<qa>  What is the location on the head that the shunt catheter enters the brain on itsThe purpose of the study is to compare the survival time time to first shunt failure of ventriculoperitoneal VP shunts inserted through an anterior entry site with those inserted through a posterior entry site in children. Shunt entry site is the location on the head that the shunt catheter enters the brain on its path to the fluid-filled spaces in the brain, the ventricles. Entry sites can be anterior or posterior. 