Iatrogenic bile duct injury

　　First, etiology

　　Moorhead analyzed the causes of 958 cases of bile duct stenosis and found that 34% of surgical injuries to patients were due to excessive bleeding during surgery and blind clamping ligation; 22% were due to variations in the gallbladder triangle or significant local inflammation; 21% were due to ligation of the common bile duct; 5% occurred in more difficult partial gastrectomies. Liang Lijian reported 20 cases of bile duct injury, of which 1 occurred in an emergency operation, and another 1 in LC due to unclear local adhesion and anatomy. Other bile duct injuries occurred under normal anatomy and not difficult conditions. For example, in one case, due to the T-shaped tube draining hemorrhagic fluid, a second laparotomy was performed for ligation of bleeding in the common bile duct, and postoperative T-shaped tube angiography showed significant stenosis at the distal end. In another case, during cholecystectomy, a fine needle puncture went through the common bile duct without T-shaped tube drainage, leading to postoperative bile leakage. In 2 cases, due to bleeding from small blood vessels during surgery, suture needles respectively pierced the common hepatic duct and right hepatic duct during hemostasis, causing biliary peritonitis. Johnston attributed the causes of bile duct injury to three points: dangerous pathology, dangerous anatomy, and dangerous surgery, that is, anatomical factors, pathological factors, and technical factors.

　　1. Anatomical factors

　　Variations in the Calot triangle are very common, mainly including the appearance of the right accessory hepatic duct and abnormal junction of the cystic duct with the extrahepatic bile duct. If calculi are impacted, it further increases the complexity of the anatomy. In addition to the variations of the bile duct, there are also abnormal courses and branches of the hepatic artery and portal vein. It is easy to cause bleeding if they are not identified clearly during surgery, and it is easy to cause biliary tract injury when dissecting the Calot triangle in a pool of blood. Therefore, being familiar with biliary tract variations is the key to surgical success.

　　2. Pathological factors

　　When acute suppurative cholecystitis, gangrenous cholecystitis, chronic atrophic cholecystitis, and Mirizzi syndrome occur, the gallbladder and surrounding tissues become edematous, congested, inflamed, and have internal fistulas, making it difficult to recognize the normal anatomical relationship. This increases the difficulty of surgery and also increases the possibility of accidents. In addition, due to the inflammation and adhesion of surrounding tissues, anatomical variation of the liver and duodenum, and the shortening of the distance between the bile duct and the ulcer, injury to the bile duct, even the portal vein, may occur during subtotal gastrectomy.

　　3. Technical factors

　　The surgeon's experience and serious attitude are important factors for the success of cholecystectomy. In addition, the anesthetic condition during surgery, the lighting, exposure, and whether the patient is obese or not are all factors that affect the success of surgery.

　　In addition to the above reasons, the technical conditions of the laparoscopic instruments themselves are also potential risk factors for biliary tract injury during laparoscopic cholecystectomy (LC). Firstly, the surgeon is affected by the two-dimensional imaging system and unclear vision. Secondly, the surgical operation is only completed by instruments and cannot be touched by hand, lacking experience. In addition, the light source and lens are from bottom to top. When the gallbladder neck is pulled to the right side, the Calot triangle area is obscured, making the angle between the cystic duct and the common bile duct smaller, which is easy to ligate the common bile duct instead of the cystic duct. It is more likely to occur when the cystic duct is thick and short or runs parallel to the common bile duct. In addition, delayed high-grade biliary strictures after LC are also very common, which are related to the electrical thermal injury to the extrahepatic bile duct caused by the use of electrocautery and electrocoagulation.

　　II. Pathogenesis

　　1. According to the time of injury

　　It is divided into early biliary tract injury and late biliary strictures.

　　(1)Early biliary tract injury: Refers to a series of clinical manifestations related to biliary tract injury that occur during surgery or before hospital discharge. Biliary tract injury found during surgery, such as bile leakage, open biliary tract, or ligation, is relatively rare. The vast majority of biliary tract injuries are discovered during the observation period after returning to the ward. Due to early detection, generally speaking, the treatment is relatively easy and the prognosis is good.

　　(2)Advanced bile duct stricture: Symptoms usually appear late, mostly due to bile duct stricture. Most of the lesions are related to local bile duct ischemia, or due to local tissue inflammatory changes and fibrosis after bile leakage, leading to gradual narrowing of the bile duct. From bile duct wall injury to the appearance of local stricture symptoms usually takes 3 months to 1 year, and sometimes even up to 3 to 5 years. It is manifested as progressive jaundice and recurrent cholangitis. Diagnosis is relatively difficult, complications of repair surgery are numerous, mortality rate is high, and treatment effects are unsatisfactory.

　　2. Classification according to the characteristics of injury

　　It is divided into bile leakage bile duct injury, obstructive bile duct injury, and false passage injury at the lower end of the common bile duct.

