The most common symptoms are gastrointestinal bleeding and hypersplenism, which seriously affect the quality of life of children and even threaten their lives. Traditional surgical treatments are not as effective as they could be, and the advent of Rex surgery has brought new hope to many children with portal hypertension. What is pediatric portal hypertension? What are the clinical manifestations? What are the risks? Portal hypertension is a group of syndromes caused by a persistent increase in portal venous pressure. Elevated portal pressure and blood stagnation lead to the formation of a large number of open collateral circulation and varices, which can shunt some of the portal blood to reduce portal hypertension as a compensatory response of the body. The esophagogastric fundus is the closest to the portal vein and therefore the varices are most visible in this area. During gastroscopy we can see the varices bulging like worms on the mucosal surface of the lower esophagus and gastric fundus. The mucosa on the surface of the varices is very weak and when they are scratched by food, stimulated by drugs or corroded by gastric acid to form ulcers, they can easily cause gastrointestinal hemorrhage, which is manifested by vomiting blood or passing black blood stools in children and can endanger their lives if left untreated. In addition, secondary enlargement of the spleen due to spleen stasis leads to hypersplenism, which is characterized by anemia (decreased red blood cells), bleeding tendency (decreased platelets), and decreased body resistance (decreased white blood cells). In addition to these two main symptoms, portal hypertension can cause several other related problems such as impaired liver function, indigestion, hepatic encephalopathy, decreased learning ability, and impaired growth and development. How is portal hypertension classified? Portal hypertension is classified into 3 types according to the site of portal vein obstruction: prehepatic, hepatic and posthepatic. In adults, most of the cases are hepatic, which is caused by cirrhosis; in pediatric patients, prehepatic is the majority, and the literature reports that it can account for 40-50% of the cases. Prehepatic portal hypertension refers to the total or partial obstruction of portal vein due to thrombosis or malformation, followed by compensatory formation of a large number of collateral vascular tufts in the portal region of the liver, showing spongy mass-like changes on CT or ultrasound imaging. This name was adopted by later generations and has been used ever since. The cause of cavernous transformation of the portal vein is still not fully understood; some scholars believe that it is congenital, while others believe that it is secondary to portal vein thrombosis. What are the traditional methods of treatment? What are the results? For the surgical treatment of portal hypertension, the most commonly used methods are still the traditional dissection and bypass. Both surgical methods are aimed at solving the problem of bleeding esophagogastric fundic varices and are palliative procedures to relieve the symptoms, not to achieve a radical cure. Moreover, the surgery cannot solve the problems of portal hypertensive gastric and enteropathy and hepatic encephalopathy, and the incidence of recurrent bleeding after surgery is also high, and the quality of life is greatly affected. Although esophageal variceal sclerotherapy with injection or ligation is an effective conservative treatment, it only provides relief for a period of time after treatment and requires repeated maintenance therapy several times. Why is Rex surgery a curative treatment? In the last 10-20 years, there have been breakthroughs in the treatment of pediatric portal vein cavernous degeneration. de Ville de Goyet first used the Rex procedure in 1992 for the treatment of portal vein thrombosis after liver transplantation and later for portal vein cavernous degeneration. the Rex procedure involves bridging a segment of blood vessel between the superior mesenteric vein and the Rex fossa, the left branch of the portal vein. This allows the blocked portal blood flow to pass through the bypass vessel to the liver, restoring normal circulation to the portal system. In theory, the procedure is a radical treatment for the cause of portal vein cavernous degeneration, and the child can recover completely after the procedure; in practice, the Rex procedure has also achieved satisfactory results. According to foreign literature, after surgery, the hypersplenism of the child is relieved, the varicose veins disappear, the liver function is further improved, the hepatic encephalopathy is relieved, and the growth can catch up to that of a normal child. The success rate of the operation has been reported in different hospitals between 65% and 92%. Due to the complexity and difficulty of the operation, the application of the procedure has been somewhat limited. In China, the procedure has only just started to be used in recent years. (Because the bypass vessel needs to be anastomosed at the Rex fossa of the left branch of the portal vein, the procedure is called Rex surgery, or Rex shunt surgery. Our experience: We have performed more than 20 cases of Rex surgery so far, and according to the results of postoperative follow-up, the success rate of the surgery reached 90%, with no recurrent gastrointestinal bleeding after surgery, remission of hypersplenism, and satisfactory results of routine gastroscopy six months after surgery, which revealed that the varices of the child were significantly reduced or disappeared. What are the indications for the Rex procedure? Due to the good therapeutic results achieved by the Rex procedure, it has also changed the concept of surgery for portal vein cavernous degeneration. While in the past it was thought that surgery was only necessary in cases of gastrointestinal bleeding or severe hypersplenism, the current surgical concept is that prophylactic surgery can be performed in children with portal spongiform degeneration who have only mild hypersplenism. Two of our Rex surgery patients have undergone prophylactic surgery with excellent results. The Rex procedure is designed for patients with portal vein cavernous degeneration and is therefore not suitable for children with cirrhosis. In addition, there are individual children with portal vein cavernous degeneration who cannot undergo the Rex procedure because the portal vein obstruction has reached the Rex fossa. The feasibility of this procedure is determined by intraoperative dissection of the Rex fossa, which cannot be accurately determined by conventional methods, and by alternative procedures such as the Warren procedure in cases of Rex fossa atresia. However, for patients requiring prophylactic surgery, accurate preoperative determination of Rex fossa patency is a prerequisite for performing the procedure, and our use of retrograde portal venography of the hepatic veins is a more reliable method. There are different options for the bypass vessels used for Rex surgery, such as the internal jugular vein, external iliac vein, gastric coronary vein, inferior mesenteric vein, splenic vein, etc. Each has its own advantages and disadvantages, depending on the specific situation of the child, but ensuring the effectiveness of Rex surgery is of utmost importance.