Hydrocephalus surgery usually does not require a craniotomy, because the cause of hydrocephalus is mainly due to excessive accumulation of cerebrospinal fluid in the ventricular system, which is mainly due to excessive secretion of cerebrospinal fluid or obstruction of cerebrospinal fluid circulation in the ventricular system. For the treatment of hydrocephalus, if surgery is required, the preferred procedure is usually ventriculoperitoneal shunt surgery. The ventriculoperitoneal shunt is performed by first cutting the scalp at a fixed location in the back of the head, then drilling a hole in the skull with a diameter of about 1 cm, then cutting the dura mater and placing a drainage tube, after which the other end of the drainage tube is passed through a subcutaneous tunnel directly into the abdominal cavity, so no craniotomy is required for hydrocephalus surgery.