinical manifestations do not improve, surgical treatment should be considered.

　　Secondly, surgical treatment:Abdominal exploratory surgery is performed under active antishock and monitoring, including intravenous fluid infusion (establishing two intravenous access points), blood transfusion, and anti-infection.

　　1. Gastric duodenal fistula:According to the location and size of the gastric ulcer, the resection of most of the stomach and the proper closure of the duodenal fistula have satisfactory therapeutic effects. If the fistula is located in the transverse and ascending parts, inflammation and adhesions are often severe, and the surgery should be particularly careful in anatomical dissection and exposure of the fistula to avoid injury to the superior mesenteric artery or inferior vena cava. Webster (1976) recommended that before anatomical dissection and exposure of the duodenal fistula, the superior mesenteric artery and vein should be freed and controlled, which can both avoid accidental injury to the blood vessels during surgery and reduce the tension of the repair of the duodenal fistula.

　　2. Duodenal gallbladder fistula:During anatomical surgery, attention should be paid to the location of the duodenal gallbladder fistula. There are direct internal fistulas with short and large fistula orifices, as well as indirect internal fistulas with long and narrow fistulas. Due to the abundant adhesions, the anatomical relationship is not easy to identify, so it is advisable to first incise the gallbladder, explore the location and direction of the fistula orifice, and carefully free it to avoid injury to the duodenum and other organs. After the anatomical surgery is completed, excise the scar tissue at the edge of the duodenal fistula and then suture the duodenal wall transversely. If there is concern about the firmness of the suture, it can be covered with jejunal serosa or seromuscular sheets. Then, examine whether the common bile duct is patent, place a T-tube for drainage, and finally excise the gallbladder. For those with large fistula or severe inflammatory edema, corresponding duodenal or gastric fistula surgery should be performed for duodenal decompression and drainage to facilitate the healing of the fistula. Abdominal drainage should be placed after the operation.

　　3. Duodenal common bile duct fistula: Simple duodenal common bile duct fistulas caused by complications of duodenal ulcers can be cured by non-surgical treatment. For cases with frequent cholangitis or refractory duodenal ulcers, surgical treatment is required, otherwise the internal fistula cannot be cured spontaneously. A better surgical method is the vagotomy, subtotal gastrectomy, and gastrojejunal anastomosis. The closure of the duodenal stump can be performed using the Bancroft method. No additional treatment is needed for the duodenal common bile duct. After the gastric content is rerouted, the fistula can close spontaneously. If there are gallstones or cholangitis, it is not advisable to use the above surgical methods. It is necessary to first explore the common bile duct, and gallstones, cholangitis, food residue, etc. should be cleared and decompressed, and a T-shaped tube should be placed for drainage; or after the duodenum and common bile duct are separated, the fistula holes in the duodenum and common bile duct should be separately repaired, and a T-shaped tube should be placed for drainage, and a duodenal stoma should be made for decompression. After the gallbladder is resected, an abdominal drain should be placed.

　　4. Duodenal pancreatic fistula:The key lies in the early and proper drainage of pancreatic abscess or cyst, timely relief of duodenal distal obstruction and nutritional support, so that all duodenal pancreatic fistulas can be cured spontaneously. Pancreatic juice erosion of the intestinal wall blood vessels can cause severe gastrointestinal bleeding. If non-surgical treatment is ineffective, surgery should be performed in a timely manner, the duodenal wall is incised, and the bleeding points are ligated with non-absorbable sutures.

　　5. Duodenal colonic fistula:Starzl et al. reported a case of duodenal colonic fistula caused by subphrenic abscess due to ulcer perforation, which was cured spontaneously after the subphrenic abscess was drained. There are also reports of fistulas caused by tuberculosis being cured after anti-tuberculosis treatment, but the majority of duodenal colonic fistulas (including congenital) require surgical treatment. Due to the involvement of the colon, sufficient bowel preparation and improvement of the patient's overall condition should be noted before surgery.

　　Benign fistulas can be treated by simple fistula resection, followed by duodenal and colonic repair, and sealing the fistula orifice. If there is significant scarring or adhesions around the fistula orifice, fistula resection and intestinal anastomosis should be performed. After the internal fistula located in the third part of the duodenum is resected, there may be a large defect in the duodenal wall, so attention should be paid to the relaxation of the Treitz ligament and the attachment of the right mesenteric vessels to the retroperitoneum to ensure that the repair site is tension-free. If necessary, the serosa or seromuscular layer of the proximal jejunum loop can be used to cover and repair the defect in the duodenal wall. For those caused by duodenal ulcers, if the patient's condition permits, it is advisable to perform subtotal gastrectomy at the same time. Congenital fistulas have the possibility of multiple fistulas, so careful and meticulous exploration should be performed during surgery to prevent any omissions.

　　In cases of malignant internal fistula caused by colon cancer infiltrating the duodenum, radical or palliative surgery should be chosen according to the specific situation.

　　(1) Radical surgery: Callagher has introduced the use of extended right hemicolectomy to treat duodenal colonic fistula caused by malignant tumors located at the right colic flexure of the colon. So-called extended right hemicolectomy refers to the standard right hemicolectomy plus partial pancreaticoduodenectomy, and then reconstruct the digestive tract. This includes performing choledochojejunostomy (or cholecystojejunostomy), pancreaticojejunostomy (all need to be cannulated with rubber or plastic tubes for drainage), gastrojejunostomy, and ileotransverse colon anastomosis.

　　(2) Palliative surgery: For those who cannot be resected, palliative surgery can be performed. This is to cut off the pylorus of the stomach, transverse colon, and distal ileum separately, then seal the distal ends of the stomach and ileum, and then perform anastomosis between the stomach and jejunum, and between the ileum and transverse colon, and then anastomosis with the ileum output loop and the proximal transverse colon. Whether it is radical or palliative surgery, abdominal drainage is required during surgery.

　　6, Duodenal renal pelvis (ureter) fistula

　　(1) Draining abscesses: In cases with perinephric abscess or retroperitoneal abscess, timely drainage is required.

　　(2) Exclusion of urinary tract obstruction: If there is obstruction in the diseased kidney or ureter, measures should be taken to drain. Options include retrograde catheterization of the diseased ureter or temporary nephrostomy. After the above treatment, a few fistulas can close and heal spontaneously.

　　(3) Nephrectomy and fistula repair: If the diseased kidney has lost its function or is uncontrollable infection, while the healthy kidney function is good, the resection of the diseased kidney can be considered to facilitate the radical treatment of the internal fistula. Abdominal incision is used to facilitate the simultaneous repair of the intestinal fistula. Due to chronic inflammation, there are many adhesions around the kidney, and the anatomical relationship is unclear, so full estimates and corresponding preparations should be made for the difficulties that may be encountered during surgery, including strict intestinal preparation. After the duodenal fistula side is resected, suture repair is performed, and duodenal decompression is done. Abdominal and peritoneal drainage are performed.

　　(4) Duodenal ureteral fistula often requires the complete resection of the diseased kidney and ureter. If only the kidney and ureter above the internal fistula are resected without resecting the distal ureter, the fistula can persist. Occasionally, if the lesion of the ureter is very limited and the kidney has not been seriously damaged, it may be considered to perform local resection of the diseased ureteral side followed by end-to-end anastomosis.

　　Postoperative observation of the condition should be strict, continue to use effective antibiotics, and provide duodenal decompression.