In cervical spine surgery, tumors in the cervical spinal canal are not uncommon. Tumors are prone to spinal cord compression, with high rates of paralysis and disability, and even life-threatening. In recent years, with the promotion and application of modern imaging technology and advanced surgical procedures, more and more hospitals in China have carried out the diagnosis and treatment of cervical spinal canal tumors in spine surgery, and many reports in the literature show that the diagnostic accuracy and surgical efficacy are generally good, but misdiagnosis, missed diagnosis and surgical complications occur from time to time, thus affecting the surgical efficacy and even causing serious consequences. Therefore, how to improve the diagnosis and treatment of cervical spinal canal tumors is worthy of our attention and attention. First, we should be familiar with the guiding significance of classification on diagnosis, treatment and prognosis. Cervical spinal canal tumors can originate from various tissues in the spinal canal, such as spinal cord membrane, nerve roots, spinal cord, blood vessels, spinal canal wall tissues and embryonic residual tissues. Clinically, cervical spinal canal tumors are usually divided into three categories according to the relationship between tumors and spinal cord and dura mater, namely, intramedullary tumors, extramedullary subdural tumors and intradural epidural tumors. 1.Intramedullary tumors account for about 10%-20%. They mainly include astrocytoma and hemangioma. Among them, astrocytoma is a malignant tumor with poor prognosis. Because the tumor is located in the spinal cord and invades the spinal cord, the spinal cord function is often significantly damaged before surgery, and the removal of the tumor may cause or aggravate spinal cord injury. The possibility of postoperative paraplegia and aggravation is high. Therefore, preoperative efforts should be made to make a clear diagnosis and not to operate on it as an extramedullary subdural tumor. At the same time, it is recommended that for such tumors, surgery is best performed in cooperation with neurosurgeons, applying microsurgical techniques to separate and remove the tumor to minimize the occurrence of complications. 2. Extramedullary subdural tumors account for about 60%-70%. They mainly include nerve sheath tumor, neurofibroma, spinal meningioma, etc. They are mostly benign tumors with slow growth and good prognosis. For these tumors, emphasis should be placed on complete removal of the tumor while preserving the function of the spinal cord and nerve roots as much as possible to reduce the recurrence rate. Intradural epidural tumors account for about 10%-20%. They include benign tumors and malignant tumors. The former is mainly neurofibroma, lipoma and hemangioma. It is relatively easy to remove the tumor completely. The prognosis is good. The latter are mostly metastatic tumors, lymphoma, etc., with poor prognosis. Attention should be paid to finding the primary focus and choosing the treatment method according to the situation. If the general condition of the patient is good and the bone destruction is limited, surgery is feasible. After surgery, radiotherapy or chemotherapy should be used as a supplement. Second, the value of understanding clinical features for early diagnosis and surgical decision. Intracervical spinal canal tumor often has no typical clinical manifestations, and its early diagnosis is often difficult. In addition, it is difficult to differentiate from other spinal cord disorders and spinal cord compression due to numbness of upper limbs, radiating pain, intrinsic hand muscle atrophy, weakness of lower limbs, unstable gait, positive cone bundle sign and bladder sphincter dysfunction caused by compression of spinal cord, nerve roots and surrounding tissues. 1. Clinical characteristics of upper cervical spinal canal tumors. The upper cervical spine (C1-C2) is the occipito-cervical junction, with special and complex anatomical structure. The intracanalicular tumor located in this area has the following clinical characteristics:1 Because the canal cavity is larger than the lower cervical spine, there is a large compensatory gap, so when the tumor is small, it is not easy to detect, and when it is detected, the tumor is often large. Therefore, for those who have chronic progressive pain in occipital cervical region and nocturnal pain, cervical MRI should be performed in time to make a definite diagnosis as early as possible.2 The upper cervical spinal canal contains the continuation of spinal cord and medulla oblongata, which is an important structure closely related to the respiratory and heartbeat centers, and intravertebral tumors located in the upper cervical spine are larger in size and more closely adhered to the surrounding tissues, so it is often difficult to separate and remove the tumor. Especially for tumors located in the ventral side, they may affect the respiratory and heartbeat functions and even endanger the life during surgery. 