Kasai Procedure

Introduction

If your baby has been diagnosed with biliary atresia, or has already had surgery for it, you are likely trying to understand what comes next. The Kasai procedure is the operation used to treat biliary atresia in infants. It is a serious surgery performed in the first weeks or months of life, and it is the first step in what is often a long medical journey.

This guide explains what the Kasai procedure is, why it is done, how the operation works, what recovery looks like, and what to expect in the months and years afterwards. It also covers the possibility of liver transplant, which becomes part of the discussion for many families either soon after the Kasai or years later. The information here is written for parents, in plain language, and is meant to help you have informed conversations with your child’s surgical and liver teams.

What Is the Kasai Procedure?

The Kasai procedure, also called hepatoportoenterostomy, is an operation that restores the flow of bile out of the liver in babies with biliary atresia. It is named after the Japanese surgeon Morio Kasai, who developed it in the 1950s.

To understand the operation, it helps to know a little about how the liver normally works. The liver makes bile, a greenish-yellow fluid that helps the body digest fats and remove waste products. Bile normally flows out of the liver through small tubes called bile ducts. These ducts join together into a larger duct that drains bile into the small intestine.

The Kasai procedure does not replace the missing bile ducts. Instead, the surgeon removes the damaged ducts and connects a loop of the baby’s own small intestine directly to the surface of the liver, in the area where the ducts used to drain. The hope is that tiny bile channels at the surface of the liver will drain into this loop of intestine, allowing bile to flow out and into the gut. When this works well, jaundice clears and the liver is protected from further injury.

It is important to understand that the Kasai procedure is not a cure for biliary atresia. The liver damage that has already occurred cannot be undone, and the disease process may continue even after a successful operation. The goal of the Kasai is to slow or stop the damage and allow the child to grow with their own liver for as long as possible. For many children, a liver transplant will be needed at some point — sometimes in infancy, sometimes in childhood, sometimes in the teenage years or later.

Why Is the Kasai Procedure Performed?

The Kasai procedure is performed to treat biliary atresia. Biliary atresia is a rare condition affecting newborns, in which the bile ducts outside the liver fail to form properly or become blocked soon after birth. The cause is not fully understood. It is not caused by anything a parent did or did not do during pregnancy. It is not inherited in any straightforward way, and it is not contagious.

Babies with biliary atresia usually appear healthy at birth. Over the first weeks of life, signs appear gradually. These include:

• Jaundice (yellow colouring of the skin and the whites of the eyes) that does not go away after the first two weeks of life
• Pale, clay-coloured or chalky-white stools
• Dark urine, often the colour of tea
• Poor weight gain
• An enlarged liver and sometimes an enlarged spleen

Jaundice is common in newborns and is usually harmless. However, jaundice that lasts beyond two weeks of age, especially when combined with pale stools, is a signal that further testing is needed. Doctors investigate with blood tests, an ultrasound of the abdomen, and sometimes a special scan or a liver biopsy. In some cases, a small operation called an intraoperative cholangiogram is done to look directly at the bile ducts.

Once biliary atresia is confirmed, the Kasai procedure is performed as soon as the baby is medically ready. Timing matters a great deal. Surgical societies and pediatric liver teams strongly emphasise that earlier surgery gives the best chance of success. The procedure has the best outcomes when performed before the baby is around 60 days old. Results are generally less favourable after about 90 days, although the operation is still considered in many older infants depending on the individual situation.

Who Is a Candidate for the Kasai Procedure?

The Kasai procedure is considered for any infant with confirmed biliary atresia. The main factors the surgical and liver teams weigh include:

• Age of the baby. Younger is generally better. Babies under 60 days of age tend to do best.
• Severity of liver damage already present. If the liver shows advanced cirrhosis on imaging or biopsy, the team may discuss whether moving directly to liver transplant is a more appropriate path.
• Overall health of the baby. The baby must be well enough to undergo major surgery and general anaesthesia.
• Other birth differences. A subset of babies with biliary atresia have additional differences in organs such as the heart, spleen, or intestines. These can affect surgical planning and outlook.

In some situations, the team may discuss whether the Kasai procedure is the right step at all. If the baby is older and the liver is already severely scarred, some teams move directly to evaluation for liver transplant rather than performing a Kasai that is unlikely to succeed. This is a clinical judgment made by the treating surgical and liver teams in discussion with the family.

Alternatives

For biliary atresia, the realistic alternatives to the Kasai procedure are limited. Biliary atresia is progressive. Without intervention, babies with biliary atresia develop liver failure, typically within the first one to two years of life. There is no medication that can reopen or replace the missing bile ducts.

