Syringomyelia is classified into two subtypes on the basis of its cavitary patterns; central canal dilation type and arenchymal cavity type without central canal dilation. Chiari malformation, hydrocephalus, adhesive arachnoiditis, fauma or intramedullary tumors are considered to be the common etiology of syringomyelia. However, the mechanisms of syrinx formation remain unclear. We performed morphological and histological studies of the parenchymal cavity type syrinx brought on by a crush injury in experimental rat models in order to elucidate the mechanism of posttraumatic syrinx formation. The spinal cords of Wister rats were injured by epidural pinching with an aneurysm clip at the middle thoracic level. Rats were killed 12 hours - 16 weeks later. The spine and spinal cord were removed en bloc and sectioned transversely after fixation with Folmaldehyde. The transverse sections were treated with Hematoxylin-eosin stain and histological findings were observed timewise. The rate of syrinx fomation in these models after more than 2 weeks was very high (12/14). The histological findings were transverse damage at the injury level (1-2 segments), cavity formation in the posterior funiculus both rostrally and caudally (total 5-9 segments), local bleedings in the posterior funiculus in the early stage from 1 to 10 days, and gliosis and reactive astrocytes and macrophages around the cavity in the late stage after 12 weeks. Syrinxes of this injury model were formed even on day 14 and had a tendency to be clear in margin and large in size timewise. They were considered to have originated from necrotic microcystic cavitation in the spinal cord parenchyma due to the primary injury and to have formed into large syrinxes in the degenerated fragile posterior funiculus because of the injury and the associated changes of the spinal cord. Cavitation of this experimetal model is likely the early pathological change of traumatic syringomyelia. This cavitation seems to derive from parenchymal degeneration which is resistant to treatment including surgery.

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Most of the recent reports have suggested that cerebro-spinal fluid (CSF) flow disturbed by herniated cerebellar tonsils induces syringomyelia in adult type Chiari malformation. We investigated CSF flow dynamics at the foramen magnum using cine magnetic resonance imaging (cine MRI), to quatitatively estimate the improvement of CSF flow at the foramen magnum before and after decompressive surgery. Quantitative cine MRI was performed in 18 patients suffering from syringomyelia with Chiari malformation and 5 normal volunteers to evaluate CSF flow dynamics. As useful indices, we measured the maximum caudal flow velocity (max. flow velocity) and calculated the timescale of the maximum flow velocity to one cardiac cycle (% cardiac cycle). In all of the 18 cases who underwent expansive suboccipital cranioplasty, the neurological findings and syringomyelia improved after surgery. Before surgery the max. flow velocities in patients were significantly diminished in magnitude at the foramen magnum, compared with those in normal subjects. Before surgery the % cardiac cycles at the foramen magnum in patients were significantly diminished in quickness, compared with that in normal subjects. After surgery, the max. flow velocities and the % cardiac cycles approximated those of the normal controls. Thus, expansive suboccipital cranioplasty can effectively restore the disturbed CSF flow at the foramen magnum, and consequently result in reduction of the syrinx size. To-and-fro motion of the fluid in the syringomyelia before surgery diminished after surgery. We concluded that, to estimate the efficacy of surgical treatment, CSF flow dynamics at the foramen magnum should be evaluated. Cine MRI could be useful to study the progression of syringomyelia.

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Anterior fusion of cervical spine with screw-plates is gaining popularity in the management of anterior cervical spine instability. We report our surgical results with anterior cervical fusion using constrained and non-constrained plate system. Pathology included cervical spondylosis in 40, cervical spine trauma in 66, cervical disc disease in 43, and ossification of posterior longitudinal ligament in 3 patients. 152 consecutive cases, 110 men and 42 women, underwent discectomy and multilevel corpectomies or spondylectomies using a modified Smith-Robinson procedure with various plate systems, Caspar plate in 14, Top plate in 102, and Orion plate in 21 patients. 15 patients underwent surgery without plate system. The mean follow-up period was 17 months (range 12-30 months). Dislodgement of bone graft or screw loosening and fusion failure that required reoperation occurred in 8 patients. All of these cases are those operated using non-constrained system or without plate system. However, in the group with the constrained system we did not observe any hardware-related complications and the fusion rate was 100% during the follow-up period. Anterior cervical fusion with screw-plate system can be carried out with acceptable complication rate. We conclude that the use of the constrained plate system yields better results than the non-constrained system, and it is a safe and effective method to provide reliable stabilization of the cervical spine.

