We conducted a second survey in the form of an anonymous questionnaire distributed to all current members of the Japan Neurosurgical Society. This survey examined the change in clinical situation among Japanese neurosurgeons in the last six years in response to the reform resulting from the first survey, which was conducted in 1999. Although the establishment of subspecialties in the Japanese neurosurgical field has progressed favorably in the past six years, it is not sufficient. A shortage of manpower and delays in the creation of an educational curriculum have emerged as problems in the establishment of subspecialties. The number of surgeries in large hospitals increased steadily in the past six years. However, the number in small hospitals decreased and tended to be lame duck. The degree of satisfaction among Japanese neurosurgeons has not improved in the past six years, unfortunately. Dissatisfaction about the insufficient number of surgeries is the foremost complaint, as it was in 1999. Dissatisfaction with salary ranks higher in this survey than in the first one. To improve the position of neurosurgeons in Japanese society, we propose that Japanese neurosurgeons and the Japan Neurosurgical Society should be proactive in further establishing subspecialties by creating an adequate educational curriculum and by more appropriately distributing neurosurgeons according to community needs.

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Small AVMs in eloquent areas of the brain with a high surgical risk are the absolute indication for radiosurgery. Medium-sized, slender-shaped AVMs can occasionally be candidates for radiosurgery if their volume is around 10cm^3 by means of anteroposterior and lateral cerebral angiogram views. Because the risk of hemorrhage during the period between radiosurgery and obliteration is reduced by half, AVMs with repeated hemorrhages can also be an indication for radiosurgery. In the treatment of such lesions, the recommended margin dose is 20Gy for the treatment of lesions with a volume less than 10cm^3. For small AVMs in non-eloquent areas of the brain, surgical excision is the first choice of treatment, but radiosurgery for patients older than 55 years of age may be justified, although a small risk of hemorrhage remains even after angiographic obliteration.

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Steady-state free precession is widely used for ultra-fast cardiac or abdominal imaging. The purpose of this work was to assess fast imaging employing steady-state acquisition (FIESTA) and to evaluate its efficacy for depiction of any vascular contact in patients with facial spasm and trigeminal neuralgia. Twenty consecutive patients underwent a FIESTA sequence, and any vascular contact was subsequently evaluated. The 20 patients consisted of 6 cases of trigeminal neuralgia and 14 of facial spasm. In patients with vascular contact by artery, it was identified by both spoiled gradient-recalled acquisition in the steady state (spoiled GRASS : SPGR) and FIESTA. But in one of 2 patients with vascular contact by vein, it was only confirmed by FIESTA. Also, a prosthesis was recognized only by FIESTA, and SPGR was not capable of depicting it. This MRI sequence also permitted the visualization of the vascular contact by vein. It was thought that such preoperative information about individual patients would be useful for obtaining assured informed consent.

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Objective : We studied preoperative malignancy evaluation of glioma by thallium-201 SPECT (Tl-SPECT), proton MRS (MRS) and 18F-fluorodeoxy-glucose PET (FDG-PET). Methods : Twenty-seven patients with astrocytic tumors (diffuse astrocytoma (A) : 8, anaplastic astrocytoma (AA) : 10, glioblastoma (GB) : 9) were retrospectively studied. FDG-PET was assessed as the visual metabolic grading scale (MG Scale) in 9 cases. The Tl index was expressed as the count rate of the tumor site to the count rate over the contralateral normal region in 25 cases. MRS was evaluated as the metabolite ratios of choline/creatine (Cho/Cr) and Cho/N-acetylaspartate (NAA), and as the presence of lactate and lipid metabolites in 23 cases. Results : As the malignancy grade of the glioma rises, so too did the MG Scale of FDG-PET and Tl index (PET MG Scale (A : Gr. 1; 2 cases, Gr. 2; 2 cases, AA : Gr. 1; 1 case, Gr. 2; 1 case, GB : Gr. 2; 2 cases, Gr. 3; 1 case), Tl index : A : 1.29±0.22, AA : 1.97±0.44, GB : 3.42±1.38). Metabolite ratios of Cho/Cr and Cho/NAA in the high-grade gliomas were higher than those in the low-grade gliomas, however, those of GB were lower than those of AA, maybe due to difficulty in the spectroscopic voxel selection (Cho/Cr : A : 1.86, AA : 2.96, GB : 2.73, Cho/NAA : A : 2.90, AA : 6.37, GB : 5.57). Both lactate and lipids presented in the high-grade glioma cases. Proliferative potential as measured by MIB-1 index mostly correlated with the Tl index significantly (p=0.0002). Conclusion : We were able to evaluate the malignancy grade of gliomas preoperatively by using FDG-PET, Tl-SPECT and MRS, however, we also need to understand the pitfalls of each of these examinations respectively.