The two paths usually considered are:

• Kasai procedure first, with liver transplant later if needed. This is the most common approach worldwide. The Kasai gives the baby the chance to grow with their own liver. Even when transplant becomes necessary later, the time gained allows the baby to grow larger and stronger, which can improve transplant outcomes.
• Primary liver transplant. In selected situations — usually when the baby is older at diagnosis and already has advanced liver damage — the team may discuss moving directly to liver transplant without performing a Kasai. This decision depends on the child’s condition, donor availability, and the assessment of the transplant team.

Medications alone are not an alternative to surgery. Certain medicines are used as supportive treatment alongside surgery — to help bile flow, prevent infection, and support nutrition — but they cannot treat the underlying blockage.

Preparing for the Kasai Procedure

Once biliary atresia is diagnosed, surgery is usually scheduled quickly. Preparation takes place over a few days in hospital and involves several steps.

Confirming the Diagnosis

Before the Kasai, the team makes sure biliary atresia is the correct diagnosis. Other causes of prolonged jaundice in newborns — including certain genetic conditions, infections, and metabolic disorders — can look similar but are treated differently. Tests typically include blood work, abdominal ultrasound, a HIDA scan or similar imaging study, and often a liver biopsy. In many centres, the surgeon also performs an intraoperative cholangiogram at the start of the operation to confirm the diagnosis directly before proceeding with the Kasai.

Pre-Operative Assessments

Before surgery, your baby will have:

• Blood tests, including liver function tests, clotting studies, and a complete blood count
• A check for vitamin K levels and supplementation if needed, because babies with cholestasis (poor bile flow) often have low levels of fat-soluble vitamins and may bleed more easily
• An assessment by the anaesthesia team
• A discussion with the surgical team about the operation, risks, and expected recovery

Feeding and Fasting

Your baby will be asked to fast for a few hours before the operation. The exact timing depends on age and the team’s protocol. The nurses will guide you on when the last feed should be and what fluids, if any, can be given closer to the operation.

Emotional Preparation for Parents

This is a difficult time for any family. You are being asked to consent to major abdominal surgery on a very young baby, often within days or weeks of the diagnosis. Ask the team to explain anything that is unclear. Ask what the team expects, what the warning signs after surgery are, and how long the hospital stay is likely to last. Many families find it helpful to write questions down in advance.

What Happens During the Kasai Procedure

The Kasai procedure is performed under general anaesthesia. Your baby will be fully asleep and will feel no pain during the operation. The surgery typically takes between three and six hours, depending on the anatomy and findings.

Step by Step

1. Incision. The surgeon makes a cut across the upper abdomen, just below the rib cage. Most Kasai procedures are performed as open surgery. Laparoscopic (keyhole) approaches have been studied but are not widely considered standard for the Kasai because outcomes have generally been better with the open approach.
2. Confirming the diagnosis. The surgeon examines the liver and bile ducts. An intraoperative cholangiogram — a special X-ray with dye — may be performed to confirm that the bile ducts are blocked or absent.
3. Removing the damaged ducts. The surgeon removes the scarred remnants of the bile ducts outside the liver, including the gallbladder, up to the point where the ducts enter the liver tissue itself.
4. Preparing the intestinal loop. A loop of the small intestine (jejunum) is divided and prepared. This loop will be used to carry bile away from the liver. The remaining intestine is rejoined so that food can pass normally.
5. Connecting the loop to the liver. The prepared intestinal loop is brought up and stitched directly to the surface of the liver, at the area called the porta hepatis where the bile ducts used to drain. The hope is that microscopic bile channels at this surface will drain bile into the loop.
6. Closing. The surgeon checks for bleeding, places drains if needed, and closes the abdomen in layers.

While you wait, a member of the team will usually update you at intervals. The waiting hours are hard. Bring a phone charger, water, and someone to sit with you if possible.

Recovery and Healing

Recovery from the Kasai procedure happens in phases. The first phase is in hospital. The second phase continues for months at home, with regular clinic visits.

In the Hospital

• A breathing tube for the first hours after surgery, removed once they are stable
• An intravenous line for fluids and medications
• A tube through the nose into the stomach to keep the stomach empty while the gut recovers
• A urinary catheter
• One or more drains near the surgical site
• Pain medication adjusted carefully for newborn use

Feeding restarts gradually once the gut begins to work, usually within a few days. Breast milk is generally preferred when available. Some babies need specialised formulas designed for easier digestion when bile flow is still limited.