2. Clinical characteristics of lower cervical spinal canal tumor. Intracanalicular tumors in the lower cervical spine (C3-C7) have the following clinical characteristics:1 Because the lower cervical spinal canal is smaller than the upper cervical spine, the cervical medulla is thicker, and the compensatory gap is smaller, the symptoms appear early and the radicular symptoms are heavy after the tumor occurs. Attention should be paid to differentiate it from other cervical spine disorders and spinal cord compression, and MRI examination of cervical spine should be performed in time. We have encountered many patients who did not see any abnormal changes in general cervical MRI examination, but found tumors after performing enhanced MRI examination. Therefore, in order to prevent missed diagnosis, enhanced MRI should be performed when necessary for patients with suspicion.2 For tumors in the lower cervical spine, the spinal cord and nerve roots are easily damaged when separating and removing tumors due to the small size of the spinal canal cavity. Therefore, we should strive to be meticulous and delicate to achieve the requirement of complete removal of tumor without damaging spinal cord and nerve roots. Mastering the key points and techniques of surgery is the key to ensure the efficacy and prevent complications. 1. The operation should be performed under general anesthesia intubation. Removal of cervical spinal canal tumor usually requires prone position, and the operation time is long, which may affect the respiratory and circulatory system during the operation, especially the removal of upper cervical spinal canal tumor is more prone to accidents. Therefore, intraoperative anesthesia management is very important. To ensure that the operation can be completed safely and smoothly, it should be emphasized that the operation must be performed under general anesthesia intubation. 2.Cutting off the dentate ligament. The dentate ligament is located on both sides of the cervical medulla and is triangular in shape, starting from the soft spinal membrane, and its tip crosses the arachnoid membrane and ends at the inner surface of the dura mater. It has a fixed effect on the cervical medulla and prevents swinging from side to side. When performing extramedullary subdural tumor resection, in order to avoid excessive strain on the cervical medulla when separating and removing the tumor, the dentate ligament in the surgical area should be cut. However, when cutting the dentate ligament, care should be taken to reveal and operate carefully to avoid damaging the spinal cord and nerve roots. 3. Retraction and filling techniques. When separating and removing the tumor located in the extramedullary subdural or intradural canal, after partial exposure, the tumor should be held by sutures on the tumor envelope, then start from below or above the tumor, and gradually separate to the surrounding. At the same time, the tumor should be separated and filled with gelatin sponge while under draping, so that it is not only beneficial to resect the tumor, but also can achieve the purpose of hemostasis. Especially for large tumors, because of the large space left after resection, it is often difficult to stop bleeding and bleeding during surgery. If gelatin sponge is used to fill the tumor at the same time of resection, it can achieve satisfactory hemostasis effect. 4.Dumbbell-shaped tumor should be operated in stages. The nerve sheath tumor located in the cervical spinal canal can grow along the nerve root and cross the intervertebral foramen to reach outside the spinal canal, forming a dumbbell shape. In the past, some scholars advocated that for such tumors, if complete resection is difficult, only the part inside the vertebral canal can be removed, while the part outside the intervertebral foramen can be preserved to avoid adverse consequences due to damage to the vertebral artery and vertebral vein. In addition, such tumors grow slowly and the whole laminectomy and decompression have been performed during surgery. In recent years, with the continuous improvement of modern imaging technology and surgical methods, as well as the continuous progress of intraoperative anesthesia management and postoperative ICU, the above-mentioned view has been questioned. Currently, most scholars advocate that for this type of tumor, the tumor should be removed by a one-stage anterior-posterior approach or a staged anterior-posterior approach. Although there have been many successful reports of tumor resection by one-stage anterior-posterior surgery. However, it is considered that these tumors are benign and slow-growing, so in order to ensure surgical safety and reduce complications, it is appropriate to remove the tumor by staged anterior and posterior surgery. Depending on the location and size of the tumor, posterior or anterior surgery can be performed first, and then anterior or posterior surgery can be performed three weeks later. 5.Reconstruction of occipital neck stability and selective internal fixation of lower cervical spine. It is very important to reconstruct and maintain the stability of the cervical spine after removing the tumor in the cervical spinal canal. Removal of tumors in the upper cervical spinal canal often requires removal of the posterior arch of C1 and the C2 lamina, and occipitocervical instability can occur after surgery. Therefore, occipitocervical fusion internal fixation should be performed at the same time as resection of the upper cervical spinal canal tumor. In recent years, many reports in the literature have confirmed that occipitocervical fusion internal fixation has an important role in reestablishing occipitocervical stability, especially anti-rotation. Total laminectomy is required to remove tumors in the lower cervical spinal canal. At present, it is still debated whether internal fixation is needed to rebuild stability after total laminectomy. However, many scholars believe that stability reconstruction should be considered if more than three laminae are removed. In recent years, many studies have demonstrated that cervical lateral block screw internal fixation is an effective method to maintain cervical curvature and prevent kyphosis after laminectomy.