1.Etiological treatment When the interventricular foramen is simply atretic, the brain tissue between it can be punctured by endoscopy. In addition, neuroendoscopy can be used to examine and correct a failed shunt system. common causes of ineffective shunting in obstructive hydrocephalus include formation of fibrous ventricular end of the catheter Common causes of ineffective shunting in obstructive hydrocephalus include formation of fibrous adhesions at the ventricular end of the catheter, or inhalation of blood clots, brain debris or choroid plexus in the catheter. 2, reduce cerebrospinal fluid formation cerebrospinal fluid overproduction caused by hydrocephalus, can be treated by endoscopic lateral ventricular choroid plexus cautery, choroid plexus cautery are unipolar or bipolar electrocoagulation and laser cautery two. The more developed parts of the choroid plexus and the choroid bulb are usually selected for cautery. To prevent bleeding, only the surface of the choroid plexus is cauterized, and the electrocoagulation probe is constantly moved to prevent adhesions. It has been reported that laser cautery of the choroid plexus is less reactive after surgery, commonly used YAG laser optical fiber, power 7~10W. 3, cerebrospinal fluid shunt shunt includes intracranial shunt and extracranial shunt two. Intracranial shunt refers to the third ventriculostomy. When obstructive hydrocephalus occurs, the absorption mechanism of cerebrospinal fluid is not affected, so endoscopy can be used to penetrate the base of the third ventricle to restore the connection between the ventricular system that produces cerebrospinal fluid and the subarachnoid space that absorbs cerebrospinal fluid, so as to achieve the purpose of treating hydrocephalus. The current indications for endoscopic third ventriculostomy are: (1) stenosis of the middle cerebral aqueduct or other non-traffic hydrocephalus; (2) the third ventricle must be wide enough to reach at least 7 mm; a history of radiation therapy and traffic hydrocephalus is contraindicated. When performing a third ventriculostomy, the fistula is usually selected in the midline of the third ventricular floor, behind the funnel fossa, with an opening of 4 mm to avoid damage to the basilar artery and other important structures. If incision is difficult here, end-plate fistulae may be chosen. Jones reported direct penetration by rigid microscopy; Cohen reported laser penetration of the base of the ventricles; Bauer reported penetration by bipolar electrocoagulation or laser through a rigid microscopy-guided tube under the direct view of a soft microscope, and further enlargement of the opening with a catheter after the opening. When extracranial shunt is performed, a shunt can be placed under direct view of the endoscope, and if necessary, the shunt can be placed into the third ventricle to avoid wrapping and obstruction of the shunt by the lateral ventricular choroid plexus; intraoperatively, the intracerebroventricular separation can be opened to change multifocal hydrocephalus into unifocal hydrocephalus, and then a drain can be placed. Compared with traditional treatment, neuroendoscopic treatment of hydrocephalus has the following advantages: ①Small tissue damage, in line with the principles of microinvasive neurosurgery: only a small hole in the skull or a small bone flap is needed to enter the skull, reducing the damage caused by craniotomy; intraoperative endoscopy can be combined with ultrasound guidance technology, stereotactic technology, etc., so that the lesion can be accurately located, rational design of the access, reduce brain tissue pulling, and reduce the damage. ②Observation of operative field and lesion under direct vision, avoiding blindness of intraoperative operation: intraoperative lesion can be directly observed to determine the scope, size and shape of lesion, determine the nature of lesion and carry out reasonable treatment. ③Simplify the surgical operation and shorten the operation time: compared with traditional surgery, endoscopic surgery can greatly shorten the operation time, and the patient recovers quickly after surgery and the hospital stay is reduced.