Antibiotics are usually given through the vein in the first days and then continued by mouth for an extended period after discharge, to lower the risk of an infection called cholangitis (see below).

At Home

By the time you go home, your baby will be feeding, gaining weight slowly, and the surgical wound will be healing. Recovery at home continues for several months. You can expect:

• Frequent follow-up appointments with the surgical and liver teams, initially weekly or every two weeks
• Regular blood tests to check liver function, clotting, and overall growth
• Ongoing medications, often including antibiotics to prevent cholangitis, ursodeoxycholic acid to help bile flow, and supplements of fat-soluble vitamins (A, D, E, and K)
• Nutritional support, sometimes including high-calorie or specialised feeds, because babies recovering from biliary atresia often have difficulty absorbing fats

Signs the Kasai Is Working

The clearest sign that the operation is working is that jaundice gradually fades over the weeks following surgery. Stools become more yellow or green rather than pale. Blood tests show falling bilirubin levels. Doctors and surgical societies consider clearance of jaundice within about three to six months of surgery a key marker of success.

Even when the Kasai works well, follow-up continues for life. The liver team watches closely for signs of ongoing damage, growth problems, or complications.

Risks and Complications

The Kasai procedure is major surgery in a very young baby. The team will discuss risks specific to your child’s situation. Common and important risks include:

Cholangitis

Cholangitis is an infection of the bile drainage system. It is the most common complication after a Kasai procedure and can happen repeatedly. Signs include fever, jaundice returning or worsening, pale stools, and a baby who is unwell. Cholangitis is treated with antibiotics, usually in hospital. Preventive antibiotics are often given for many months after surgery to lower the risk.

The Kasai Does Not Restore Bile Flow

In some babies, the operation does not succeed in establishing bile drainage. Jaundice does not clear, and liver damage continues. In this situation, the liver team will discuss the next steps, which usually means assessment for liver transplant.

Portal Hypertension

As the liver scars, the pressure in the vein that brings blood to the liver (the portal vein) can rise. This is called portal hypertension. It can lead to an enlarged spleen, low platelet counts, swollen blood vessels in the food pipe (varices) that can bleed, and fluid build-up in the abdomen (ascites). Portal hypertension can develop over months or years even when the Kasai initially appeared successful.

Growth and Nutrition Problems

Children recovering from biliary atresia often have difficulty absorbing fats and fat-soluble vitamins. Even with supplements and specialised feeds, growth can be slower than expected. The liver and dietetics team monitor this closely.

Surgical and Anaesthetic Risks

As with any major operation, there are risks of bleeding, infection of the wound, problems with anaesthesia, blood clots, and reactions to medications. The team takes specific steps to reduce each of these.

Progression to Liver Failure

Even with a successful Kasai, the underlying disease may continue to damage the liver over time. Many children with biliary atresia eventually need a liver transplant, sometimes in childhood and sometimes years later. This is not a failure of the Kasai — it is part of the natural course of biliary atresia for many children.

Life After the Kasai Procedure

Life after the Kasai is a long-term partnership with a pediatric liver team. The goals are to keep your child as well as possible, support good growth and development, watch for complications, and plan for liver transplant if and when it becomes necessary.

Ongoing Medical Care

Children who have had a Kasai procedure need lifelong follow-up with a pediatric hepatologist (liver specialist). Visits usually become less frequent over time but never stop. At each visit, the team checks:

• Growth and weight gain
• Signs of jaundice or other liver-related changes
• Blood tests of liver function, clotting, and vitamin levels
• Spleen size and signs of portal hypertension
• Overall development

Imaging studies such as ultrasound are performed periodically. Older children may need additional tests including endoscopy to look for varices.

Nutrition

Good nutrition is one of the most important parts of long-term care after a Kasai. Children may need:

• High-calorie feeds, sometimes through a feeding tube in early life
• Special formulas that contain easier-to-absorb fats
• Daily supplements of vitamins A, D, E, and K
• Regular dietitian input as the child grows

Vaccinations

Children with chronic liver disease, and especially those who may need a transplant in the future, should be fully vaccinated according to their pediatrician’s schedule. Some live vaccines are given before a possible transplant because they cannot be given safely afterwards.

Day-to-Day Life

Many children who have had a successful Kasai grow up to go to school, play, and lead active lives. Specific guidance about activity, school, and travel comes from your child’s liver team, based on how their liver is doing. Contact sports may be discouraged if the spleen is enlarged, but most other activities are usually possible.

Liver Transplant

For many children, liver transplant becomes part of the long-term plan. Roughly half of children with biliary atresia eventually need a transplant in the first few years of life, and a larger proportion will need one before adulthood, even when the Kasai was initially successful. This is not a sign that something went wrong — it is part of the disease itself.

