Definition and Overview
Hepatoportoenterostomy, or more commonly known as the Kasai procedure, is a type of surgery performed for infants with biliary atresia with the goal to reconstruct the biliary system in order to restore bile flow. The operation was named after Morio Kasai, a Japanese surgeon who developed the procedure in the late 1950s. The original procedure has undergone several modifications since then.
Who Should Undergo and Expected Results
In normal individuals, a substance called bile, which is necessary for the body's digestive processes, is produced in the liver and travels through the bile ducts before draining into the intestines. In patients with biliary atresia, the bile ducts are absent or are damaged by an inflammatory process causing an obstruction. As a result, the bile is unable to drain to the bowels and accumulates in the liver leading to the scarring and damage to the liver tissues.
Biliary atresia is quite rare, occurring in approximately 1 out of every 10,000 infants. Its symptoms include jaundice, or a yellowish color of the skin due to the build-up of bilirubin, a yellowish pigment, in the blood caused by the blockage in the bile ducts. Jaundice that persists after the first two weeks of life should be evaluated comprehensively. Patients with biliary atresia also present with dark colored urine and pale (acholic) stools. Severe cases can also present with liver cirrhosis.
Early surgery in patients with biliary atresia is highly advised to prevent irreversible liver injury. The later the surgery is performed, the poorer the prognosis. Ideally, hepatoportoenterostomy should be carried out within the first 2 to 3 months of life. If done within this timeframe, approximately 80% of patients are able to achieve some extent of drainage of the bile and 33% will develop a normal flow of bile leading to the recovery of the liver and restoration of its function. However, as much as half of the patients who undergo the Kasai procedure eventually require a liver transplant. Liver transplant in biliary atresia is associated with high success rates and longer survival.
How is the Procedure Performed?
The Kasai procedure is a technically demanding operation performed by a pediatric surgeon either through traditional open manner (which involves a large abdominal incision) or laparoscopically (which involves the use of specialised instruments inserted through several small incisions).
In the classic open procedure, an incision is made in the upper right side of the abdomen to examine the extrahepatic (outside the liver) biliary ducts. Once the diagnosis is confirmed intraoperatively, the surgeon proceeds with the dissection of the porta hepatis, a specific area on the surface of the liver where the bile drains. The atretic biliary duct segments are then removed. The jejunum, which is part of the small intestines, is then transected and the distal end is directly attached to the liver. In this manner, small patent bile ducts in the porta hepatis will drain directly into the bowels. This portion of the intestine then functions as the body's new bile duct system. The proximal end of the transected jejunum is then attached to another portion of the small intestines in a technique called Roux-en-Y portoenterostomy.
A drain may be inserted prior to the closure of the abdomen. After the operation, the patient is taken to the recovery room for close monitoring. Immediately after the operation, a tube is inserted through the nose to drain the gastrointestinal tract and feeding is gradually initiated. The patient is discharged once fully feeding and without complications.
Possible Risks and Complications
Hepatoportoenterostomy is a major surgical procedure and there are a number of complications that can possibly arise. The most common is the inadequate drainage of bile. This can be due to a number of factors, such as if the residual bile ducts in the porta hepatis are too small, leading to the development of biliary cirrhosis, a condition that will require a liver transplant to correct.
Cholangitis can be another major complication and is an infection of the biliary tract that can result in diminished bile drainage and damage to the liver. Management of the condition involves the use of broad-spectrum antibiotics. Some experts advocate the use of steroids to minimise inflammation. However, there is still no consensus with regard to this practice. Cholangitis may also lead to portal hypertension, another serious complication that also requires a liver transplant for the patient to survive.
A number of other complications may also occur after the surgery, including:
- Malabsorption – This is a common complication addressed by prescribing the patient with a special formula, as well as vitamins
- Bile leaks - This can be managed conservatively with the use of a drain
- Herniation of the bowel through the mesocolon
- Infection and wound dehiscence
Pain and mild swelling of the surgical site
Behrman et al. Nelson Textbook of Pediatrics. Philadelphia: W.B. Saunders Company, 2000.
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Serrano-Díez-Canedo, J.M. Álamo-Martínez, F.J. Padillo-Ruiz, M.Á. Gómez-Bravo (Nov 2015). "Outcomes of Liver Transplantation During Adulthood After Kasai Portoenterostomy Due to Biliary Atresia". Transplan proc 47 (9)