Tumors involving the brainstem involve the brainstem, cranial nerves, vertebral basilar and basilar arteries, ventricular pathways, and important structures or functional areas of the brain such as the saddle area, pineal area, rocky-slope area, greater occipital foramen area, pontocerebellar angle area, jugular foramen area, etc. They are related to the patient’s life, neurological, endocrine regulation and conduction and other important neurological functions, and any surgical damage may cause significant neurological dysfunction. Any surgical injury may cause significant neurological dysfunction. Therefore, it is difficult to remove the tumor and avoid damaging the brain stem, cranial nerves, important blood vessels and other important brain structures, which requires good neuroanatomical foundation, advanced microsurgery and neurological monitoring equipment, especially solid microsurgery skills and rich surgical experience. The anterior and superior brainstem mainly involves the third ventricle, hypothalamus, pituitary gland, fundic artery ring and other important tissue structures, and common tumor types include pituitary tumor, craniopharyngioma, meningioma, glioma and so on. 2.The posterior part of brainstem mainly involves pineal region, cerebellar curtain, large cerebral vein and other tissues, and common tumor types include germ cell tumor, meningioma, glioma, etc. These tumors are usually easy to compress the middle cerebral aqueduct and cause hydrocephalus and difficulty in upward vision. 3.The anterior part of brainstem mainly involves tissues and structures such as rock bones-slope, basilar artery, cranial nerve, etc. Common types of tumors include meningioma, chordoma, cholesteatoma, nerve sheath tumor, etc. The preoperative symptoms are milder and the course of disease is longer, but the tumor location is deeper and more difficult to operate. 4.Lateral side of brainstem mainly involves pontocerebellar horn area, jugular foramen area and other tissue structures. The posterior part of brainstem mainly involves the fourth ventricle, cerebellar earth, cerebellar peduncle and other tissues. The common types of tumors include medulloblastoma, ventricular meningioma, astrocytoma, glioma and vascular reticulocytoma. 6.Below the brainstem, it mainly involves the occipital foramen, vertebral artery and other tissues. The common types of tumors include meningioma, nerve sheath tumor, glioma, etc. These tumors may easily cause dyspnea, hydrocephalus and cranial hypertension. 7. Brain stem tumors, common types include astrocytoma and other glioma and vascular reticulocytoma, with different clinical manifestations and treatment methods. Selecting and designing a good surgical approach is the key step to successful surgery. The general principle of designing the surgical approach is to facilitate the exposure and resection of the lesion while avoiding and protecting the important structures of the brain to the greatest extent possible. We usually select and design our surgical approach based on the classical approaches in the past, combined with the neurological navigation and the specific characteristics of the lesion. For example, for tumors near the saddle area, we use the inferior frontal approach, the pterygoid approach or some modifications as appropriate; for tumors in the oblique area, we usually use the anterior sigmoid sinus or the combined supramural and submural approach. We have also successfully resected medulloblastoma with extensive involvement of the fourth ventricle, cerebellar earth, brainstem and one cerebellar peduncle using the inferior median occipital approach, while the posterior sigmoid sinus approach is mostly used for tumors in the pontocerebellar cerebellar angle and pontineal area, and more tumors in the pineal area can be used as appropriate. For tumors closely related to brainstem such as brainstem itself or glioma invading brainstem, excessive removal of tumor may damage brainstem and cause respiratory disorders. Especially for those involving medulla oblongata or malignant tumors, total resection or near-total resection of tumors should not be pursued. 2.For meningioma, nerve sheath tumor and cholesteatoma in oblique area, cerebellopontocerebellar angle area (CPA area) and occipital foramen area, they are generally separable from brainstem and basilar artery, so attention should be paid to differentiate and protect the surrounding cranial nerves. However, for tumors with tight adhesion to brainstem and important blood vessels, brainstem soft meninges with edema and large and hard tumors, total resection is very difficult and may cause serious complications, so do not force total resection. For gliomas that widely involve the fourth ventricle, cerebellar earth, brainstem and cerebellar peduncle, total resection or near total resection of the tumor is also possible through a simple inferior median occipital approach. At the same time, due to the extensive damage to the deep nuclei of the cerebellar hemispheres and cerebellar peduncles in this type of surgery, mutism may occur after surgery. 4.When resecting tumor, generally deal with the base of tumor or main blood supply side first. When dealing with blood vessels, pay attention to protect the main trunk and small branches supplying brainstem, and should coagulate close to tumor to cut off the tumor supplying blood vessels. 5.When resecting tumor, intracapsular resection can be done first to leave space for separating tumor edge. When separating the tumor, pay attention to using the discovered normal tissue interface to guide the separation. At the same time, pay attention to using multiple angles and directions for separation in order to fully remove the tumor and maximize the protection of the adjacent important brain structures. Due to the improvement of microscopic technology and the increasing rate of tumor resection, for patients with preoperative ventricular access obstruction and hydrocephalus, the shunt or ventricular drainage used in the past is less and less used now. For these patients, if we think that the tumor has been completely resected or nearly completely resected and the ventricular access obstruction has been lifted sufficiently, we usually do not perform shunt or extraventricular drainage, but perform dural repair and suture, and no hydrocephalus has been aggravated after the operation and need to perform hydrocephalus shunt again.