In the early days, there was no real neuroendoscopy, and endoscopes from other clinical disciplines were mostly borrowed for operation, and they were only used to try to treat hydrocephalus, but due to the coarse diameter of the endoscopes used at that time, poor optical quality and illumination, and the lack of corresponding surgical instruments, the surgery was traumatic, ineffective, and had high mortality rate Endoscopic technology as a diagnostic and therapeutic tool has been widely used in many disciplines, and its minimally invasive As a diagnostic and therapeutic tool, endoscopic technology has been widely used in many disciplines, and its minimally invasive characteristics are accepted by physicians and patients. Neurosurgery is the last surgical field to adopt endoscopic techniques due to the relatively small space available for operation in the brain, but there has been a rapid development in recent years. Neuroendoscopy (neuroendoscopy), also known as ventriculoscopy, can directly or assist neurosurgery, with the advantages of reducing the scope of craniotomy, magnifying the image of anatomical structures in the surgical field, enhancing local illumination, and improving surgical results. 1, the development of neuroendoscopy In the early days, there was no real neuroendoscopy, mostly borrowing endoscopes from other clinical disciplines for operation, and only used to try to treat hydrocephalus, but due to the coarse diameter of the endoscope used at that time, poor optical quality and illumination, and the lack of corresponding surgical instruments, therefore, the operation was traumatic, with poor efficacy and high mortality. In the 1970s, with the advent of the kins columnar lens system, neuroendoscopy entered a new era, and the surgical results of ventricular choroid plexus cautery for hydrocephalus using this endoscopic technique were reported to be significantly better than before, and began to be extended to other neurosurgical procedures. apuzz et al. used endoscopy to assist in the observation of intra-saddle lesions that were difficult to see directly during surgery, as well as Wilis ring The use of endoscopy to visualize intra-saddle lesions that are difficult to visualize during surgery, as well as Wilis ring aneurysms and degenerated lumbar discs, yielded good results. In the 1980s, due to the advent of CT and MR, neurosurgery itself entered a phase of rapid development, transitioning from traditional neurosurgery to micro-neurosurgery and later to minimally invasive neurosurgery. Driven by relevant scientific progress, the speed of updating endoscopy and its supporting instruments has accelerated significantly, and gradually developed in the direction of small size, high resolution and stereoscopic magnification, through which complex operations such as illumination, flushing, suction, hemostasis, cutting, balloon dilation, photography and video can be performed, making endoscopy easier to operate; at the same time, the combination of endoscopy with stereotactic, intraoperative ultrasound guidance, ultrasound suction and laser technologies has initially solved The combination of endoscopy with stereotactic, intraoperative ultrasound guidance, ultrasound suction and laser technologies has initially solved the disadvantages of difficult positioning and poor hemostasis in the use of endoscopy, making the scope of endoscopic treatment increasingly broad. In addition to the treatment of hydrocephalus, it is also commonly used for aneurysm surgery, pontocerebellar angle surgery, observation of saddle area surgery, and treatment of transsphenoidal pituitary adenoma, epidermoid cyst and craniopharyngioma. Austrian neurosurgeon Auer made an outstanding achievement by applying a 6-mm diameter endoscope to treat intracranial hematomas, drilling only 1Cm-sized bone holes in the skull, applying the endoscope for aspiration of the hematoma, localizing the hematoma intraoperatively with the aid of ultrasound, and using a laser for endoscopic hemostasis. He also used the above techniques for brain tumor biopsy, cyst wall resection of intracerebral cystic lesions and laser irradiation of solid tumors, all with good surgical results. 13 endoscopic surgeries were completed, with only 1.6% of surgical complications and no surgical deaths. In recent years, some scholars also used ultrasound, stereotactic and laser technologies for endoscopic surgery at the same time, called ultrasound stereotactic endoscopy (uhrasound stereo taxic endoscopy). German neurosurgeons such as Bauer further applied this technique to the treatment of hydrocephalus, interstitial or intracerebroventricular cysts, brain abscess, intracerebral hematoma, spinal cord cavitation and other diseases, as well as the interstitial radiation treatment of low-grade glioma, and the surgery has achieved good results. The surgical mortality rate was less than 1% and the surgical disability rate was less than 3%. In this period, some scholars put forward the concept of “endoscopic neurosurgery”, emphasizing the important role of endoscopy in microscopic neurosurgery, and divided neuroendoscopic operations into four application methods ① Endoscopic neurosurgery (EN) means that all surgical operations are done completely through the endoscope. Endoscopic neurosurgery (EN) means that all surgical operations are performed entirely through endoscopy, and requires the use of specialized endoscopic instruments to perform surgical operations through the endoscopic canal. It is commonly used for hydrocephalus, intracranial cystic lesions and lesions of the ventricular system, such as rash at the base of the three ventricles, and can be used in cases of failed ventriculoperitoneal shunts. For symptomatic developmental abnormalities of the ventricular system (such as lateral fissure arachnoid cysts, intracerebral parenchymal cysts and lucent septal cysts), the originally closed cysts can be opened to the adjacent ventricles. For intracerebroventricular tumors, biopsy can be taken under endoscopy, and small narrow-tipped tumors (choroid plexus papilloma, fluid cyst) can also be completely resected. Endoscope-assisted microneurosurgery (EAM) is the use of endoscopy to perform operations in microneurosurgery in areas that are difficult to find intraoperatively. The observation of the area outside the microscopic field not only increases the exposure of the surgical field and avoids missing lesions, but also reduces the strain on