　　(1)Bile leakage bile duct injury: This is caused by bile duct tears, transverse cuts, necrosis, perforation, and leakage at the residual bile duct stump due to various reasons. If bile leakage is significant, it can be found during surgery. If the leakage amount is small or the surgeon is negligent in inspection, the patient may present with cholestatic peritonitis several days after surgery, leading to suspicion and treatment.

　　(2)Obstructive bile duct injury: This includes the incorrect ligation or clamping (transverse or partial transverse) of extrahepatic bile ducts and accessory right hepatic ducts, as well as mechanical injuries. Electrical burns during laparoscopic cholecystectomy (LC) can cause local ischemia, leading to secondary bile duct stricture. Most symptoms appear several days or months after surgery, with patients mainly presenting with progressive jaundice, recurrent cholangitis, and other symptoms.

　　(3)False passage injury at the lower end of the common bile duct: This type of injury often occurs due to the forced passage of the Bakes dilator through the lower end of the common bile duct during the exploration of the common bile duct, leading to a false passage between the common bile duct and the duodenum. It is generally not easy to confirm during surgery unless there is significant bleeding. Postoperative local infection and ulceration can lead to an internal fistula between the bile duct and the duodenum.

　　3. Classification according to the site of injury

　　In order to better design treatment plans and facilitate the evaluation of treatment effects, Bismuch classified patients with advanced bile duct stricture according to the site of injury as follows: Ⅰ more than 2cm from the origin of the common bile duct towards the distal end; Ⅱ within 2cm from the origin of the common bile duct towards the distal end; Ⅲ convergence of the left and right hepatic ducts; Ⅳ left hepatic duct or right hepatic duct; V branching point of the left and right hepatic ducts.

　　(1)The biliary tract is the secretory and excretory channel of the liver, which has important physiological functions in the normal communication with the intestines, and it is of great significance for digestion, absorption, and overall metabolism. Iatrogenic bile duct injury can be roughly classified into three types: bile leakage, obstructive jaundice, and postoperative bile duct stricture:

　　①During cholecystectomy, it is possible to mistakenly cut a part or all of the bile duct, leading to localized or diffuse cholestatic peritonitis due to bile leakage after surgery, which ultimately results in the formation of extrahepatic bile fistula. This type of injury is often not discovered at the initial stage unless the surgeon carefully inspects. This is because during surgery, factors such as anesthesia and surgical trauma temporarily inhibit the liver's excretion of bile, reducing the pressure of bile secretion. At the time of surgery, only a small amount or no obvious bile leakage is observed, which does not attract the surgeon's attention and thus loses the opportunity for immediate treatment. As the liver's bile secretion function gradually recovers after surgery, clinical symptoms of peritonitis or bile leakage from the drainage site may appear.

　　② Obstructive jaundice is caused by acute biliary obstruction due to clamping or suturing of the common hepatic duct or common bile duct during cholecystectomy. It manifests as progressive and worsening jaundice of the whole body in the early postoperative period, followed by deep yellow urine, grayish stools, and general pruritus and other symptoms.

　　③ Postoperative bile duct stricture is the adverse consequence of bile duct injury during cholecystectomy. Symptoms appear slowly, often with abdominal pain, intermittent fever, and jaundice weeks or months after surgery. As the course progresses, during the intercritical period of cholangitis, jaundice does not subside completely. This is often due to bile leakage or injury, leading to intrahepatic bile stasis or after postoperative drainage, the lower abdominal area and the surrounding tissue around the bile ducts are chemically stimulated by bile acids, causing progressive fibrosis and hyperplasia, leading to thickening of the bile duct wall and narrowing of the lumen, and it worsens gradually due to the recurrence of cholangitis.

　　(2) The harm caused by these changes is:

　　① It disrupts the communication between the bile and intestines, leading to digestive and absorptive disorders, and brings about systemic consumption.

　　② Biliary peritonitis causes systemic internal environment disorder.

　　③ The formation of bile leakage causes water and salt, acid-base balance disorders, and due to its not being a direct bile duct drainage pathway, it is very easy to cause recurrent uncontrolled suppurative cholangitis due to poor drainage. These are all major causes of early death in patients after injury.

　　④ Acute complete biliary obstruction, postoperative bile duct stricture, and recurrent biliary infection all lead to damage to the liver parenchyma. If not treated promptly or treatment fails, it can develop into biliary cirrhosis and portal hypertension over time, making treatment more difficult and the prognosis very serious.

　　If bile leakage is not controlled, complications will soon arise, which can form cholangitis and abscess. Chronic cholangitis caused by stricture can develop into multiple intrahepatic abscesses and sepsis. Whether the first treatment after bile duct injury is appropriate has a great impact on the prognosis of the patient and the difficulty of subsequent surgery, so it should be handled with great caution. The principles and timing of the first treatment should be strictly controlled to prevent the occurrence of recurrence and severe complications.

