The diagnosis and treatment of multiple intradural tumors that are not neurofibromatosis are not yet reported. From February 2002 to November 2007, 15 cases of extramedullary subdural multiple tumors were admitted to our department, accounting for 4.1% (15/369) of the intradural tumors admitted during the same period, which are reported as follows. I. Clinical data and methods 1. General data: In this group of 15 cases, there were 11 male and 4 female cases. Age ranged from 16 to 81 years, (51.0±21.2) years. The duration of disease was 2 to 27 months, (11.0±7.6) months. The first symptom was radicular pain of the limbs in 6 cases, numbness in 2 cases, lumbar and leg pain in 4 cases, and weakness of the limbs in 3 cases. There were 8 cases with urinary and fecal disorders. There were 8 cases of decreased muscle strength, 10 cases of sensory impairment, 2 cases of muscle atrophy, 7 cases of hypotonic and 2 cases of hyperactive tendon reflexes in the lower limbs, and 2 cases of positive Bartholin’s sign. There was no family history, history of malignant tumor, skin café au lait and somatic neurofibroma, and no abnormality in cranial MR. Preoperative KPS score. Imaging data: enhanced MR showed 46 intradural extramedullary subdural tumors, 2 in 8 cases, 3 in 4 cases, and 5, 6, 7, and 1 case each. The maximum length of tumor diameter 6cm, ≥0.5cm tumor 35, tumor site, see Table 1. 1 case of multiple melanoma MR performance. (1) Surgical method: The tumor was resected by posterior median approach laminectomy, and the extent of laminectomy was decided according to the size of the tumor, with half laminectomy for <1cm and subtotal laminectomy for >1cm to preserve the small joints, and the tumor was removed from the nerve under the microscope. If the tumor cannot be separated from the nerve, the nerve root should be freed as much as possible and the nerve root should be anastomosed after resection. (2) Postoperative treatment: postoperative antibiotics and hormone therapy were routinely applied, and postoperative cervical collar and waist protection were worn for 2 months, and the muscles of the low back were trained at the same time. Postoperative pathology is malignant tumor radiotherapy and chemotherapy, postoperative outpatient or telephone follow-up to understand the recovery of neurological function of patients. Among the 15 cases, 12 cases had complete resection of the tumor; 3 cases did not have complete resection, among which 2 cases were not considered for surgical resection because the tumors were far apart and the diameter was <0.5 cm without corresponding clinical symptoms, and the other case saw intraoperative adhesion between the tumor and multiple nerve roots. A total of 33 tumors were resected, and 21 nerve roots were preserved, including one with nerve root anastomosis. The postoperative KPS scores recovered in all 13 survivors, 75.4±13.3 before surgery and 97.7±6.0 at the last postoperative follow-up, paired t-test, t=-7.366, P=0.000. One case had numbness in the lower limbs and difficulty in urination after surgery, but urination was normal at the follow-up 3 months later. Pathology: nerve sheath tumor in 8 cases (53.3%), neurofibroma in 1 case (6.7%), ventricular meningioma in 2 cases (13.3%), melanoma in 1 case (6.7%), adenocarcinoma metastasis in 1 case (6.7%), spinal meningioma in 2 cases (13.3%). 1 case was clinically diagnosed as spinal meningioma with multiple nerve sheath tumors. All 15 cases were followed up after surgery, except for the melanoma patient who died 22 months after surgery and the metastatic tumor patient who died 1 year after surgery, the remaining 13 cases were followed up for 4 to 72 months, with an average of 30.1 months, and there was no recurrence of tumor growth. 1. Diagnosis: Multiple intravertebral tumors are mostly seen as neurofibromatosis, which can be divided into type I and type II according to different genotypes and clinical manifestations, and there is no effective treatment method yet. This group does not have corresponding clinical manifestations, and the pathology is mostly nerve sheath tumor. Some scholars believe that such multiple intraspinal nerve sheath tumors should be named as nerve sheath tumor disease, whose pathogenesis is still unclear. The average age of this group is about 50 years old, and the duration of the disease is 2 to 27 months. Patients with malignant tumors or tumors located in the thoracic segment have a short course and progress rapidly, and most of them have neurogenic pain as the first symptom. Because the lesions can be located at different stages of the spine, they often present as upper motor neurogenic damage of the limbs combined with lower motor neurogenic damage and damage to multiple spinal nerves, which are often misdiagnosed as intervertebral disc disease due to diagnostic difficulties. We believe that MR examination of the whole spine and skull should be performed for suspected multiple intravertebral tumors, especially for patients with upper motor nerve damage, to exclude other tumors. Most multiple intravertebral tumors are not difficult to diagnose correctly on MRI. Intraspinal tumors are more common in the thoracic spinal canal, and in this group of cases, they are more common in the thoracolumbar segment, followed by the lumbosacral segment. This group of cases suggests the following points to note: ① For those who cannot explain the clinical manifestations by imaging, although there is no manifestation of neurofibromatosis, the presence of multiple tumors should be considered, and MRI scans of other parts of the spinal canal should be performed to provide more diagnostic information. ②Small nerve sheath tumors or fibrous tumors and small isosignal spinal meningiomas are often missed on MRI plain scan, T2-weighted images often suggest the presence of lesions, and enhanced small lesions can be found on enhanced scans; ③Melanoma is often diagnosed preoperatively due to its special short T1 and short T2 performance, and one case in this group was diagnosed preoperatively based on MR performance; ④Ventricular meningiomas in the lumbar spinal canal are mostly closely related to the end filaments, and enhanced The tumor is closely related to the end filaments, and the enhanced image of the tumor can help to make a clear diagnosis. ⑤ The current resolution of MR can diagnose tumors with a diameter of <0.5 cm by enhancement scanning. In addition, intraoperative exploration under the microscope can help to reduce the missed diagnosis. 