the brain tissue, decreases postoperative complications and alleviates postoperative reactions. It is used for aneurysm clamping, trigeminal nerve decompression, and cholesteatoma resection in the pontocerebellar horn region. Endoscope-controlled microneurosurgectomy (ECM) is a microneurosurgical procedure performed with conventional microsurgical instruments under the guidance of endoscopic images and with the light source and surveillance system of the endoscope. It differs from EAM in that the main operations are performed endoscopically. The difference with EN is that EN is performed inside the endoscopic tube, while ECM is performed outside the endoscope. The typical ECM is neuroendoscopic resection of pituitary adenoma through a single nostril, which has now become a routine procedure. ④ EndoscopiCinspection (El) refers to the use of endoscopy as an aid to observation during neurosurgical operations, without he operation. Currently, it is mainly used for the observation of intracranial aneurysmal structures, pontocerebellar horn region or other skull base tumors. Perneczky also proposed the concept of keyhole apProach, which makes the surgery more minimally invasive and safe. 2. Application of neuroendoscopy The scope of application of neuroendoscopy has three advantages compared with the operating microscope: ① the endoscopic canal itself can have a lateral view, which can eliminate the intraoperative visual field dead angle, making the operation more delicate and better; ② when reaching the lesion, a panoramic view can be obtained, and the lesion can be “close-up” and magnified. (3) The angled endoscope can reveal some corners of the pontocerebellar horn and basal pool that cannot be reached by the operating microscope. By operating under the direct view of neuroendoscope, bleeding caused by blind puncture can be avoided. At present, there are 2 main applications of neuroendoscopy in neurosurgery: firstly, third ventricle fundoplication, arachnoid cyst, intracerebroventricular micro lesions, resection of cystic lesions in brain parenchyma and other neuroendoscopic operations under direct vision; secondly, it assists in the operation of micro neurosurgery, combining neuroendoscopy and microsurgery flexibly, expanding the scope of exposure and greatly expanding the scope of adaptation of neuroendoscopy. 2.1 Auxiliary intracranial aneurysm clamping In the 1990s, neuroendoscopy was widely used for aneurysm clamping surgery. At present, neuroendoscopy is mainly used for aneurysm surgery in the EAM approach, i.e., the use of neuroendoscopic techniques to assist in observing the structure of the aneurysm, the relationship between the aneurysm and the surrounding vascular nerves, as well as observing whether the aneurysm clamping is appropriately positioned and whether there is misclamping or incomplete clamping after clamping the aneurysm. Because endoscopy requires a clear field and appropriate operating space; therefore, neuroendoscopy is most suitable for surgery of unruptured aneurysms or aneurysms that have ruptured but the subarachnoid hemorrhage has been absorbed, especially for deep aneurysms, which can not only help the operator clearly understand the structure of the aneurysm, but also explore the specific location of the aneurysm tip and the hidden penetrating branch vessels under the posterior wall of the aneurysm, thus reducing the risk of damage to the surrounding brain tissue and important nerves. This reduces the damage to the surrounding brain tissue, important nerves and blood vessels, reduces the incidence of postoperative complications, and helps patients recover sooner. Clamping of aneurysms with ECM means that after exposing the aneurysm and its surrounding structures under microsurgery, endoscopic observation of the specific aneurysm is used, and then clamping of the aneurysm is performed under endoscopy. The advantage of performing aneurysm surgery by ECM is that it avoids overly frequent endoscopy-microscope exchange, and the best viewpoint for clamping the aneurysm is selected according to what is seen by the endoscope, reducing the chance of mistaken clamping or incomplete clamping. The main difference between ECM and EAM is that the endoscope plays a greater role in the ECM approach, but the disadvantage is that the endoscope occupies a certain amount of surgical space, which sometimes prevents further surgical operations and requires higher requirements for the operator, who not only has excellent microvascular surgery skills and rich clinical experience, but also has to be proficient in endoscopic operations, as well as familiar with endoscopic anatomy and endoscopic magnification and distortion. images. 2.2 Single-nostril resection of pituitary adenoma In the past decade, single-nostril neuroendoscopic resection of various pituitary adenomas has the advantages of minimally invasive, less complications, shorter operation time and complete tumor removal. Compared with the transoral nasal butterfly approach, it avoids damage to the nasal structures such as lip-eye incision, nasal septum free and large area of nasal septum stripping, and reduces complications such as atrophic rhinitis, lip-eye sensory loss and tooth-eye atrophy. Operating in the narrow cavity orifice, the endoscope has obvious advantages over the microscope in imaging. The multi-angle endoscope can observe the lateral situation of the deep operative field, which is convenient to grasp the tumor removal, and basically can remove the tumor inside the envelope, which can reduce the damage to the pituitary gland and the surrounding important structures; in addition, the hemostasis is reliable under direct vision, which reduces the complications of postoperative bleeding. Removal of tiny intracerebroventricular lesions Using the surveillance system of endoscopy can assist microscopic neurosurgery in removing tiny intracerebroventricular lesions, such as ventricular and ventricular pool lesions, intracranial cystic lesions, ventricular hemorrhage, brain abscesses, etc. Neuroendoscopy not only allows a clear view of intracerebroventricular morphology and structures, but also allows the operator to clarify the location of intracerebroventricular lesions, the number of multiple lesions, and avoid blind operations. In the process of resection of deep brain lesions, it can observe and remove residual tumors in the blind and shadow areas of microsurgery, which is an important guidance for surgery.