　　1. Early bile duct injury

　　1. Bile leakage:

　　It is common in patients with partial or complete transection of the common hepatic duct, bile duct, or common bile duct, or in patients with bile duct stump leakage after surgery. Due to anesthesia during surgery and the impact of surgical trauma, the secretion of bile juice in patients is often suppressed, so when the incision is small and bile leakage is less, it is often not easily discovered by the surgeon, resulting in the loss of the opportunity for intraoperative repair. Postoperatively, patients may develop biliary ascites, with bile-like fluid flowing out from the abdominal drain tube. If infection occurs, it may present as cholangitis, with bile draining from the abdominal drain tube. It needs to be differentiated from small accessory hepatic duct injuries on the gallbladder bed. Small accessory hepatic duct injuries usually stop spontaneously within 3 to 5 days, while bile duct injuries have a large bile drainage volume and a long duration. If the drain tube is placed improperly, drainage failure may occur, leading to peritonitis, intestinal paralysis, and in severe cases, peritoneal abscess.

　　2, Obstructive jaundice:

　　Early progressive jaundice often occurs in partial or complete ligation or suture of the common bile duct or hepatic duct, with patients commonly experiencing discomfort in the upper abdomen and deep yellow urine.

　　3, Biliary duct duodenal fistula:

　　Generally, a large amount of malodorous fluid containing brownish-yellow turbid flocculent matter, and sometimes even food residue, flows out from the T-shaped tube on the 7th day after surgery. The T-shaped tube drainage volume can reach 1000 to 1500 ml, and patients often have chills and high fever, but jaundice does not usually occur or only mild jaundice is present.

　　4, Infection:

　　Obstruction of the bile duct, poor bile drainage, bile stasis, bacterial proliferation causing acute biliary tract infection, leading to symptoms such as abdominal pain, fever, jaundice, and so on. Patients with bile leakage may also develop diffuse peritonitis, subdiaphragmatic abscess, pelvic abscess, and other complications, and may also appear symptoms of intestinal paralysis and other toxic symptoms.

　　Second, advanced biliary stenosis

　　Symptoms often appear within 3 months to 1 year after the first surgery and are often misdiagnosed as residual stones within the liver, hepatitis, capillary cholangitis, and other conditions. Clinically, there are the following signs.

　　1, Recurrent biliary tract infection:

　　The pathological basis of advanced biliary stenosis is progressive biliary stenosis, which leads to poor drainage and bile retention. This can induce biliary tract infection, and in severe cases, sepsis or even Charcot's pentad may occur. After treatment with antibiotics, the condition may improve, but due to the persistence of the basic pathological basis, it often recurs. Many patients are misdiagnosed as having residual stones within the liver.

　　2, Obstructive jaundice:

　　Biliary stenosis is a progressive and persistent lesion. In the early stage, jaundice is generally absent. However, with further narrowing of the stenotic orifice, obstructive jaundice appears and gradually worsens, accompanied by stones and infection, making the symptoms more obvious.

　　3, Biliary cirrhosis:

　　Due to long-term poor drainage, bile stasis, and increased pressure within the bile duct, bile leakage into the liver cells after the bile ductules rupture causes the proliferation of fibrous connective tissue, the变性 and necrosis of liver tissue, eventually leading to biliary cirrhosis and portal hypertension. Clinically, symptoms such as enlargement of the liver and spleen, ascites, jaundice, liver function damage, coagulation mechanism disorders, and malnutrition may occur. Sometimes, patients may also experience massive upper gastrointestinal bleeding due to esophageal varices at the gastroesophageal junction.

　　4, Biliary calculi:

　　Biliary stenosis causing bile stasis and recurrent biliary tract infections are high-risk factors for the formation of stones, while the stones that have formed often cause obstruction and infection, forming a vicious cycle. This leads to recurrent attacks of bile duct stones.

　　The occurrence of iatrogenic biliary tract injury is often described as 'accidental', caused by a variety of factors, and prevention is of great importance. Its occurrence is not just a 'momentary' deviation during surgery, but rather the result of a comprehensive factor in the entire diagnosis and treatment process. In the issue of preventing biliary tract injury, emphasizing technical training, technical management, and overcoming negligence is always very important. Laparoscopic cholecystectomy (LC) provides a new technical means, and due to the application of special energy sources (electrocoagulation, laser, microwave), it has increased the characteristics of concealment and protraction in pathological changes after injury, posing new requirements for clinical work. Preventing biliary tract injury is also a top priority. The principles for a safe cholecystectomy are as follows:

　　First, the basic requirements

　　1. A comprehensive preoperative diagnosis and full understanding of the gallbladder pathology, and formulate a relatively comprehensive surgical plan.

　　2. Arrange for surgeons and assistants who are capable of performing the surgery.

　　3. Choose a suitable surgical incision with good exposure.

　　4. Always be vigilant about the possibility of bile duct injury, carefully identify the relationship between the cystic artery, cystic duct, and common bile duct, and flexibly use the technical operations of antegrade and retrograde cholecystectomy, adhering to the戒律 of not arbitrarily clamping, tying, or cutting any structure.

　　5. Laparoscopic cholecystectomy should be performed on the basis of certain conditions and training, and the indications should be strictly controlled.

　　Second, when encountering unexpected bleeding or other events, calm and proper emergency handling should be done.

