The most suitable disease for neuroendoscopic techniques is arachnoid cysts because the cyst cavity is filled with crystal clear cerebrospinal fluid, which provides a spacious operating space for endoscopic techniques. Zhou Yan, Department of Neurosurgery, Air Force General Hospital Arachnoid cysts can gradually increase in size and compress surrounding brain structures or cause obstructive hydrocephalus. The goal of surgery is to communicate between the arachnoid cyst and the ventricles or brain pools, and the simpler the method, the better. The fistula should be large enough to avoid scar formation that could lead to reclosure of the fistula. Neuroendoscopic surgery can be performed as long as the arachnoid cyst produces appropriate symptoms and there are no contraindications to surgery. The surgical treatment of asymptomatic arachnoid cysts is more controversial. My personal opinion is that in adults, asymptomatic arachnoid cysts can be observed clinically and surgery can be suspended; however, in children, arachnoid cysts with significant occupational effects should be recommended to their parents for neuroendoscopic surgery, even if there are no clinical symptoms, because of the impact on the development of the surrounding normal brain tissue. Here, we will start with “suprasellar arachnoid cysts”. Suprasellar arachnoid cysts often lead to obstructive hydrocephalus due to blockage of the interventricular foramen or the middle cerebral aqueduct. Usually, this procedure does not require neuronavigation involvement. The cranial borehole is located roughly 2.5 cm next to the midline and 1 cm anterior to the coronal suture. the endoscope is first introduced into the lateral ventricle. Most of the interventricular foramina are very spacious. The arachnoid cyst apex is stented at approximately 1 x 1 cm, and the edges of the stoma are cauterized with bipolar electrocoagulation. The endoscope is then introduced into the cystic cavity, where we can usually see very clearly the vascular-neural structures of the anterior pontine pool. In almost all cases of suprasellar arachnoid cysts, we find an arachnoid valve in the vicinity of the basilar artery, which is probably the main pathogenetic factor in the formation and progressive enlargement of the arachnoid cyst. If possible, a second fistula needs to be completed between the arachnoid cyst and the basal pool so that a ventricular-arachnoid cyst-basal pool traffic is formed. We will further understand this procedure with you through a typical case. This is a 9-year-old girl with the main clinical symptom of progressively worsening headache that lasted for one year. Brain MRI showed a giant suprasellar arachnoid cyst with bilateral asymmetric dilatation of the lateral ventricles. Because the left lateral ventricle was larger, the surgical approach was chosen to enter from the left side. Because of the arachnoid cyst occlusion, the left interventricular foramen was abnormally dilated. Circumferential electrocoagulation of the wall of the arachnoid cyst was performed. The arachnoid cyst wall is incised and fistulated using a two-handed technique. Wide fistula opening. Entering the cavity of the arachnoid cyst, the basilar artery, the posterior cerebral artery, the superior cerebellar artery, and the arteriolar nerve are immediately visible. The above neurovascular structures were further visualized with a 30° endoscope. A further 45° endoscope is used to visualize and confirm the patency of the midbrain aqueduct. The pituitary gland and pituitary stalk were visible anteriorly. The internal carotid artery, ophthalmic artery, posterior communicating artery, anterior choroidal artery, and superior pituitary artery complex (at the arrow) are then visualized by deflecting the endoscope to the right. A cleft-like living flap on the arachnoid can be found around the basilar artery (at the arrow). The arachnoid is first cut around the basilar artery with microscissors. The incision is then enlarged with Decq forceps. This is the final arachnoid cyst-basal pond fistula. The internal meridian is then introduced into the basal pool, and the abducens nerve, anterior inferior cerebellar artery, and basilar artery are visible. The endoscope is withdrawn from the lateral ventricle, and the final fistula is created as a lateral ventricle-arachnoid-basal pool fistula. A repeat brain MRI 3 months after surgery showed a spacious, unclosed fistula with unobstructed flow of cerebrospinal fluid through the fistula. The arachnoid cyst and hydrocephalus were significantly reduced. The child’s headache symptoms completely disappeared.