1) Results of chemotherapy for malignant gliomas. The randomized clinical trial BTSG 75-01 and recent meta-analysis of chemotherapy for malignant gliomas from 12 randomized trials showed that radiotherapy and chemotherapy with nitrosoureas offered a significant prolongation of survival over radiotherapy alone. Interferon α and β do not appear to prolong the progression-free period and overall survival of patients with malignant gliomas. 2) Drug resistance to nitrosoureas and methods for overcoming this resistance. It was shown that the MGMT level in tumor cells correlates with the survival of patients with malignant gliomas who were treated with nitrosoureas. Depletion of MGMT before administering nitrosoureas is the method for overcoming nitrosoureas resistance. 3) Prediction of drug sensitivity. The MGMT level in tumor cells seems to be a predictive factor for patients with malignant gliomas who are treated with nitrosoureas and temozolomide. 4) New drug. Temozolomide is the most promising new drug and a phase III study of concomitant radiotherapy plus temozolomide for newly diagnosed glioblastoma showed a survival benefit over radiotherapy alone. Mechanisms of resistance to temozolomide are the MGMT level in the tumor cells, deficiency of the mismatch repair system and base excision repair, and DNA base excision repair seems to be a useful therapeutic target in mismatch repair system-deficient cells. 5) Molecular targeting therapy. A correlation between EGFR and survival of patients with glioblastoma was shown and EGFR is a reasonable molecular therapeutic target.

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Subjects and Methods : The subjects were 177 patients with asymptomatic leukoaraiosis (AL) among 2,160 persons who received a complete medical checkup of the brain. The subjects were examined for (1) the detection rate and characteristics according to age, (2) risk-factor complication rate, (3) fibrino-coagulation examinations, (4) ventricular measurements, (5) higher cerebral function examinations, (6) cerebral blood flow measurements (CBF), an increasing rate (IR) on the glycerol tolerance test (GTT), (7) the serum α-1-antichymotrypsin value (α-1-ACT), and (8) the cerebral arterio-venous difference of oxygen content value (c-AVDO_2). The results of (2)-(8) were compared with those of 50 persons of a control group without intracranial lesions. Results and conclusions : (1) AL was found in 8.2% of persons who received a complete medical checkup of the brain, with the mean age being significantly high and the detection rate inceresing with age. (2) The risk factors included hypertension, hyper-lipidemia, asymptomatic cerebral infarction on MRI, and cerebral arteriosclerosis on MRA. (3) The blood viscosity, coagulation and fibrinolysis functions increased and the platelet functions were maintained. (4) No significant difference with the control group was found in the ventricular and higher cerebral function examinations. (5) The CBF decreased, as well as the vascular reserve ability (decreased IR) in GTT. (6) From the fact that an increased α-1-ACT was absent and the c-AVDO_2 increased significantly, the pathologic condition of AL is considered "a compensated reduction of the cerebral blood flow resulting from cerebral ischemia accompanying an increase in the blood viscosity, coagulation and fibrinolysis functions, in which there is underlying cerebral arteriosclerosis."

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Pilocytic astrocytomas generally occur in children and they are morphologically circumscribed and often cystic. In contrast, those in adults predominantly occur in the supratentorial area, are less common. The case presented here is pilocytic astrocytoma of the cerebellar vermis in a 26-year-old woman and is characterized by an infiltration to the surrounding parenchyma without macroscopic cysts. We could not gross-totally resect the tumor due to the ill-defined demarcation between the tumor and the surrounding brain. Histological studies of the tumor specimen demonstrated a pilocytic astrocytoma. The patient subsequently received localized radiation therapy with 50 Gy and has been well, without tumor recurrence, for six years since the surgery.

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A 68-year-old man who developed subarachnoid hemorrhage (SAH) during irrigation for the treatment of chronic subdural hematoma is reported. The cause of this rare complication was presumed to be tearing of small vessels in the subarachnoid space by evacuation of the subudural hematoma associated with rupture of the hematoma membrane resulting from inadequate insertion of the irrigation catheter. This case indicates that subarachnoid hemorrhage during evacuation of a hematoma by burr-hole irrigation with a catheter must be listed as a complication of evacuating surgery for chronic subdural hematoma. Care must be taken to prevent SAH during the surgery, with careful insertion of the catheter to avoid rupturing the inner membrane of the hematoma and care must also be taken to avoid sudden evacuation of the hematoma that may induce a pressure difference or distortion between the supra and infra tentorial fossa, especially in patients suffering from hypertension, arteriosclerosis, unruptured aneurysm and advanced age.