　　In cases where the bile duct is not well exposed or cannot be clearly identified, disorganized hemostasis during accidental bleeding is one of the two major causes of intraoperative bile duct injury.

　　2. Thoroughly expose the cystic duct and carefully dissect the gallbladder triangle. The cystic duct should be freed first, lifted with a silk thread without tying or cutting it off, and finally tied and cut off after the anatomical relationship is indeed identified. If the gallbladder triangle is severely adhered and the cystic duct, gallbladder artery, or common bile duct cannot be distinguished, the method of resection from the gallbladder bottom should be adopted.

　　1. Do not be in a hurry when bleeding occurs during surgery, and ensure good exposure to see the bleeding point and stop the bleeding properly. If there is a lot of bleeding and the bleeding site is not clear, do not clamp blindly. You can pinch the hepatic artery and portal vein at the small网膜 hole with your fingers to control the bleeding, remove the accumulated blood, and let the surgeon stop the bleeding. At this time, do not clamp aimlessly in the blood pool. It should also be avoided that at this time, neither the surgeon nor the assistant helps to expose and remove the blood, but both go to be busy clamping.

　　3. If it is a laparoscopic cholecystectomy, it should be transferred to an open surgery in a timely manner.

　　Third, for difficult cholecystectomy

　　Sometimes, due to chronic cholecystitis, the gallbladder atrophies into a mass, and the anatomical structure of the gallbladder triangle is difficult to distinguish. At this time, a cut can be made at the bottom of the gallbladder, with the finger in the gallbladder as a guide, to separate downwards. To prevent injury to the common bile duct, the common bile duct can be directly opened, and a bake dilator inserted under its guidance to identify the relationship with the cystic duct. Do not blindly separate and cut. If the cystic duct still cannot be handled, partial cholecystectomy or subserosal cholecystectomy should be performed for safety.

　　During surgery, the cooperation of intraoperative cholangiography or intraoperative B-ultrasound can help understand the anatomical relationship of the bile duct, and prevent injury to the bile duct. Especially for patients with multiple bile duct surgeries and severe extracorporeal bile duct adhesions, these preparations should be made before surgery.

　　Patients with bile duct stenosis often have elevated serum alkaline phosphatase levels, and serum bilirubin levels fluctuate with symptoms, but usually remain below 10mg/dl. During an acute cholangitis attack, blood cultures often show positive results.

　　For suspected cases, necessary auxiliary examinations should be conducted, with imaging examinations playing a very important role. Postoperative patients with suspected bile duct injury should undergo ultrasound (BUS), computed tomography (CT), percutaneous liver bile duct造影 (PTC), endoscopic retrograde cholangiopancreatography (ERCP), magnetic resonance cholangiopancreatography (MRCP), and T-tube cholangiography, among others, to clarify the diagnosis. BUS and CT are non-invasive examination methods that can understand the liver shape, the extent of bile duct dilation, range, and signs of gallstones. However, when scar formation occurs around the bile ducts above the hilum of the liver, their application is limited. ERCP is a minimally invasive造影 method that injects contrast material through the Vater ampulla retrogradely into the biliary tract system, allowing for a clear understanding of the internal structure of the bile ducts. The disadvantage is that it can only understand the lower parts of the obstruction. In patients who have undergone a subtotal gastrectomy or bile-enteric diversion surgery, its application is limited. PTC is the best radiological examination for bile duct injury, which can completely display the narrowed bile ducts and bile ducts above the narrowing, fully understand the condition of the bile ducts above the obstruction, and can perform percutaneous liver穿刺置管引流术 (PTCD) for jaundice patients to reduce jaundice and improve the patient's preoperative condition. However, it is contraindicated in patients with acute cholangitis and can cause bile leakage, hemorrhage. In patients with small bile ducts, puncture is not easy to succeed. Some authors emphasize that before reoperation in patients with bile duct injury, it is necessary to perform PTC and MRCP examinations. Magnetic resonance cholangiopancreatography (MRCP) is a new type of examination, a three-dimensional stereoscopic image, which can display the location of bile duct stenosis, the extent of bile duct dilation, and whether there is gallstone, due to its simplicity and non-invasiveness, it has the tendency to replace PTC and ERCP. Dwerry-House et al. believe that MRCP can reduce 3/4 of unnecessary ERCP examinations. T-tube cholangiography utilizes the T-tube or abdominal sinus tract left by the previous surgery for bile duct造影, which can display bile duct lesions but does not fully display intrapulmonary bile ducts. For patients with bile duct stenosis who need reoperation, selective hepatic artery造影 can understand the blood supply of the bile duct, which can improve the success rate of reoperation.

　　First, what foods are good for the body after iatrogenic bile duct injury:

　　1, Lean meat and freshwater fish are recommended. Fish has low fat content but contains high-quality protein. Other low-fat, high-protein meats include freshwater shrimps, chicken, and rabbit meat.

　　2, It is best to cook with vegetable oils, such as corn oil and peanut oil. The main cooking methods are stewing, braising, and steaming, with a light taste being the main approach. Skimmed milk is recommended for dairy drinks.

