Background : In neurosurgery and spine surgery in particular, the unique risks and benefits of utilizing different prophylaxis regimens against deep venous thrombosis (DVT) and pulmonary embolism (PE) must be carefully weighed. Our aim was to comprehensively review the safety and efficacy of different regimens of prophylaxis against DVT and PE in neurosurgical cranial and spinal studies.
Methods : Patients undergoing cranial or spinal procedures may receive one or more types of prophylaxis; elastic stockings (ES), intermittent pneumatic compression stockings (IPC), low dose unfractionated subcutaneous heparin (typically 5000 U q12h), and/or low dose low molecular weight heparin alternatives. The incidence of DVT, PE, and hemorrhage, particularly for those receiving low dose fractionated or low molecular weight heparin, were reviewed.
Results : IPC stockings appeared to be very effective, particularly in spinal surgical series where the frequency of DVT/PE remained lower than in cranial studies. Although the addition of low dose unfractionated subcutaneous or low dose low molecular weight heparin regimens further decreased the frequency of DVT and PE, it carried a 2%-4% risk of major postoperative hemorrhage.
Conclusions : Intermittent compression stocking prophylaxis (IPC) alone provide adequate prophylaxis against DVT and PE in most patients undergoing spinal procedures. The “value added” of low dose unfractionated subcutaneous or low dose low molecular weight heparin regimens regarding further reduction in the incidence of DVT and PE, poses the significant risk of major postoperative hemorrhage.

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It has been controversial whether surgical treatment for retro-odontoid mass including disc hernia is indicated. We surgically treated 8 patients with retro-odontoid mass. We discuss clinical characteristics, therapeutic strategies, the genesis based on histological findings, and problems of post-operative care in this lesion.
Age distribution of the patients was from 77 to 86 years old (mean: 81.0 years). Male/female ratio was 6/2. All patients showed neurological deficits due to myelopathy. Pre-operative magnetic resonance (MR) imaging showed an isointensity mass at the retro-odontoid space. Only marginal enhancement was seen in 2, and heterogenous enhancement in 6 patients.
All patients underwent surgery via postero-lateral transdural approach for removal of the extradural retro-odontoid mass. All patients showed neurological improvement, however, severe neurological deficits still remained in 2 patients who had been in bed-ridden pre-operatively. The surgical specimens consisted of degenerative cartilaginous tissue and reactive fiborvascular tissue.
As the retro-odontoid mass contains various pathological lesions, histological confirmation is necessary. Among reported surgical approaches, the postero-lateral transdural approach is less invasive, especially for high elderly patients. A source of cartilaginous tissue is probably derived from the herniated disc penetrated posterior longitudinal ligament at C2/3, which has migrated upward to the retro-odontoid space. Not only such migration, but also some proliferative change might come to form the retro-odontoid mass.
Retro-odontoid mass is characteristic in very elderly patients. Elderly patient-specific problems such as disuse atrophy due to less movement and painful arthrosis deformans in the lower extremities prevent successful rehabilitation. Earlier planning to advance rehabilitation in cooperation with neurosurgeons, orthopedists, and rehabilitation physicians is necessary for very elderly patients' quality of life.

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Background: Recently, there has been a rapid increase in the use of titanium cervical spine interbody fusion cages as an adjunct to anterior cervical decompression and fusion. There are few reports about the histological and mechanical properties of the titanium cages. The purpose of the present study is to evaluate the histological analysis and removal torque of porous micro-cages (PC) and non-porous micro-cages (NPC) and compare them.
Methods and Results: The PC and NPC were inserted in the tibia of rabbits. The tibiae containing the implants were harvested at 4, 8, and 12 weeks after implantation and histological, microradiographical and mechanical evaluations were performed. Histologic examination by Hematoxylin-Eosin staining and contact microradiography (CMR) revealed that a direct bone-to-implant contact was found during early post-implantation in PC groups, whereas soft tissue was observed on the surface of NPCs even 12 weeks after implantation. After a healing time of 4, 8, and 12 weeks the average removal torques were 0.091±0.03, 0.096±0.055, and 0.156±0.05Nm for NPC groups, 0.129±0.068, 0.217±0.118, and 0.423±0.093Nm for PC groups. In PC groups, there was a gradual increase of removal torque value with the increasing time of follow-up. The difference between NPC and PC groups was not significant at 4 weeks but was significant at 8 weeks (P<0.003) and 12 weeks (P<0.0001) after implantation.
Conclusion: The PC groups achieved higher removal torque values compared to the NPC group, and these values might be related with the higher bone-to-implant contact. Therefore, PC might have higher fixation than NPC from early stages.

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We report the results of surgical treatment of lesions in the cranio-vertebral junction and qualify the decision to use a surgical approach.
40 cases were treated. In consideration of the location of the lesion, relationship to lower cranial nerves and vertebral artery, some cases were added large suboccipital craniotomy, condylar resection and/or resection for transverse process of atlas and axis. We could remove the lesion totally in 88% of the cases. All of the cases had improvement in neurological symptoms. Subtotal removal was performed in three cases, because the tumor had adhesion to the brain stem or lower cranial nerves.
For the lesions in the craniovertebral junction, the basic approach was dorsolateral approach, for the lesion extending to the spinal canal was performed hemilaminectomy of the atlas and axis. In consideration of the location of the lesion, the relationship to lower cranial nerves and the vertebral artery, suboccipital craniotomy, condylar resection and/or resection of transverse process of the atlas and axis should be added. For the intramedullary lesion, we should make the approach more laterally to get to the lesion directly.

