Object: The purpose of this retrospective study is to evaluate the effectiveness of gamma knife radiosurgery (GKS) alone for metastatic brain tumors from lung cancer. Materials and Methods: Two hundred thirty-one consecutive patients with metastatic brain tumors from lung cancer filling the following 4 criteria were analyzed for this study; 1) no prior brain tumor treatment, 2)25 or fewer lesions, 3) a maximum 5 tumors with diameter of 2 cm or more, 4) no surgically inaccessible tumor 3 cm or greater in diameter. According to the same treatment protocol, large tumors (≧3 cm) were surgically removed and all the other small lesions (<3 cm) were treated with GKS. New lesions were treated with repeated GKS. The tumor-progression-free, overall, neurological, lowered-QOL (quality of life) -free and new-lesion-free survivals were calculated with the Kaplan-Meier method. The poor prognostic factors for each survival were also analyzed with the Cox's proportional hazard model. Results: The tumor control rate at 1 year was 96.5%. The estimated median overall survival time was 7.7 months. The first-year survival rates were 83.0% in neurological survival and 76.0% in lowered-QOL-free survival. The new-lesion-free survival at 1 year was 27.9%. Multivariate analysis revealed significant poor prognostic factors for neurological and lowered-QOL-free survivals were carcinomatous meningitis and >10 brain lesions. Conclusions: This study suggests the results of GKS for metastatic brain tumors from lung cancer are quite satisfactory considering prevention of neurological death and maintenance of QOL. But cases with carcinomatous meningitis and/or >10 brain lesions are not good candidates for GKS alone.

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Twenty-six cases of astrocytic tumors were studied with positron emission tomography (PET). All cases were subjected to the fluorodeoxyglucose-PET and some of them were studied with methionine-PET as well. The accumulation of isotope was semi-quantitatively analyzed using the following criteria: grade 1: less than normal white matter, grade 2: same as normal white matter, grade 3: between normal white and gray matter, grade 4: same as normal gray matter, grade 5 more than normal gray matter. For FDG-PET, the average value of grades for glioblastoma, anaplastic astrocytoma and astrocytoma (grade 2) were 4.6, 3.9 and 2.5, respectively. Thus, FDG accumulated more in higher grade tumors. On the contrary, the methionine accumulation was observed even in astrocytoma and useful in identifying less malignant tumors. However methionine was accumulated on areas of radiation induced brain damage. In conclusion, methionine-PET was sensitive but less specific in identifying astrocytic tumors whereas FDG-PET is useful in determining the extent of malignancy.

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Carotid endarterectomy is one of the evidence based surgery supported by multiple randomized clinical trials. However, its indication should be limited to surgery to be performed by the approved surgeons who has standard surgical techniques and anatomical knowledge and most of all, know how of risk management. In this paper, the following aspects of the carotid endoarterectomy are reviewed for the beginners and less experienced neurosurgeons 1) Preoperative examination and key points 2) Surgical anatomy for accurate and fast exposure of the carotid artery including surface anatomy and anatomy of important nerves and vessels. 3) Standard techniques for routine carotid endarterectomy 4) Analysis of the causes of risk and the remedies for management of these risks.

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Two operative cases of symptomatic sacral perineural cyst were reported with some review of the pertinent literature. Case 1 was a 41-year-old female who had been suffering from sharp pain in her bilateral S2 territory for 3 months. An MR study revealed bilateral sacral perineural cysts at the S2 level. She was treated by partial resection and closure of the cyst wall following a total laminectomy from L5 to S4. Case 2 was a 38-year-old female with a 4-month history of pain and dullness in the left S2 territory and frequent urination. An MR study disclosed a sacral perineural cyst at the left S2 level. She was treated by bipolar cautery of the cyst wall following the hemilaminectomy of S2, under an electrophysiological monitoring. The symptoms and signs were improved in both cases, though the case 1 required another operation to close the CSF fistula. Comparing surgical results of our cases, the authors concluded that 1) it seems safer to cauterize the cyst wall under the electrophysiological monitoring than to resect it, and 2) a hemilaminectomy around the referred nerve root seems sufficient for treating sacral perineural cysts.