　　3, Fruits are best eaten with a high vitamin A content: oranges, almonds, bananas, apples, walnuts, peanuts, hawthorn, and umeboshi. Apple juice, pear juice, and beet juice can also be consumed.

　　4, Whole grains, fresh vegetables, garlic, onions, mushrooms, black fungus, corn silk, and bran can lower cholesterol and are recommended for consumption. Vegetables rich in vitamin A or vitamin K can be eaten, such as broccoli, which is rich in vitamin K. Vegetables rich in vitamin A include carrots, tomatoes, spinach, lettuce, soybeans, and green peas.

　　Second, what foods should not be eaten for iatrogenic bile duct injury:

　　1, Do not eat foods with high cholesterol, such as animal hearts, livers, brains, intestines, as well as yolks, salted eggs, fish roe, and crab roe. It is recommended to eat less high-fat meats: such as fatty meat. At the same time, seafood should be eaten less.

　　2, Avoid eating fruits that have not been cleaned thoroughly, to prevent ingesting ascaris eggs. It is strictly forbidden to eat fried fruits such as fried potato chips and fried bananas.

　　3, Do not eat vegetables that are not clean, contain pesticide residues, or have ascaris eggs, and eat less spicy vegetables: such as rapeseed. It is recommended to eat less: such as soy milk, bean cake, etc.

　　First, treatment

　　The principles and techniques for treating bile duct injury should be determined according to the time, location, and type of injury.

　　1, Biliary duct injury diagnosed during surgery

　　It is most ideal to detect and treat it in time during surgery, because the success rate of tissue health repair is high, and it also avoids the difficulties, passivity, and risks of reoperation.

　　(1)Accidental ligation of the extrahepatic bile duct without cutting: generally, it is only necessary to remove the ligature. However, if the ligation is too tight and too long, or if it cannot be confirmed that the bile duct is patent after relaxation, then consider incision and insertion of T-tube drainage to prevent necrosis or stricture. If the bile duct wall has blood supply obstruction and necrosis, the segment of the bile duct can be resected and end-to-end anastomosis or biliary-enteric anastomosis can be performed.

　　(2)Cutting injury of extrahepatic bile duct: end-to-end anastomosis should be performed for cutting injuries, the side wall of the common bile duct (gallbladder) should be incised and a T-tube placed for drainage, and the lateral peritoneum of the duodenum should be freed to reduce the tension of the anastomosis. The anastomotic technique requires good ends, even needle spacing, and generally uses 3-0 suture thread. If the injury site of the bile duct is high and end-to-end anastomosis is difficult, or if the resected segment of the common bile duct is too long, and the tension is still high after freeing the lateral peritoneum of the duodenum, then Roux-en-Y biliary-enteric anastomosis or biliary duodenal anastomosis should be performed, and the support frame drainage should be placed for more than 6 months after surgery. Roux-en-Y anastomosis has a better effect.

　　(3)Rupture injury of extrahepatic bile duct: most of the injuries caused by forceful traction during surgery are longitudinal lacerations. If the incision is not wide or the injured bile duct is less than 50% of the diameter, the wall of the injured bile duct should be sutured transversely, and T-tube external drainage should be placed. When placing it, a new incision should be made above or below the injury site, and the long arm of the T-tube should be placed to support the suture site. Pay attention not to insert the T-tube from the original injury site to avoid postoperative stricture. If there is a large defect but the bile duct still has some connection, tissues such as the gallbladder wall with blood supply, jejunal wall, ileal wall, gastric serosa, umbilical vein, and round ligament of the liver can be used for repair, and internal support drainage surgery should be added. The serosal epithelial tissue can better tolerate the erosion of bile, has strong repair ability, and has a good effect.

　　(4)Injury to the lower segment of the common bile duct: appropriate treatment should be carried out according to the specific situation upon discovery:

　　①The tract is small, with no obvious bleeding, only T-tube drainage and peritoneal drainage are placed;

　　②The tract is relatively large, the head of the pancreas and duodenum are flipped to the left and medially, and the tract is explored. If the tract leads to the parenchyma of the pancreas or intestines, there is no bleeding or bleeding has stopped, the common bile duct is placed for T-tube drainage, and the head of the pancreas and duodenum are placed for suture drainage. After surgery, it is necessary to maintain the patency of the drainage, and generally, most patients can recover. Due to the complex anatomy of the head of the pancreas and duodenum, it is best to avoid complex surgical procedures.

　　2. Early postoperative diagnosis of bile duct injury

　　When bile duct injury is found early postoperatively, the original surgeon should be asked to recall the surgical process, and auxiliary examinations such as abdominal puncture and BUS should be performed to assist in diagnosis. Biliary obstructive injury is mostly due to accidental ligation of extrahepatic bile ducts, and early repair or release should be performed as soon as possible. For patients with bile leakage as the main manifestation, it depends on the condition of drainage. If the amount of bile leakage is small and there are no symptoms of peritonitis, conservative observation can be performed. If the drainage is poor or bile peritonitis has already occurred, active surgical exploration should be performed. For patients with injury within 72 hours and good general condition, primary repair can be performed. For those with injury more than 72 hours, due to secondary infection, local tissue inflammation and edema are obvious, and generally, bile duct drainage is performed as a transitional treatment, followed by radical treatment 2～3 months later. Or place an effective double-lumen drainage tube at the most appropriate position, add a lavage tube, and perform 24-hour continuous lavage and negative pressure aspiration to promote the early regression of inflammation. It is dangerous to perform radical surgery by force at this time, and violating this principle often leads to serious complications.

