Although shunts are indicated for the vast majority of hydrocephalus, the biggest problem with this procedure is that there is a relatively high percentage of complications. The chance of complications is about more than 20%, and in children under 2 years of age with hydrocephalus V-P shunts is more than 30%, with some large cases reported even more than 50%, significantly higher than in adults, and with dozens of different types of complications. A book could be written on the complications of ventriculoperitoneal shunts alone. 1. Overview of shunt complications Because shunt surgery is a foreign object implanted in the child (even if the rejection reaction is minimal) that significantly alters the original cerebrospinal fluid circulation and basically leaves the shunt in place for life, whether or not this tube will fit and match the child’s current state and long-term future after the surgeon places it in the child – -much of this is beyond the doctor’s complete control. So, there is a greater chance of various problems, or complications, with the shunt. About 90 percent of complications occur in 10 percent of children, meaning that once a complication occurs, the probability of subsequent recurring complications is higher. Serious complications are about 1-4% and include: infection, bleeding, perforation of the gastrointestinal or urinary tract, ascites, peritonitis, pneumothorax, epilepsy, lacunar ventricular syndrome, and isolated ventricles. Relatively minor complications 4-50% include: subdural effusion, pneumocranial, shunt obstruction, shunt dissection, abdominal encapsulation, peritoneal effusion, and mild infection. Frequent complications in infants include: organ perforation, subdural effusion/hemorrhage, subcutaneous effusion, shunt indicating skin ulceration (ulceration), shunt obstruction, displacement, prolapse, abnormal cranial thickening, intra-abdominal pseudocysts, etc. 2, serious – shunt infection The most serious complication of all shunt-related complications is shunt infection, known as the “most expensive infection”, with an incidence of 1-7%. Risk factors for infection include prematurity, low birth weight, history of previous surgery (head and abdomen), inadequate immune response, post-hemorrhagic hydrocephalus, post-infectious hydrocephalus, and spinal cord spondylolisthesis with hydrocephalus. 60-70% of infections occur within the first month after surgery. Once infection occurs, most cases require complete removal of shunts, temporary placement of external drains to control the infection, and seeking the time for re-operation, thus often requiring long hospital stays, multiple surgeries, and huge medical expenses to solve the problem. Another common complication of V-P shunt surgery in children is the problems caused by excessive shunts. The problems associated with overshunting are much greater than those associated with undershunting, so great care should be taken to avoid overshunting in children with hydrocephalus. Excessive shunts can lead to subdural effusion in the short term, and severe effusion often requires external drainage or even the placement of another subdural-abdominal shunt. In younger children, excessive shunts can cause a more severe lacunar ventricular syndrome in the distant future. The fissure ventricular syndrome refers to the extreme shrinkage of the ventricles after prolonged excessive drainage and causes decreased compliance of the ventricular wall, which leads to compression of the ventricular end of the shunt by a very small ventricle, causing intermittent nonperfusion of the shunt, which can cause acute cranial hypertension and significant headache and vomiting. Clinically, the management of lacunar ventricular syndrome is tricky. Therefore, to avoid excessive shunting, the initial pressure of the shunt is often set relatively high, while an adjustable shunt is used to gradually adjust the pressure downward until it reaches a matching, appropriate pressure for the child. Images of a child with lacunar ventricular syndrome, preoperatively, 5 months postoperatively, 10 months postoperatively, and 1 year postoperatively 4. The most difficult problem to determine – shunt obstruction Shunt obstruction is the most common complication and can occur throughout the post-shunt period. Obstruction at the ventricular end is often due to poorly positioned tube heads due to the development of the child’s brain tissue, or inaccessibility due to encapsulation by the choroid plexus, etc. Obstruction in the area of the shunt pump may be caused by prolonged blockage of the delicate shunt pump structures by impurities within the cerebrospinal fluid. At the ventral end, there may be an encapsulated fluid collection in the abdominal cavity or an obstruction by the greater omentum or inflammation in the abdominal cavity. After shunt obstruction, it is often necessary to surgically explore and replace the site of shunt obstruction or even replace the shunt completely with a new one. However, even another replacement does not completely prevent the recurrence of obstruction.