2.Surgical indications: It is generally considered that larger tumors are the responsible lesions. For benign lesions non-neural origin tumors - spinal meningioma - should be surgically removed in one stage; while for nerve sheath tumors and neurofibromas of neural origin, as tumors often involve multiple nerves, surgical removal may cause permanent loss of neurological function of the patient, surgery must take into account the neurological function and quality of life of the patient after surgery, and should be performed to relieve The surgery must take into account the patient's postoperative neurological function and quality of life, and should be performed to relieve symptoms and improve quality of life by removing the responsible lesion. We believe that tumors <0.5 cm without corresponding clinical symptoms can be observed, and it is not mandatory to remove all tumors in one stage. In this group, there are 2 cases with no new symptoms for 1 and 3 years respectively, and MR showed no significant growth of tumor. For malignant tumor, the tumor should be removed as much as possible, and full decompression of the vertebral plate, combined with postoperative radiotherapy, can effectively relieve the symptoms and improve the quality of survival. 3.Surgical method: Surgical resection is an effective treatment for intravertebral canal tumor. Yang Shuyuan et al. reported that the surgical efficacy of intradural neurofibroma and spinal meningioma is good. Surgery should be performed with minimal trauma to obtain maximum neurological recovery. The posterior median incision is generally used for the surgical approach, and the same incision can be used if the tumor is located in adjacent segments, or multiple incisions can be used if they are farther apart (more than 3 vertebral segments). For tumors less than 1 cm, a hemilaminectomy can be considered without damaging the small joints and minimizing the impact on spinal stability. Microscopic manipulation can clearly locate the tumor and isolate the blood supplying artery and the nerve carrying the tumor. If the tumor is tightly adhered to the nerve root or the nerve root penetrates from the tumor body, the tumor envelope should be cut longitudinally and the tumor can be removed in pieces within the envelope to further determine the relationship between the tumor and the nerve root. Do not cut the nerve roots at will, otherwise irrecoverable nerve dysfunction may occur. If the tumor-bearing nerve has to be sacrificed after careful investigation, electrocoagulation under low current can be used to observe whether the muscle is throbbing or not. If the tumor is extensively adhered to the dura, the dura should be removed together to prevent tumor recurrence. The defective dura mater should be repaired with artificial dura mater to avoid future arachnoid adhesions or scar tissue formation and compression of the spinal cord, which may affect the therapeutic effect. Nerve sheath tumors with cystic changes often have adhesions to the spinal cord, which can be carefully separated under the surgical microscope and can be fully resected. For intravertebral metastases and ventricular meningioma, in addition to removing the tumor and separating the adhesions as much as possible to relieve symptoms, decompression of the vertebral plate should be performed, and postoperative radiotherapy and chemotherapy should be administered according to the pathological results in order to preserve the most neurological function and the ability to take care of oneself during the patient's survival. It is generally believed that scoliosis is a common deformity, which is mostly seen in patients undergoing total laminectomy decompression, especially in the migrating parts of the spine such as the cervicothoracic junction and thoracolumbar decompression, and hemilaminectomy can effectively reduce the impact of surgery on spinal stability and is a better choice for surgery of multi-segmental intravertebral tumors. If total laminectomy decompression must be performed, internal fixation should be performed in one or two stages. In addition, postoperative rehabilitation is important to prevent the occurrence of postoperative spinal deformity. 4. Prognosis: In this group, pain and weakness were relieved after surgery, quality of life was improved, and no spinal instability occurred. We believe that patients with multiple intradural tumors should be closely followed for more than 5 years, and for recurrence and follow-up growth of tumors, re-operation should be considered. If patients cannot tolerate surgery, the literature reports that stereotactic radiosurgery may have improved their prognosis, with tumor control rate above 70%. In our opinion, intradural extramedullary subdural multiple tumors are mostly benign and common in middle-aged and elderly people, and microsurgical resection of sub-total lamina combined with hemi-lamina approach is an effective treatment method, and asymptomatic tumors <0.5 cm can be closely followed. ????