Clinical application of neurosurgical endoscopy In the past 10 years or so, the development of optical fiber technology and computer imaging technology, neuroendoscopy technology has made rapid progress, and with a variety of new neurosurgical techniques and tools, including neuronavigation technology, stereotactic technology, ultrasound, lasers and so on are increasingly integrated, and the scope of its application is constantly expanding, basically covering the various fields of neurosurgery, neuroendoscopy has become a powerful tool for many neurosurgeons. A powerful tool for many neurosurgeons. At present, more than 200 medical institutions in China have purchased neuroendoscopic equipment, accumulated thousands of cases of neuroendoscopic surgical experience, a number of neuroendoscopic training bases, began to gradually standardize the training of some neurosurgeons; the theory of neuroendoscopic technology and clinical application of the research, but also made encouraging progress, micro-invasive endoscopic neurosurgery has become a large-scale in China. 1, ventriculo-parenchymal endoscopy ventriculo-parenchymal endoscopy is the classic application of neuroendoscopy, endoscopic third ventriculostomy (ETV) is becoming mature. With the accumulation of cases and long-term observation of surgical effects, a more comprehensive understanding of the indications and efficacy of ETV for hydrocephalus has been achieved. Obstructive hydrocephalus is the preferred indication for ETV, and the success rate of treatment is as high as 80.7%. Whether traffic hydrocephalus can be treated with ETV has been one of the hotspots of debate. Some foreign studies have reported that the cause of traffic hydrocephalus is due to reduced ventricular compliance, and increased cerebral pulsatile pressure dilates the ventricles.After ETV, cerebrospinal fluid in the ventricles is discharged through the fistula, which can make the excessive systolic pressure in the brain decrease. In clinical application, the postoperative symptom improvement rate reaches 66.5%, which is the same as that of shunt surgery (66%), in which the improvement rate of gait instability is as high as 75%. The application of special fistula techniques, including transparent septum penetration, interventricular foramenoplasty, conduit dilatation, lateral ventricle-tetralogy of Fallot pool penetration, has also been applied to the treatment of complex hydrocephalus and special parts of arachnoid cysts, and good clinical results have been achieved. 2.Skull base endoscopy The special structure of the skull base makes the microscope observation often have a dead angle, and the endoscopy can be angular observation characteristics, so that it can be a good exposure from the base of the anterior cranial recess to the craniocervical junction of the majority of the structure. Since 1992, when Jankowski et al. performed the first endoscopic resection of pituitary adenoma by transnasal butterfly approach, neuroendoscopic techniques have been widely used in the surgical treatment of skull base lesions. With the improvement of instruments and equipment as well as the improvement of people’s understanding of skull base diseases, the scope of its treatment of skull base diseases has been gradually expanded, and the indications have become wider and wider. At present, the application of neuroendoscopic transnasal butterfly treatment of pituitary tumors is less traumatic, better revealed, and more thoroughly resected tumors. The author’s experience with more than one thousand cases of endoscopic transnasal butterfly treatment of pituitary tumor proves that this method has obvious advantages compared with the traditional method. The endoscopic transnasal and transoral approach to the midline region of the skull base has also developed significantly in recent years. Using an endoscopic extended transnasal approach, a wide area of the midline of the skull base from the cockscomb to the foramen magnum of the occipital bone can be visualized. Among them, the surgery via the pterygoid sinus to the slope and the area of the occipital foramen magnum is the surgical manway with the longest path and the deepest operative field among all the transnasal approaches, with the difficulty of instrumentation, the number of important surrounding neurovascular structures, and the complexity of anatomical relationships. Cerebrospinal fluid leakage is the most common and problematic complication in the extended transnasal approach. Its incidence has been reported in the literature to be 0.5% to 15%. Large and irregular cranial defects and dural ruptures put forward higher requirements for skull base reconstruction techniques. In addition to the traditional fat and muscle tamponade techniques, there are foreign reports on the application of tipped nasal septum mucosa and temporalis muscle flap for dural repair of the skull base. However, there is no major breakthrough in new repair materials and techniques. Artificial dura mater and auriculocephalic gel multiple composite are mainly used for skull base reconstruction; for those with obvious signs of leakage, the tumor cavity is first filled with fat, and then reinforced with muscle cushion. The results of these methods are clear, and the incidence of cerebrospinal fluid leakage has been significantly reduced. Endoscopy with microscopic neurosurgical techniques can also play a good role. As the neurosurgeon’s main observation equipment, the combination of microscope and neuroendoscope is the direction of development of skull base surgery. The application of endoscopic cooperation, can make the conventional microsurgery dead space reduction, resection of more residual lesions, protection of normal tissue structure. The value of the application is different in different parts and lesions. For example, when removing skull base tumors, the use of endoscopy can detect and remove residual tumors in the dead space of microscopic observation; in microvascular decompression surgery, it can further determine whether the nerve decompression is complete or not, and even separate the blood vessels and nerves under the endoscopy; in aneurysm surgery, it can be directly visualized to observe the structure of the back of the aneurysm, and confirm the neck of the aneurysm from a different angle, and so on. In addition, endoscopic transnasal and transoral resection of craniopharyngioma, meningioma, and repair of cerebrospinal fluid leakage have also been reported. 3.Spinal endoscopy Neuroendoscopy was applied to spinal surgery at the end of 1980s. With the continuous improvement of endoscopic instruments and the development of imaging and localization technology, including various tubular retractors, the application of YESS (yeung endoscopic spine system), intraoperative navigation, and stereotactic technology, it has been more and more widely used in spinal surgery. Percutaneous endoscopic discectomy and foraminoplasty have become more mature, and endoscopic resection of internal and external spinal tumors, internal fixation of the spine, drainage of paravertebral abscesses, and thoracic sympathetic ganglionectomy have also been increasingly reported. However, there are still some shortcomings in the application of endoscopy in spinal surgery: all instruments are passed from the elongated lumen, which is difficult to operate; the surgical path lacks clear anatomical markers, which often needs to be combined with intraoperative navigation techniques; intraoperative hemorrhage is difficult to control; and the damage of internal organs in the application of thoracoscopy and laparoscopy. These shortcomings make the application of spinal endoscopy is limited, compared with traditional open surgery, its efficacy is not substantially improved. 4, there are problems The current clinical application of endoscopy problems (shortcomings): First, only two-dimensional images can be obtained, the image can have a certain degree of deformation when observed in close proximity. For deeper and more complex lesions, intraoperative localization relies on the operator’s experience or the help of intraoperative navigation. However, the development of new imaging technology is about to break through this barrier. A depth sensor will be added to the end of the new endoscope, and the perceived optical signals can be integrated through the computer system to obtain images with a depth of field similar to that of a microscope. Second, the operator often need to operate one-handed surgical operations, the new artificial intelligence devices will change this situation, these devices have begun to emerge in the field of laparoscopy, cystoscopy, not only to replace the original clumsy endoscopic fixed instruments, so that the operator from the comfort of two-handed operation, and can even carry out some simple surgical operations. The development of endoscopy-specific surgical instruments, such as ultrasonic suction that can be introduced through the endoscopic channel and the application of laser systems, has also greatly expanded the scope of endoscopic applications. Neuroendoscopic technology is maturing, and with the improvement of modern equipment and the accumulation of experience, endoscopy will certainly play an increasingly important role in the field of neurosurgery.