1.What is ventriculo-peritoneal shunt? Ventriculo-peritoneal shunt (V-P shunt) was invented in 1949 with the invention of the shunt pump, and although it is an ancient procedure, it is still an important method in the treatment of hydrocephalus. It is based on the principle of diverting excess cerebrospinal fluid from the ventricles to the peritoneal cavity via an artificial silicone tube, where it is absorbed using the powerful absorptive capacity of the peritoneum. At present, the abdominal cavity is seen to be the best site for extracerebral absorption of cerebrospinal fluid, and organs such as the thoracic cavity and the bladder have been abandoned for various reasons. In special cases when it cannot be placed in the abdominal cavity (e.g., the abdominal cavity has undergone surgery causing adhesions, encapsulation, infection, etc.), the tube can be placed in the superior vena cava or atrium, called a ventricle-atriumshunt (V-A shunt). In adolescent children, if the cerebrospinal fluid of the ventricle and lumbar pool are connected, the shunt tube can also be placed at one end in the lumbar pool and the other end in the abdominal cavity, which is called a lumbar-abdominal shunt (Lumbar-abdominalshunt, abbreviated as L-P shunt). 2, the magic weapon of ventricular-abdominal shunt – shunt tube Since the invention of shunt pump in 1949, there are more than 200 different types of shunt tubes. The market price also ranges from several hundred RMB to tens of thousands of RMB. At present, the main domestic brands include the German company Braun (Braun) under the Snake (Aesculap), the United States (Integra, formerly known as the United States Johnson & Johnson Codman), the United States Medtronic (Medtronic) and France’s Sophysa (Sophysa) shunts. The shunts produced by different companies have detailed differences, but they are generally the same. The following is an example of a German Snake shunt, which describes the construction of a shunt. The shunt includes a ventricular end, a reservoir capsule, a shunt pump, a one-way valve, and a ventral end. The figure below shows the structure of the shunt tube in vitro. Frontal view of the shunt (image from the internet) Ventricular end: placed into the ventricle, usually the lateral ventricle, with a rounded head and many small lateral holes. It is placed into the lateral ventricle through cranial drilling and ventricular puncture. The reservoir sac, which can be felt on the surface of the body, is used to help determine if the shunt is patent. If it does not pop up quickly after being pressed, it indicates that the shunt is not working. It can also be used to extract cerebrospinal fluid through skin puncture of the fluid reservoir for related laboratory tests. Shunt pump: The pressure of the shunt tube is controlled. Currently, most domestic shunt pumps are adjustable, and the pressure of the pump can be adjusted in a non-invasive manner outside the body to control the amount of shunt flow. The pressure generally varies from 40 mmH2O to 200 mmH2O. The magnetic field has an effect on the pump pressure setting of most shunts. Currently, only a few shunt pumps can withstand the magnetic field of 3.0T MRI without being affected, such as Snake’s shunts and Sofisa’s Polaris shunts, while other domestic brands of shunts currently need to be rechecked and the pressure of the shunt pump adjusted after the MRI is done. Unidirectional valve: It is used to control the unidirectional flow of cerebrospinal fluid from the ventricle to the abdominal cavity to avoid reflux. It also has an anti-siphoning effect to avoid excessive drainage. This device is often incorporated into the shunt pump at the time of design. Ventral end: The ventral end is longer, usually through the postauricular, cervical, thoracic, and abdominal regions via the establishment of a subcutaneous tunnel to the abdomen, and can be placed into the abdominal cavity through a small incision or puncture. After learning about the structure of a shunt, parents will want to know how the shunt is placed in their child. The diagram below shows the general location of the shunt and the location of the child’s skin incision. The location and course of the shunt inside the child’s body is shown In the head, the puncture point is usually located at the top of the forehead on one side (i.e., anteriorly), and a shunt can be punctured into the ventricles of the brain by simply opening a curved incision about 2 cm long in the skin and drilling a hole through the skull. The posterior reservoir, regulator, and associated tubing are buried under the skin behind the ear, so that the protruding reservoir and regulator are usually palpable above the child’s ear. The line below the regulator is placed in a “subcutaneous tunnel” that reaches the umbilicus. In children with less subcutaneous fat, a slightly elevated line can be felt under the skin. An incision of approximately 2 cm is also made in the skin next to the navel, and the abdominal end of the shunt is placed into the abdominal cavity through this small incision. This incision is usually difficult to detect after healing because of its location next to the folded belly button. Through intestinal peristalsis, the shunt can usually find a “harmonious” place in the abdominal cavity with the intestine, but this position is, of course, constantly changing. Shunts of 20-40 cm in length are usually kept in the abdominal cavity to accommodate the child’s need for a shunt as he/she grows taller.