Transplant assessment usually involves a specialist team that evaluates the child’s liver function, growth, complications, and overall readiness. Pediatric liver transplants in India use both living-donor (a parent or close relative donates part of their liver) and deceased-donor approaches. Outcomes for pediatric liver transplant for biliary atresia have improved substantially over recent decades. Your child’s liver team will explain the process if and when transplant becomes part of the conversation.

Emotional Considerations for Families

A biliary atresia diagnosis and the Kasai procedure can be overwhelming. You may move through shock, fear, hope, and exhaustion in quick succession. The early weeks involve hospital stays, frequent appointments, sleepless nights, and many decisions. Even after recovery, the uncertainty about whether and when a transplant might be needed can feel constant.

Some things many families find helpful:

• Talking openly with the liver team about what to expect, including the possibility of transplant
• Connecting with other families who have been through a Kasai, either through hospital-based parent groups or online communities
• Asking for psychological support — many pediatric liver units have social workers or counsellors
• Sharing care responsibilities between parents and trusted family members so that no single person becomes exhausted
• Keeping a simple file of test results, medications, and clinic letters, which becomes very useful at appointments

Siblings of a child with biliary atresia may also need attention and reassurance, especially when much of the family’s focus is on hospital visits.

Frequently Asked Questions

Is the Kasai procedure a cure for biliary atresia?

No. The Kasai is not a cure. It is an operation that aims to restore bile drainage and slow liver damage. The underlying disease often continues, and many children eventually need a liver transplant. When the Kasai is successful, it can give a child years of life with their own liver, sometimes well into adulthood.

Why does the timing of the surgery matter so much?

Biliary atresia causes ongoing damage to the liver from very early in life. The earlier the bile flow is restored, the less scarring has developed and the better the chance the operation will work. Outcomes are best when the Kasai is performed before about 60 days of age. After 90 days, results are generally less favourable, though the operation may still be considered.

Will my child be able to live a normal life after a successful Kasai?

Many children with a successful Kasai grow, attend school, and lead active lives. They need lifelong follow-up with a liver specialist, take medications, and follow nutritional guidance. Some will eventually need a liver transplant. Day-to-day life can be close to normal for many children, especially in the first years after a good response to surgery.

What if the Kasai does not work?

If bile flow does not improve and jaundice does not clear in the months after the Kasai, the liver team will begin to discuss liver transplant. Transplant outcomes in children with biliary atresia have improved greatly over recent decades. Even when the Kasai is not successful, it is not the end of the road.

Will another Kasai be done if the first one fails?

Repeat Kasai operations are not commonly performed. In most situations, if the first Kasai does not establish bile flow, the next step considered is liver transplant rather than a second operation. A second Kasai is sometimes discussed in very specific situations and is a decision made by the surgical and liver teams.

Is biliary atresia inherited? Will future children be at risk?

Biliary atresia is not inherited in any straightforward way. The risk of it happening in a future child is generally considered very low. If you have specific concerns, a discussion with a genetic counsellor or your pediatrician can help.

Can biliary atresia be detected before birth?

Biliary atresia is generally not diagnosed before birth. In some countries, screening programmes use a stool colour card to help parents and doctors detect biliary atresia in the first weeks of life. Awareness of persistent jaundice and pale stools in newborns is the most important way the condition is picked up.

How long will my baby be in hospital after the Kasai?

Most babies stay in hospital for around one to two weeks after the Kasai, sometimes longer. The exact length depends on how feeding is going, whether there are any complications, and the team’s protocols.

What signs should I watch for after my baby goes home?

Contact the team promptly if your baby has fever, returning or worsening jaundice, pale stools, dark urine, vomiting, a swollen tummy, poor feeding, unusual sleepiness, or signs of bleeding such as blood in stools or vomit. Cholangitis can develop quickly and needs urgent treatment.

Conclusion

The Kasai procedure is the first major step in treating biliary atresia. It is not a cure, but it gives many children the chance to grow with their own liver and to be in the best possible condition if a liver transplant is later needed. Outcomes depend on many factors, including how early the surgery is performed, the extent of liver damage at the time of surgery, and the long-term care the child receives afterwards.

Long-term follow-up with a pediatric liver team is essential. So is good nutrition, careful attention to infections, and emotional support for the whole family. The path after a Kasai procedure is rarely a straight line, but it is one that thousands of children and families travel each year. Your child’s liver and surgical teams are the best source of information about your specific situation, and they will guide you through each stage of the journey.