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The bipolar forceps coagulation system has played an important role in advancing neurosurgery. Its precise and adequate coagulation under microscope has greatly progressed neurosurgical technique. However, several problems remain in coagulation with bipolar forceps because it is not easy to control the heat of the tips. In the present study, we report the values of a new bipolar coagulation system with heat pipe technology (IsoCool^<TM>). Laboratory and clinical examinations demonstrated that the instrument has high efficiency in not only non-sticking but also in control of coagulation area. These results support the premise that this new instrument can add innovation in modern microneurosurgery.

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A 72-year-old woman presented with sudden onset of consciousness disturbance. On admission she was in a semicomatose state (W.F.N.S grade V). A CT scan showed subarachnoid hemorrhage. Angiography revealed a persistent primitive trigeminal artery (PPTA) and three aneurysms. Two were at the basilar artery-PPTA junction and the other one at the rt. internal carotid artery, cavernous portion. The larger one was located distal to the smaller one and was 4mm in size with a bleb. Because of the poor neurological condition associated with neurogenic pulmonary edema, she underwent coil embolization to the distal aneurysm via PPTA on the post-SAH third day. After embolization, she received a shunt operation due to normal pressure hydrocephalus and was transferred to the local hospital for further rehabilitation. This may be the first treated case of a ruptured aneurysm associated with the basilar artery-PPTA junction.

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We present a successfully treated case of a solid and huge hemangioblastoma of the medulla oblongata. A 33-year-old male with severe headaches was admitted to our hospital. Preoperative MRI and cerebral angiogram demonstrated a solid well-circumscribed highly vascular tumor at the dorsal medulla oblongata. Presurgical embolization and total removal of the tumor were performed. Postoperatively, the patient developed hemiparesis and lower cranial nerve palsy. But his symptoms improved gradually and he returned to his former ordinary life 6 months later. A huge brainstem hemangioblastoma is rare and, its surgical treatment is frequently associated with high risk. We report the surgical strategy of this unusual case and practical perioperative management.

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The authors report a case of a 37-year-old man with recurrent of perimedullary arteriovenous fistulas (PMAVFs) located at the level of the conus medullais after embolization with N-butylcyanoacrylate (NBCA). The patient was treated 5 years ago in another hospital for two AVFs at separate sites including PMAVFs at the conus medullaris and a dural AVF at the sacral region by transcatheter embolization with NBCA. Complete obliteration of the PMAVFs at the conus medullaris was comfirmed by angiography. The dural AVF at the sacral region was treated successfully thereafter by surgery because of recanalization. However, he was admitted to our institution with a recurrence of low back pain and thoracic tightness. Neurological examination showed a spastic paraparesis, disturbance of superficial sensation below the L_4 dermatome on both sides and dysuria. Magnetic resonance images revealed an enlarged conus medullaris and many serpentine flow-void signals from the lower thoracic to the upper lumbar region. Recurrence of the AVFs at the conus medullaris was comfirmed by selective angiography. He was treated surgically with the assistance of intraoperative microvascular Doppler and spinal digital subtraction angiography (DSA). He made a good postoperative recovery with gradual improvement of his neurological symptoms. Both surgical and endovascular methods have a role in the management of PMAVFs. However, after a failed or partial embolization of a PMAVF, surgery should be considered so as to achieve complete obliteration. Intraoperative microvascular Doppler and spinal DSA are of valuable assistance in surgical closure of spinal AVFs. Close follow-up observation is also required even if complete obliteration is comfirmed by angiography.

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