Biliary complications after LDLT include bile leak (anastomosis, incision, T-duct outlet), stricture (anastomosis, bile duct), biliary sludge accumulation, common bile duct stones, septic cholangitis, etc. The incidence of complications reported by different centers varies widely. The incidence of recipient bile duct complications in children ranges from 5-34%, with rates of anastomotic leak and stricture ranging from 7-21% and 0-24%, respectively. The incidence of biliary complications in adult LDLT patients ranged from 0-60% (0-37% for anastomotic leak and 0-40% for stricture). The majority of biliary strictures in living liver transplantation are anastomotic strictures, except for multiple intrahepatic biliary strictures due to arterial complications, which are more severe in right lobe donors. 1. Etiology: Living liver transplantation has its uniqueness, including not only the factors of biliary strictures due to its cadaveric liver transplantation, but also those of the liver graft. The causes of biliary complications are multifactorial. Risk factors include age and sex of the recipient, severity of the primary disease, anatomical variation of the bile duct, number and size of reconstructed bile ducts, technique of donor liver harvesting and resection of the diseased liver, bile duct ischemic injury (hepatic artery complications, cold and heat ischemia, bile duct blood supply), mode of bile duct reconstruction (type, suture pattern, suture material, use of stents or T-tubes, etc.), immunological factors (ABO incompatibility, preexisting antibodies ), infection (septic cholangitis, cytomegalovirus infection), etc. Bile leak is one of the most important stricture factors other than technical ones. Its possible cause is the local action of bile, which leads to inflammatory reaction and fibrosis, and bile leak may also be indirect evidence of poor local blood supply, which is a direct cause of biliary stricture.Hwang et al. pointed out that end-to-end anastomosis of fine bile ducts (<4 mm) is one of the risk factors for stricture. This result remains to be confirmed by more other studies. The association between multiple biliary anastomoses and biliary strictures was either not confirmed by studies or was not statistically significant. However, multiple biliary anastomoses are associated with biliary leakage. Recent studies have found that older donors and the presence of postoperative bile leak were independent risk factors in multivariate analyses. The mechanism for the development of biliary strictures in elderly donors is unknown and may be related to age-related degeneration of the biliary microcirculation in elderly donors. 2. Prevention and treatment: Traditionally, the bile-intestinal anastomosis in living liver transplantation is
Roux-en-Y hepatico-intestinal anastomosis, which is applied because of the lack of experience in carrying out early living liver transplantation and is a last resort in order to solve the problem of short biliary tract and anastomotic safety considerations. Its disadvantages are increased surgical trauma, opening of the intestinal canal increasing the chance of infection and intestinal fistula, increased risk of secondary cholangitis due to the loss of the sphincter of Oddi, and difficulty in treatment if postoperative strictures develop. With increased experience with living liver transplantation and improved surgical techniques, more opinion has been expressed on the application of end-to-end anastomosis, as its maintenance of physiological continuity of the biliary intestine has become the standard approach. The prevention of biliary complications after LDLT should be based on two major aspects: anatomical factors and technical factors. Anatomical factors: Precise knowledge of biliary anatomy is essential to ensure donor safety and reduce postoperative complications. According to Couinaud, the confluence of hepatic ducts has been divided into six types: (A) typical (57%), (B) three-branch confluence (12%), (O
ectopic one right hepatic duct (anterior or posterior branch) confluent to the common bile duct (20%), (D) ectopic one right hepatic duct (anterior or posterior branch) confluent to the left hepatic duct (6%), (E) absent hepatic duct confluence (3%), and (F) absent right hepatic duct with ectopic right posterior branch confluent to the cystic duct (2%). Precise knowledge of these special cases is extremely important to reduce the number of bile duct reconstructions and to avoid damage to the bile duct near the donor confluence. The biliary blood supply is divided into 3 segments: hepatic portal, supraduodenal and posterior pancreatic. The superior duodenal bile duct receives 60% of the blood supply from the posterior branch of the pancreatic-superior duodenal artery and from the arteries of the 3 and 9 o’clock axes emanating from the gastric-duodenal artery. The bile ducts receive 2% of the blood supply laterally from the innominate hepatic artery. A thin plexus of these marginal arteries rises to the porta hepatis to join and nourish the common bile duct. The right and left hepatic arteries account for 38% of the blood supply to the biliary arteries; they nourish the confluence and both hepatic ducts through a plexus of portal veins below the hilum. Therefore, the superior duodenal blood supply should be protected during resection of the recipient liver. Damage to the bile duct blood supply may cause ischemic atrophy of the bile duct, leading to anastomotic leakage, stricture, or even bile duct gangrene. Technical factors: Special attention should be paid to the determination of the plane of intrahepatic bile duct division by intraoperative cholangiography. Any injury to the bile duct of the graft by cautery, clamping, or blunt separation should be avoided Any tiny bleeding spot at the opening of the bile duct requires fine stitches and ligation. Care should be taken not to interrupt the arterial blood supply to the biliary tract and to leave a long enough bile duct for a tension-free anastomosis. The connective tissue encircling the hepatic artery and bile duct at the end of the bile duct at the porta hepatis should be left as intact as possible. lee et al. reduced biliary complications during resection of the recipient liver by a new approach to the bile duct through the intrahepatic G1issonian system approach. It made possible a tension-free end-to-end anastomosis and better preservation of the biliary blood supply. The incidence of biliary strictures may be reduced by applying synthetic monofilament absorbable sutures because of their suitability for suturing and low tissue reaction. Intermittent sutures have a high risk of biliary leakage, but continuous sutures have a high rate of stricture. Combine the benefits of both with continuous sutures in the posterior wall and interrupted sutures in the anterior wall. The use of microsurgical techniques in hepatic artery anastomosis has a clear effect on reducing hepatic artery thrombosis, leading to the introduction of biliary reconstruction (<2 mm diameter) with microsurgical techniques, which has recently been reported to reduce the incidence of biliary strictures. In conclusion bile duct reconstruction should follow the principles of tension-free and adequate anastomotic blood flow. Treatment: The cause and management of biliary complications varies depending on the time of day. The vast majority of complications occur within a few days to 3 months as early complications. Sectional biliary leaks can often be successfully controlled by fine needle aspiration and drainage, while endoscopic nasobiliary drainage (ENBD) is usually effective for leaks at the T-duct opening. If the anastomotic leak is not large, endoscopic or percutaneous biliary stenting is sometimes effective. When a large leak or bile duct necrosis occurs, it is necessary to redo the biliary anastomosis, change from an end-to-end bile duct anastomosis to a common hepatic duct-jejunum anastomosis, or redo the liver transplant. For bile duct strictures, the vast majority occurs at the anastomosis. Percutaneous balloon dilation and stenting or transendoscopic stenting with or without dissection of the papillary sphincter is usually effective. The prevention and treatment of biliary complications after liver transplantation has attracted great attention from transplantation experts worldwide. While improving surgical techniques for biliary reconstruction, the risk factors for biliary complications after liver transplantation will be further defined through prospective randomized controlled trials, and biliary complications after liver transplantation will definitely be completely resolved.