Surgical resection is the key means to treat tumors, and whether the tumor can be removed cleanly is closely related to the prognosis of tumor patients, and even directly affects the length of survival of patients. Glioma is a type of primary malignant tumor in the brain, and whether surgery can remove glioma cleanly is the concern of every glioma patient and family. Gliomas can be divided into two major categories in terms of growth pattern. One type of glioma is more limited in growth and has certain boundaries, such as hairy cell astrocytoma, pleomorphic yellow astrocytoma, subventricular giant cell astrocytoma, and hairy cell mucinous astrocytoma. It is then possible to remove the glioma more completely along this tumor border during surgery, thus making it possible to remove the glioma cleanly. Of course, it is not absolute, if the tumor grows in important structures or invades important structures, blood vessels, nerves, etc., these gliomas may not be removed during surgery in order to protect these structures or blood vessels or nerves. There is another type of glioma, which is also the majority of glioma, with diffuse growth and unclear boundary, including diffuse astrocytoma, mesenchymal astrocytoma, glioblastoma, etc. The tumor does not have boundary with brain tissue. Because the tumor growth has exceeded the range of enhancement or even edema shown by MRI, and also exceeded the actual range seen under the microscope in surgery, but it is impossible to remove it indefinitely in surgery, and the serious complications or even life threatening caused by unlimited expansion of resection are unacceptable to both doctors and patients, so this part of the tumor cannot really be completely removed cleanly. However, this does not mean that it is impossible to remove the tumor anyway, so it does not matter if a little more or less is removed. If the tumor can be resected to the extent shown on the MRI, or to the extent of the non-functional area, it can be clinically “clean” because the survival time and quality of life of the patients with clinically or imaging clean glioma is significantly better than that of the patients with residual tumor. This is because the survival time and quality of life of patients with clinically or imaging cleared gliomas are significantly better than those with residual tumors. Not only the growth pattern of the glioma itself affects the extent of resection, but also the level of medical care directly determines the extent of glioma resection. Experienced neuro-oncology surgeons are able to judge the tumor boundary and resection scope more accurately during surgery; the application of new medical technologies and tools in surgery, such as neuronavigation and electrophysiological monitoring, can also help doctors judge the scope and functional boundary of the tumor, so as to achieve maximum tumor removal and ensure patient safety.