It refers to primary or secondary tumor lesions occurring under the dura and outside the spinal cord, accounting for about 65% of spinal cord tumors most of which are benign, commonly include 1 neurofibroma; 2 spinal meningioma. 1.Root pain stage: When the spinal nerve root is compressed and stimulated by the tumor, it causes radicular pain or abnormal sensation in the corresponding spinal cord segment. This symptom mostly appears in the cervical segment and cauda equina of the tumor. 2. Spinal cord compression stage: As the tumor keeps increasing, the spinal cord is compressed and pushed to a certain degree, resulting in partial loss of spinal cord function and the so-called spinal cord hemisection syndrome. It is a typical symptom in the process of extramedullary tumor development. 3.Spinal cord paralysis stage: If the spinal cord is not diagnosed and treated in time during the compression stage, the further development of the lesion will lead to complete paraplegia of the limbs below the corresponding tumor segment, combined with loss of deep and superficial sensation, spasm of the extensor and flexor muscles, and urinary and fecal disorders. The first symptoms and signs of the disease are often weakness or progressive paralysis of the limbs, and some patients have sensory disturbances and radicular pain symptoms or segmental motor muscle atrophy and autonomic dysfunction as the first discomfort. Diagnosis: Imaging examinations are mainly: MRI or CT scan; spinal arteriogram; myelogram, etc. can make diagnosis and analysis of this disease in different perspectives. Treatment: Once the diagnosis is clear, surgery should be performed as early as possible. The recovery of neurological function after surgery depends on: (1) the nature and growth site of the tumor; (2) the intraoperative technique; (3) the urgency of spinal cord compression; (4) the degree and nature of preoperative limb paralysis; (5) the spread of the tumor to the surrounding area.