Abstract: OBJECTIVE: To investigate the clinical characteristics and surgical treatment strategies of dumbbell-type tumors communicating within and outside the vertebral canal. METHODS: Thirteen patients, 8 males and 5 females, with an average age of 37.5 years, admitted from January 2004 to December 2006 with dumbbell-type tumors communicating within and outside the vertebral canal were retrospectively analyzed. The tumors were located in the cervical spine in 8 cases, in the thoracic spine in 1 case, and in the lumbar spine in 4 cases. Tumor nature: 11 cases of nerve sheath tumor, 1 case of malignant nerve sheath tumor, and 1 case of ganglion cell tumor. Tumor stage: 12 cases of stage III and 1 case of stage IV. Results: 8 cases were resected by combined approach (posterior median approach + anterolateral approach), 5 cases were resected by posterior median approach. 13 cases were completely resected, and 1 case was fixed and fused with the lesioned segment by posterior nail rod system. The postoperative follow-up ranged from 6 months to 3 years, with an average of 18 months. Five patients had enlarged sensory numbness and eight patients had improved motor function of the limbs after surgery. No tumor recurrence and no spinal deformity occurred. Conclusion: Most of the dumbbell-type tumors communicating inside and outside the spinal canal can be removed by using one-stage microsurgery, and the impact on the stability of the spine can be reduced by applying the hemilaminectomy technique, and the damage to the adjacent anatomical structures of the tumor can be reduced by applying the intracapsular segmental resection technique. Chen Zan, Department of Neurosurgery, Xuanwu Hospital, Capital Medical University Keywords: dumbbell tumor, microsurgery, one-stage surgery Conclusion: All 13 patients in this group were treated with one-stage surgery for dumbbell tumors communicating within and outside the spinal canal. The resection of the intra-vertebral canal portion of the tumor was performed with the hemi-laminectomy technique, which protected the stability of the spine to the maximum extent, but spinal fixation was required for cases in which the stability of the spine was significantly damaged. The extra-canal portion of the tumor was resected using an intracapsular segmental resection strategy with final separation of the capsule wall, effectively avoiding damage to adjacent tissue structures. Figure 1 The tumor ventral to the spinal cord was exposed by hemivertebral dissection Figure 2: Postoperative imaging after resection of a dumbbell-shaped tumor in the cervical spinal canal. a: The dumbbell-shaped tumor destroyed the pedicle and vertebral body. b: The tumor severely damaged the pedicle and enlarged the intervertebral foramen. c: The tumor was resected and posterior fixation and fusion of the adjacent segment on the affected side was performed Figure 3: Pre-operative and post-operative imaging of the intra-vertebral canal tumor communicating within and outside the C5-6 cervical spinal canal. a: Preoperative axial position MRI shows that the tumor is located inside and outside the spinal canal. It formed a dumbbell shape, destroying the left articular eminence, lateral mass and part of the vertebral body, and pushing forward the vertebral artery. b: Postoperative axial MRI showed total tumor resection. c: Postoperative CT showed the extent of hemivertebral plate resection. d: Lateral cervical spine X-ray plain film was reviewed 1 year after surgery and showed normal cervical physiological curvature. Figure 4: Preoperative and postoperative MRI of a dumbbell-shaped tumor communicating within and outside the L1-2 spinal canal. a: Preoperative MRI shows the tumor pushing against the renal hilum. b: Postoperative MRI shows a hemi-plate approach to remove the tumor, preserving the affected articular eminence.