　　3. Late bile duct stricture

　　Bile duct stricture occurs months or years after surgery, and the patient cannot be diagnosed for a considerable period of time after the onset of symptoms. Due to the long course of the disease, patients often have liver function damage and poor general condition. Therefore, the treatment of late bile duct stricture is complex, and in addition to surgical treatment, the selection of the timing of surgery, the perfection of preoperative preparation, and postoperative management are very important.

　　(1)Preoperative preparation:

　　①It is necessary to have a comprehensive understanding of the previous surgical conditions, perform necessary auxiliary examinations, and obtain as complete and clear X-ray bile tract data as possible;

　　②For patients with extrahepatic bile fistula, in addition to keeping the drainage unobstructed and controlling infection, fistulography should be performed;

　　③For patients with jaundice, liver protection therapy should be administered, and coagulation mechanism disorders should be corrected;

　　④Patients with poor general condition should receive nutritional support therapy, correct water and electrolyte imbalance, anemia, and hypoproteinemia;

　　⑤Rational and effective use of antibiotics;

　　⑥Patients with jaundice, especially those with bilirubin levels greater than 171～342μmol/L for 3～4 weeks or with infection and renal dysfunction, should be treated with PTCD for jaundice reduction, followed by surgical treatment 2～3 weeks later;

　　⑦Patients with liver cirrhosis and portal hypertension should first undergo staged bile duct decompression and portosystemic shunt surgery, improve liver function before deciding on definitive surgery;

　　⑧To enhance the body's stress response, patients with poor general condition should be administered dexamethasone 5mg/d intraoperatively and postoperatively.

　　(2)Basic principles of surgery: The surgical procedures should be standardized, and efforts should be made to achieve success in one attempt. It is not an exaggeration to say that the patient's life depends on the needle and thread of the surgeon. Regardless of the type of operation adopted, successful repair must comply with the following principles:

　　①The anastomosis between bile duct and bile duct, or between bile duct and intestinal tract should be achieved with mucosa to mucosa;

　　②The anastomosis should be sufficiently large and tension-free;

　　③The blood supply to the anastomosis is good;

　　④The time for the internal support tube should be long enough;

　　⑤The liver should be routinely drained and kept unobstructed to prevent infection.

　　(3) Selection of surgical method:

　　① Biliary end-to-end anastomosis involves separating and repairing the two ends of the injured and fibrotic bile ducts and then performing an end-to-end anastomosis. Since the sphincter function of the bile duct is preserved, it conforms to physiological requirements, and theoretically, it is the most ideal. In practice, however, the distal bile duct often atrophies and becomes fibrotic, making it impossible to perform an end-to-end anastomosis with the dilated proximal bile duct. Even if resection is performed, it is difficult to complete a tension-free anastomosis, and it is also very easy to destroy the axial blood supply of the bile duct, leading to a high rate of restenosis after surgery. Therefore, it is rarely used for patients with advanced bile duct stenosis and is only suitable for those with annular stenosis.

　　② Biliary duodenal anastomosis involves anastomosing the common bile duct with the first part of the duodenum. Bile flows into the duodenum, which conforms to the normal physiological pathway. There are two types of procedures: side-to-side anastomosis and end-to-side anastomosis. The side-to-side anastomosis is simple to perform, but due to the tension factors at the anastomosis, it tends to narrow progressively, leading to recurrent cholangitis, with the anastomosis becoming smaller and even needle-like. This method is also prone to the reflux of chyme, and the blind end of the bile duct can accumulate stones, often complicated by retrograde infection, and is therefore used as little as possible. The end-to-side anastomosis can reduce these complications, but due to the distance, the anastomosis is often difficult, the operation is complex, and there is a high possibility of leakage after surgery, which often results in duodenal fistula, posing great harm. This surgery is now less commonly used, and side-to-side anastomosis is only used for older patients. To reduce bile-enteric reflux and the sequelae of the blind end, in recent years, some people have designed valvular成形术 at the anastomosis or adopted the choledochojejunal anastomosis after the duodenum, which has shown good short-term effects.