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<Background> Although the complications due to acupuncture are rare, twenty-one cases with spinal cord injury as a complication of acupuncture have been reported. However, intradural hematoma causing Brown-Sequard syndrome has not been described previously. <Clinical presentation> We report a case of intradural hematoma in the left hemicord at the C3-4 level on MR images after acupuncture therapy. The patient developed Brown-Sequard syndrome. On exploration with C3-4 osteoplastic laminotomy, the hematoma was located in the subarachnoid space, and was presumably caused by injury of perimedullary vein. The patient fully recovered except moderate right thermohypesthesia. <Conclusion> Brown-Sequard syndrome due to the penetrating cord injury by acupuncture needle in this case was not caused by direct injury but by venous bleeding followed by unilateral compression of the cord by intradural hematoma.

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The authors report the case of a 27-year-old woman who presented with an intracranial acute epidural hematoma following removal of a cervical intramedullary astrocytoma, 10 weeks after the delivery of a child. Intraoperative findings showed no skull fracture or perforation by the headrest pins. The cause of the hematoma might have been the detachment of the dura mater from the skull at the site where her head was in a fixed position, which may occur easily in the postpartum period.

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Spinal hemangioblastoma rarely cause intramedullary hemorrhage. We report a case of hemangioblastoma with intramedullary hemorrhage and review previous reports. A 71-year old man suddenly incurred consciousness-disturbance and tetraparesis. He came to our hospital by ambulance. CT and MRI showed intramedullary hemorrhage from the lower medulla oblongata to the C3 level. The right vertebral angiogram revealed hemangioblastoma fed by the anterior spinal artery at the level of C1. In consideration of the patient's age and general condition, surgical treatment not used. Instead, mega-dose steroid and osmotic diuretics administration was performed along with hyperbaric oxygen therapy. The right vertebral angiogram after 6 month after onset revealed remarkable reduction of tumor size. His symptoms improved gradually and he is now independent in his daily living activity.

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We developed a new technique for laminoplastic surgery for thoracic spine by utilizing a high-speed drill and titanium miniplates. A 51-year-old woman suffered thoracic pain followed by paraparesis. Both MRI and CT scans disclosed irregularly-shaped extra and intramedullary cystic lesion from Th-7 to Th-9. At surgery, en bloc laminotomy was performed from Th-6 to Th-10. By using a high-speed drill, bilateral laminotomy was able to be carried out. Because at the thoracic level, the lamina overlie each other and the width is very narrow, careful bone drilling is necessary. The cystic lesion was found to be the result of arachnoiditis possibly caused by previous myelography for lumbar disc disease. The cystic wall was fully opened. The lamina was replaced in situ and fixed with titanium miniplates for skull fixation. Over a follow up period of 10 months, the patient has been doing well with good spinal stabilization. This technique can be used as one of the alternatives for thoracic laminoplastic surgery.

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The threaded Fusion Cage (TFC) is a very useful device to eliminate spinal segmental instability and restore disc height. We report here that TFC is also very useful for treating degenerative lumbar scoliosis. A 48 year-old woman had been suffering from pain in the left lower extremity for thirteen years. She finally became unable to walk because of increasing pain during the previous eight months. She had degenerative lumbar scoliosis at L4-L5 and hypolordotic spine with congenital thoracic scoliosis. The degenerative lumbar scoliosis consisted of disc degeneration and difference in the height of the right and left sides of the vertebral body. Decompression and posterior lumbar interbody fusion with two different-sized TFCs at L4-L5 were carried out. Twenty-one days after surgery, the pain in the left lower extremity disappeared and she became able to walk by herself. Postoperative roentgenograms showed that the degenerative lumbar scoliosis had disappeared, but that the tilt of the lumbar spine compensated for the thoracic scoliosis had not been corrected. At the follow-up 10 months after surgery, she was asymptomatic and solid fusion was radiologically observed on flexion as well as on extension of the lumbar spine. This case shows that placing two cages of different size in a single space is very useful for acquiring tight fusion and restoring the alignment of the lumbar spine when there is a difference in the height of the right and left sides of the vertebral body.

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Idiopathic spinal cord herniation is an uncommon clinical problem. The authors report a case of spontaneous herniation of the spinal cord in a 56-year-old man who presented with an unexplained, longstanding spastic paraparesis. Ventral spinal cord displacement with no apparent dorsal mass was noted at the Th2-3 vertebral level on magnetic resonance imaging and computed tomography following myelography. The dural defect and the herniation of the spinal cord were confirmed at operation. The herniated spinal cord was mended intradurally, and the dural defect was closed primarily. Postoperatively, the patient showed neurological recovery. Idiopathic spinal cord herniation is a treatable cause of myelopathy that may be more common than is currently recognized and should be known to all surgeons managing spinal disorders.

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