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An aneurysm of the distal anterior inferior cerebellar artery (AICA) is extremely rare. The authors report the case of the ruptured AICA-internal auditory artery (IAA) junction aneurysm, and review the literatures, with a focus on the surgical strategies for treating this aneurysm. A 72-year-old woman presented with sudden onset of severe headache and hearing disturbance. Computed tomography revealed a subarachnoid hemorrhage and magnetic resonance imaging (a heavily T2-weighted image) revealed that the dome of the aneurysm was in the right internal auditory meatus. Cerebral angiography revealed a saccular aneurysm at the meatal loop of the right AICA. An emergency operation was performed through the right suboccipital approach. We confirmed that a 5 mm aneurysm had formed, and that it was located between the facial and acoustic nerves. At the sacrifice of the acoustic nerve and IAA, the aneurysm was completely clipped using 2 Sugita's clips. The distal circulation of the AICA was preserved. In the literature, most cases of ruptured AICA-IAA aneurysms present with facial or/and acoustic nerve deficits. When performing surgery for these types of aneurysms, it is difficult to preserve the acoustic nerve and to recover functional hearing. Therefore, surgeons should give priority to managing the ruptured aneurysm, and to preserving the facial nerves.

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Interhemispheric subdural hematomas are a relatively uncommon type of subdural hematoma. A surgical case of acute interhemispheric subdural hematoma following head trauma with a widespreaded convexity subdural hematoma was reported. The patient was a 75-year-old female, who was hit in her occipital region. At the time of admission, she was in a semicomatose state and this was noted as associated with anisocoria. CT scans showed a thick convexity subdural hematoma and an thin interhemispheric subdural hematoma on the left side. Immediately after admission, surgery was performed for the left convexity subdural hematoma. Postoperative CT scans demonstrated an unexpected increase of the left interhemispheric subdural hematoma. And also, her consciousness disturbances (JCS 30) and right hemiparesis remained left. We decided to perform surgery for the left interhemispheric subdural hematoma. Left small frontal craniotomy was performed. In the surgery, a micro laceration of the cortical artery was confirmed as the bleeding point. Her symptoms improved postoperatively. This is the first report representing the interesting mechanism of a micro laceration of the cortical artery. We concluded that surgical management should be considered to confirm the bleeding point in these cases where severe symptoms are continuously present.

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We report a case of vertebrobasilar insufficiency caused by cervical spondylosis at C5/6 on head rotation to the left. A 41-year-old man who had congenital C2/3 fusion, and underwent C6/7 anterior fusion after disc herniation developed vertebrobasilar insufficiency that occurred when he rotated his head to the left. Cervical spine X-ray revealed C4/5 instability and spondylotic change at C5/6 on the left. MRI showed lateral displacement of the vertebral artery due to osteophyte formation and a protruded disc; displacement of this artery increased markedly with head rotation to the left. Vertebral angiogram showed tortuosity and stenotic change at the C5/6 level, and the stenosis increased to slow the blood flow upon head rotation to the left. We performed anterior fusion with autograft after resection of the osteophyte and herniated disc on the left, and the patient's ischemic epiosodes disappeared. We discuss the mechanics of injury leading to the stroke and the treatment modality.

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We experienced a case of deep vein thrombosis (DVT), pulmonary embolism (PE), and nonocciusive mesenteric ischemia (NOMI) after the removal of recurrent craniopharyngioma. A 58-year-old man, who had received surgery for craniopharyngioma 2 times, was admitted to our hospital because of bitemporal hemianopsia and recent memory disturbance. CT and MRI showed the recurrence of craniopharyngioma. After surgical removal of the tumor, the patient showed polyuria and dehydration caused by cerebral salt wasting syndrome and/or diabetes insipidus. Because of uncontrollable dehydration, the patient suffered from DVT/PE and NOMI. The patient recovered completely with early diagnosis and appropriate treatment. The mortality rates of DVT/PE and NOMI increase when diagnosis and treatment are delayed. We should take care for the patients with dehydration, which is one of the risk factors of DVT and NOMI.

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