　　③ Roux-en-Y hepatojejunostomy: It involves placing a segment of jejunum between the bile-enteric anastomosis and the enter-enteric anastomosis to prevent the reflux of chyme. Due to the anatomical characteristics of the jejunum such as its softness and length, it can be used not only for extrahepatic bile duct lesions but also for intrahepatic bile duct lesions. Moreover, the size of the anastomosis is not restricted, making it suitable for any difficult biliary-enteric reconstruction. It can achieve tension-free anastomosis, is currently the most commonly used, and has good effects. It is also convenient to perform reoperation when the anastomosis narrows again. The surgical method: Incise and ligate the mesentery of the jejunum 15cm below the Treitz ligament, where the second vascular arch is located, to give the jejunal bridge loop greater mobility. Close the distal end of the bridge loop, elevate it 50 to 60cm from the avascular area of the transverse colon mesentery, and perform an end-to-side or side-to-side anastomosis with the common bile duct (or gallbladder). The anastomosis should be sufficiently large, and if necessary, the distal end of the bile duct should be cut into a bevel or fish mouth shape to enlarge its diameter. Perform a semicircular double-layer anastomosis between the proximal jejunum and the jejunum, and suture the muscularis mucosa of the proximal jejunum and the bridge loop synchronously for 6 to 8cm to prevent reflux. Place a support tube for drainage for 6 months to prevent stenosis. Although Roux-en-Y hepatojejunostomy has effectively solved the problem of restenosis, some patients still experience bile-enteric reflux. To prevent reflux, Wang Xunying designed an artificial jejunojejunal intussusception on the bridge loop, intended to act as a valve. Huang Zhiqiang and others designed an artificial papilla. Both have good short-term effects, and the long-term efficacy is yet to be further evaluated. In addition, after Roux-en-Y hepatojejunostomy, the inflow of bile into the jejunum affects the neutralization of bile by gastric juice, which is prone to duodenal ulcers, with an incidence rate reported abroad of 1.7% to 22%, significantly higher than that of choledochojejunal anastomosis.

　　④ Interspace jejuno-choledochoduodenal anastomosis: This is to place a short jejunal loop between the bile duct and the duodenum. Transfer bile juice into the duodenum to maintain normal acid-base balance in the digestive tract, which is in line with normal physiology. The surgical method is to free the dilated bile duct above the stenosis, suture and close the distal end. Cut a segment of jejunum with mesenteric vascular arch, usually the second or third jejunal vascular arch, the proximal end of the jejunal loop is atresia. The distal end of the jejunum is excised 3-4 cm of serosal layer, leaving the mucosal layer, and the mucosal layer is flipped upwards and sutured to form an artificial papilla. The proximal end of the jejunal loop is elevated through the mesentery above the transverse colon to the porta hepatis and performs a biliary-enteric end-to-side anastomosis. Free the second and third segments of the duodenum, make a transverse incision in the anterior wall of the second segment below, insert the papilla, and suture the bowel. Close the mesenteric space, and pay attention to prevent mesenteric torsion. Since bile juice flows into the duodenum, the acid-base balance in the digestive tract is normal, and the incidence of digestive tract ulcers is significantly reduced. Interspace jejunum can reduce the tension at the anastomosis, and the postoperative stenosis rate decreases. Moreover, adding an artificial papilla at the distal end of the jejunal loop can effectively reduce the reflux of duodenal juice. However, this surgical method is complex and difficult, requiring three anastomoses, and is still difficult to widely promote.

　　⑤ Biliary repair surgery: Using the patient's own tissue or other biological materials to repair the stenosis of the bile duct, the purpose is to preserve the natural channel of bile and the function of the Oddi sphincter. Although the number of cases is not many, all have achieved good efficacy. Materials that can be used include autologous gallbladder, vascularized gastric wall, vascularized jejunum or ileum wall, umbilical vein, great saphenous vein, round ligament of the liver, peritoneum, etc. Wang Yu reported that the use of a calf pericardium to repair bile duct stenosis also achieved good results. However, biliary repair surgery is generally only suitable for incomplete obstruction of bile duct stenosis.

　　(4) High-level biliary-enteric reconstruction may sometimes require the placement of a supporting tube, which is generally retained for more than 6 months. This is to ensure that the fibrosis process matures and solidifies on the stent, which is of great significance in preventing restenosis and improving efficacy. Some authors also believe that if the anastomosis is greater than 1.5 cm, a supporting tube may not be needed. The areas affected by post-injury stenosis mostly involve the high-level proximal bile duct, where the proximal extrahepatic bile duct lacks sufficient length for repair and reconstruction. Recurrent cholangitis leads to fibrosis, atrophy, narrowing of the lumen, and scar formation in the porta hepatis, making it more difficult to anatomically reconstruct the bile duct. If there is bile leakage or obstructive jaundice causing liver function damage and coagulation mechanism disorders, bleeding is often profuse during dissection, making it difficult to obtain a healthy, well-vascularized bile duct of appropriate caliber for anastomosis. Even if anastomosis is勉强 performed, the rate of restenosis is still high. With the increase in the number of operations, scarification also becomes more severe, making reoperation more difficult and the success rate lower. Therefore, to ensure the success of surgical treatment and prevent the recurrence of stenosis, it is necessary to retain the internal supporting drainage tube for a long time. The supporting drainage tube has the following functions:

　　①Support the bile duct to prevent stricture;

　　②Drainage and decompression is conducive to the growth of the anastomosis;