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We report two cases of ruptured lateral paraclinoid carotid aneurysms. Case 1 : A 41-year-old man presented with a sudden headache. A CT scan showed a subarachnoid hemorrhage. Cerebral angiography revealed a large paraclinoid carotid aneurysm projecting posterolaterally. Proximal artery control was accomplished through a balloon catheter prior to craniotomy. The aneurysmal neck was not broad, so the clip was placed perpendicularly to the carotid artery. Case 2 : A 71-year-old woman presented suffering from a headache and simultaneous double vision. A CT scan showed no apparent subarachnoid hemorrhage. Cerebral angiography revealed a large paraclinoid carotid aneurysm posterolaterally. Proximal artery control was accomplished by exposure of the cervical internal carotid artery prior to craniotomy. Intraoperative findings revealed a subarachnoid hemorrhage in the basal cistern. The aneurysmal neck was broad, so the clip was placed parallel to the carotid artery so as not to involve the posterior communicating artery. Paraclinoid carotid aneurysms of the ophthalmic segment are usually classified into three categories, but in the case of lateral projection, it is hard to definitively classify. This report describes such surgical experiences clipping ruptured lateral paraclinoid carotid aneurysms.

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A case of neurofibromatosis type-1 (NF-1) accompanied by vertebral arteriovenous fistula is presented. A 24-year-old-woman was admitted to our hospital with Brown-Sequard syndrome. Cervical MR image revealed a large abnormal flow void which occupied the left half of the spinal canal. An angiogram demonstrated a fusiform-type aneurysm and a high flow arteriovenous fistula in the left vertebral artery at C_<4-5>, draining into the internal vertebral plexus and forming a large venous varix there. Idiopathic vertebral arteriovenous fistula most frequently appear at C_<1-2>, and C_<5-6>. The mechanism of the rare arteriovenous fistula formation at C_<4-5> in this case was speculated as follows : a fusiform aneurysm at the vertebral artery (C_<4-5>) was initially formed due to mechanical stress, in the predisposing condition of NF-1 and cervical vertebral malfomation, and the arteriovenous fistula developed subsequently after its rupture. The arteriovenous fistula was successfully treated by endovascular obliteration including the aneurysm using detachable platinum coils.

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A rare case of cervical intradural lipoma is reported. Spinal cord lipoma without spina bifida is a benign tumor, which accounts for about 1% of all spinal neoplasms. When symptoms develop with slow growth, the purpose of medical treatment is neurological improvement. The operative approach to spinal cord lipoma is direct and the same as for any intramedullary process. We performed cervical laminoplasty over the length of the lesion and substantial debulking of the lipoma under SEP monitoring. Intraoperative recording of SEP was useful for surgical decompression during the operative procedure. We preserved a vein in the lipoma connected with the dorsal spinal vein and radiculomedullary vein. Damaging the spinal vein might cause neuropathy by venous congestion and edema of the spinal cord. Magnetic resonance imaging was useful for delimitating the anatomy of the lipoma in planning the operation.

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A case of a migrated lumber disc hernia composed of hyaline cartilage was reported with a brief review of migrated discs. A 73-year-old male was admitted to our department complaining of neuralgia and a tingling sensation in the left leg for three months. MRI depicted an extradural lesion mass with circumferential enhancement that compressed the left L_2 root. A herniotomy was performed and the symptoms disappeared a few days after the surgery. Pathological findings revealed that the migrated disc was entirely composed of degenerated hyaline cartilage with a very small amount of neovascularization and infiltrated inflammatory cells. This may lead to failure in the spanteneous reduction of the herniated mass. Cases with spontaneous absorption and disappearance of migrated lumbar disc were well known, however, surgical removal of the disc may be necessary in certain cases with persistent symptoms owing to root compression by the hyaline cartilage.

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