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Background;
Spinal cord hemangioblastoma (HB) is a well circumscribed intramedullary tumor, predominantly located in the dorsal subpial layer of the cord. Occasionally a deeply and/or ventrally located HB presenting some surgical difficulties is encountered.
Purpose of this study;
The authors divided HBs into two groups; dorsally and superficially located one (dorsal type), and deeply and/or ventrally located one (deep type). This study was conducted to evaluate clinical differences of these two types and to propose several surgical techniques in terms of extirpating the deep type.
Materials and results;
Nine consecutive HBs including 3 dorsal and 6 deep type were evaluated. No apparent differences were noted in patient's age distribution and gender as well as tumor locations in the two groups. However, deep type had shorter preoperative period with positive motor disturbance and exhibited larger size, associated with long T2 lesions next to the tumor. All tumors were totally removed. Via posterior midline spinal cord splitting subsequent to osteoplastic laminotomy was employed to extirpate the deep type tumors, 4 cases of which experienced transient postoperative neurological deteriorations lasted within a few months.
Discussions;
The deep type has different biological behaviors compared with the dorsal type. While proposing other approaches to a deep type such as an anterior approach, a posterolateral approach and the midline posterior approach is another main route to access and remove the tumor. To complete this surgical procedure with minimum morbidities, some surgical techniques are proposed; Preoperative embolization of the feeding vessels if possible, wider opening of the dorso-medial sulcus cephalad and caudal to the tumor, obtaining earlier exposure of tumor cysts, meticulous dissection on the tumor plane, coagulation and reducing the volume of tumor to perform an “en block” fashion removal, and careful detachment of small vessels from the anterior medial fissure on the spinal piamater and of the ventral roots. Functional monitoring of spinal cord function is mandatory during surgery.

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To clarifry the ideal surgical timing for cervical cord injury, we analyzed twenty-four patients exhibiting this injury. Twenty patients were men and four were women. Early surgery within 7 days of trauma was performed in seven cases and surgery in subacute stage during 8 to 14 days from trauma was performed in eight cases. The other seven cases were operated as a late surgery group over 14 days from trauma. While thirteen cases had fractute or dislocation of cervical vertebrae, the other eleven cases were without bone damage.
Sixteen cases of the 24 improved symptomatically judging with the Frankel grade. Eight cases did not improve. We checked the exact cause of these cases.
The result of some cervical cord injuries have good outcomes with surgery in subacute stage or late surgery after preserving cervical stability. Early surgery is considered to be more effective in other patients, especially in the cases with bone damage and cervical cord compression showed by MRI. Attention to the timing of surgical intervention is important in cases of cervical cord injury.

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STUDY DESIGN: Surgical technique for the cauda equina tumors.
MATERIALS AND METHODS: 10 patients with cauda equina tumors were treated surgically. There were 6 men and 4 women, with ages ranging from 33 years to 76 years. In all 10 cases, schwannoma were exhibited in 7 patients, ependymoma was exhibited in 1 patient, mixed-glioma was exhibited in 1 patient and metastatic tumor was 1 patient. In the 7 cases of schwannoma, 2 cases were giant schwannoma. All patients presented with lumbago or pain of lower extremities. 1 patient had an emergency operation performed. Complete tumor resection was possible in 8 cases (schwannomas and ependymoma), and subtotal tumor resection (more than 90%) was done in 2 patients (mixed-glioma and metastatic tumor).
OUTCOME: All patients had good outcomes after operations.
CONCLUSION: It is very important to make a good approach with resection of cauda equina tumors, especially, giant schwannoma/ or metastatic tumors.

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The patient is 55-year-old female, consulting her physician because of lumbago as the chief complaint. She was hit by a motor vehicle at 12 years of age and suffered a severe impact on her back. She developed lumbago in July, 2003 and an MRI revealed the pathology of compressed thoracic spine anteriorly. The mass showed low intensity on T1WI and high intensity on T2WI from Th9 to L1 at the dorsal side. On admission she had difficulty with sensorimotor disturbances; interimittent claudication and impairment of sense of temperature and touch in the lower extremities. Surgical intervention was performed to reduce her symptoms; osteoplastic laminoplasty expanding Th11 to L1 and application of the dura synthesis (Th10) was done to close the dural defect and reduce her symptoms. The thoracic spinal extradural meningeal cyst is rare in that it took more than 40 years to develop from the onset. In this report we covered a rare case with spinal thoracic extradural meningeal cyst improving the symptom after surgery.

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The finding of gas in the intervertebral disc space, known as the “vacuum phenomenon” is common on radiographic studies of the lumbar spine. Whereas intraspinal epidural gas or gas-containing lumbar disc herniation are rarely observed; and fewer than 30 cases have been reported in recent literatures. We report two cases of women who experienced unilateral sciatica, and confirm an intraspinal gas pseudocyst radiographically and surgically. Referring to the literatures, intraspinal epidural gas can be classified into three categories;
i) Intraspinal free gas.
ii) Intraspinal gas pseudocyst, of which the cyst wall reveals nonspecific fibrous tissue identical to the ligament itself histologycally.
iii) gas-containing disc hernia, in which the wall reveals the intervertebral disc itself.
The second and the third conditions cause radicular pain.

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For perivertebral tumors, preoperative evaluation of tumor localization and selection of operative procedures are important. A two stage operation, one stage operation with or without thoracotomy, or a posterior approach with thoracoscopy are reported for these kind of tumors. In this report, we demonstrate thwo cases of Eden 4 type neurinoma successfully resected by costotransversectomy without thoracotomy. In these cases, tumors are removed without any perioperative complication. When tumor size and localization are appropriate, this procedure should be considered for perivertebral tumors.

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