　　③Postoperative irrigation is conducive to the removal of residual stones and retains a passage for endoscopic treatment;

　　④It can provide a passage for postoperative contrast. The retention time of the internal support drainage tube depends on the anatomical and pathological conditions of the extrahepatic bile duct used for repair, the technical difficulty, and the estimation of the time required for fibrosis maturation. Since there are more opportunities for recurrence after the repair surgery of bile duct stricture, the retention time of the support tube should be 6 months to 1 year, and the longer the number of surgical procedures, the longer the retention time should be. The support tube can be divided into Y, T, and U-shaped tubes according to shape. It can be divided into latex tubes, silicone tubes, and so on according to material. Abdominal support is to extract a tube to support the anastomosis from above or below the anastomosis. Hepatic support is to pass the external end of the drainage tube through the hepatic bile duct, then exit the liver substance from the diaphragmatic surface of the liver, and be led out from the abdominal wall, with the other end pulled out in the opposite direction to the extrahepatic bile duct side, and also exit through the abdominal wall and be fixed. The entire drainage tube shape is like a U, which is the U-tube technique, and the proximal end can also be left in the intestinal lumen without being drained. The U-tube technique has the functions of drainage and support, and it is easy to replace after the catheter ages. However, there are also defects, such as causing subdiaphragmatic abscess, biliary tract infection, and bringing many inconveniences to the patient's life. Recently, there is a method of exo-endoprosthesis, that is, to bury the drainage tube under the skin, and leave the other end in the intestinal lumen through the bile-enteric anastomosis. When it is necessary to flush and contrast, the operation can be performed from the end buried under the skin. This surgical procedure has a high quality of life after surgery for the patient, and it is easy for the patient to accept.

　　(5) Factors affecting prognosis: Factors affecting the efficacy in surgical operations include:

　　①The repair technique was improper, and the anastomosis did not achieve mucosa-to-mucosa, with tension at the anastomosis;

　　②The placement position of the support tube was improper, and there was no bile drainage after placement;

　　③The time for removing the drainage tube was too early, and the supporting time was insufficient;

　　④The anastomosis between the bile and intestine is too small;

　　⑤During the reoperation, the bile duct above the obstruction was not found;

　　⑥During surgery, the axial blood supply at 3 and 9 points along the longitudinal axis of the bile duct was not noticed.

　　In addition, the type of stricture can also affect the efficacy:

　　The higher the injured site, the greater the difficulty in repair, and the more opportunities for failure;

　　② The more times of repair and reconstruction, the greater the possibility of postoperative recurrence of stricture.

　　③ Patients with long-term obstruction, accompanied by liver cirrhosis and portal hypertension, have low immunity after surgery, and there is a high chance of complications and recurrence of stricture.

　　(6) Non-surgical treatment:

　　① Dilation of bile duct stricture through T-tube tract: It is suitable for stricture of bile-enteric anastomosis, bile anastomosis, secondary stricture due to surgical injury, and inflammatory stricture at the lower end of the bile duct. In summary, as long as the stricture range is limited and accessible through T-tube tract, this procedure can be performed. After performing T-tube angiography to clarify the condition, place a guide wire into the stricture site along the T-tube under fluoroscopy, and then insert an expander along the guide wire. Starting from F8, use F12, F14, F16 sequentially to reach the stricture section with a diameter of F18. Finally, fix and retain the F18 expander that passes through the stricture section, and connect it to the drainage device. Expansion can also be carried out in stages. Sometimes, a lateral port is opened near the stricture site to facilitate drainage. The final support time should be more than 2 months to reduce recurrence.

　　② Percutaneous liver puncture balloon dilation: It is mainly used for benign strictures of the extrahepatic bile ducts that are relatively short, and it can also be applied to large strictures of the intrahepatic bile ducts, but it has high technical difficulty and low success rate. First, perform PTC, and under fluoroscopy, deliver the balloon catheter to the stricture site through the PTC drainage tube, inject contrast agent into the balloon, further confirm and adjust the position of the balloon catheter. After the position is satisfactory, pressure expansion is performed once a day, and it can take effect in 2 weeks. Before removing the balloon catheter, a stent can be placed to prevent recurrence. In recent years, the memory alloy stent has been carried out with optimistic results, which has very important clinical significance.

　　③ Endoscopic sphincterotomy (EST): It is only suitable for strictures at the distal end of the common bile duct, and the stricture site should be less than 3cm.

　　④ Cholangioscope treatment of biliary stricture: Specialized catheters can be used for expansion and placement in absolute strictures caused by surgery or trauma, and nylon balloon catheters can also be used for expansion treatment.

　　II. Prognosis

　　The mortality rate of biliary tract injury is about 5%, and disabled patients are very common. If the injury cannot be repaired, recurrent cholangitis and secondary liver diseases are inevitable.

　　The success rate of surgical correction for stricture is about 90%. In some medical centers treating stricture, their experience suggests that patients who have undergone multiple treatments without resolving the obstruction can also achieve good results. Therefore, liver transplantation treatment does not need to be considered for such diseases.