To investigate medical publication trends in Japan, the databases of scientific papers released by Thomson Reuters and by the U. S. National Library of Medicine (PubMed) were analyzed. The number of papers published from Japan in clinical medicine and basic medical fields showed stagnant or declining trends after around 2000. In comparison, the numbers of other major countries showed rising trends. The worldwide share of medical publications from Japan declined sharply. The relative impacts or Japanese medical scientific papers have remained lower than the world average, but those of major countries are rising. The trends for the medical publications of universities in regional areas showed the largest decline. A decrease in the number of researchers and research time at universities who have difficulty dealing with outside factors, such as corporation with national universities. governmental budget cuts. and the fluidization of young medical doctors caused by the introduction of a new residency matching system, might be a causing factor.

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In Japan, the number of students who study abroad has declined recently, and the same phenomenon was confirmed in 80 Japanese neurosurgical departments in a survey which was conducted from March to August 2010. The number of neurosurgeons who studied abroad decreased by half from 2000 to 2010, and the decrease was particularly prominent in the field of basic research. A tendency amongst young neurosurgeons to perform clinical activity and learn surgical skills has accelerated after the introduction of a new postgraduate clinical training system. but a well developed scientific point of view including neuroscience and vascular science are essential for the establishment of neurosurgery as an independent scientific field. Studying abroad in the field of basic research requires enthusiasm and a willingness to execute research, but it can provide us with perspective as to international standpoints and help foster a scientifically logical way of thinking.

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In this article, the author discusses the significance of basic and/or clinical research on the career of Japanese neurosurgeons by reviewing his 25-year experience in Japan and Sweden. We should always aim to improve social welfare by developing our neurosurgical skills day by day so that we may better serve our patients. The author believes that we have to acquire scientific (or logical) thinking through basic and or clinical research for tins purpose.

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All of the knowledge, examination procedures and therapies that we use in routine clinical situations are based on the results of the basic and clinical studies undertaken by senior investigators. If a clinician does not undertake clinical study. their ability to practice may be negatively impacted. Therefore. the significance and practice of clinical research for young neurosurgeons is discussed in this paper. Even if cases are comprised of common diseases, they always have their own individual characteristics that make them unique. In other words, all cases deserve to be published as case reports. Young neurosurgeons should be conscious of this fact and should develop the skill to see the unique characteristics of each case. Then, they can find some thing unique in routine clinical situations on which to perform a case control or cohort study.

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Symptomatic radiation necrosis is a serious problem after high-dose irradiation for brain tumors. We studied the pathogenesis of radiation necrosis in 18 surgically excised specimens obtained at Osaka Medical College by Hematoxylin and Eosin (H&E) staining and immunohistochemistry. H&E staining showed marked angiogenesis, telangiectasia at the boundary between the necrotic core and normal brain tissue, the so-called peri-necrotic area. Reactive astrocytosis at the peri-necrotic area produced Vascular Endothelial Growth Factor (VEGF) abundantly. These findings are irrespective of original tumor types and radiation modalities. Therefore, we demonstrated the crucial role of VEGF in the pathogenesis of radiation necrosis. Thereafter, we reported the potent effects of bevacizumab, an anti-VEGF antibody, for the treatment of symptomatic radiation necrosis. In a single-institute clinical trial, we applied intravenous administration of bevacizumab to 12 consecutive cases of symptomatic radiation necrosis in the brain. All cases responded well to this treatment, with marked shrinkage of peri-lesional edema. These treatments were effective irrespective of the original tumor types and radiation modalities. Based on these observations, we applied for an Investigational Medical Care System Grant from the Ministry of Health, Labor, and Welfare (MHLW) to study "Intravenous administration of bevacizumab for the treatment of symptomatic radiation necrosis in the brain with the diagnosis based on amino acid PET". MHLW approved the grant on April 1, 2011, and the clinical trial is ongoing. Five institutes are now included in the study, and other several institutes will join it this year for a nationwide multi-institutional clinical trial. The final goal of this clinical trial is to determine the on-label use of bevacizumab for the treatment of symptomatic radiation necrosis in the brain.

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Object: In order to predict the technical difficulties of coil embolization for paraclinoid aneurysms (PC-an), we retrospectively analized our clinical experience. Method: We analyzed 34 patients with 35 PC-an treated with endovascular techniques between 2001 and 2010. These aneurysms were classified into 4 groups on the basis of their projections visualized on angiograms as follows: ventral, 17 ; medial, 7 ; dorsal, 8 and lateral, 3. The size of the aneurysms and the angle of carotid siphon were measured on angiograms for each group. The levels of those aneurysm necks were classified as supraclinoid, clinoid and infraclinoid according to their relation to the anterior clinoid process. Angiographic outcome, volume embolization ratio (VER), number of microcatheters and microguidewires used and duration of endovascular procedure were evaluated for each group. Clinical outcomes were assessed using the Glasgow Outcome Scale (GOS). Result: The mean size of the aneurysms in the ventral, medial, dorsal and lateral groups was 4.1, 5.6, 6.7 and 8.4 mm, respectively. The mean angle of carotid siphon was more acute in the dorsal and lateral groups. The neck level was supraclinoid in 10, clinoid in 14 and infraclinoid in 11. The percentage of dorsal and lateral groups was larger in the supraclinoid level. Endovascular treatment was successfully performed in 91.4% cases with treatment complications including 3 ischemic events. The number of patients with clinical outcomes classified according to the GOS was as follows: good recovery, 31 ; moderately disabled, 2 ; severely disabled, 1 ; vegetative state, 0 and dead, 1. Complete obliteration was achieved in 70.6%, 57.1%, 32.5% and 0% patients in the ventral, medial, dorsal and lateral groups, respectively, and the corresponding VER was 37.6%, 32.3%, 24.8% and 16.4%. The number of microcatheters and microguidewires used was higher in the dorsal and lateral groups than that used in the other 2 groups. The duration of the procedures was also longer in the dorsal and lateral groups. Conclusion: Endovascular treatment is a safe and effective therapeutic alternative for PC-an. However, in dorsal and lateral PC-an, this treatment entails additional difficulties of handling microcatheters and microguidewires because of their anatomical specificity. Therefore, endovascular treatment for these aneurysms is occasionally associated with lower rates of complete obliteration and lower VER than those of ventral and medial PC-an.

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We herein report a case of progressing stroke treated with a "hemi-bonnet bypass" A3-RA graft-STA anastomosis. An 86-year-old female suffered sudden onset right hemiparesis, and was diagnosed with a cerebral infarction. CT angiography at 24 hours after symptom onset revealed a left common carotid artery obstruction. A CT perfusion study revealed reduction of the cerebral blood flow in the territory of the bilateral anterior cerebral arteries and left middle cerebral artery. At 48 hours after symptom onset, her neurological status deteriorated to NIHSS 19 with akinetic mutism from 2. A diffusion MRI study revealed no marked changes in the spotty infarctions in the watershed region of the left anterior and middle cerebral arteries. We therefore performed a "hemi-bonnet bypass", left A3-right radial artery graft-right superficial temporal artery anastomosis. Her neurological status improved to NIHSS 5 on post-operative day 1. She underwent rehabilitation, and was discharged with NIHSS 2 and mRS 2. The "hemi-bonnet bypass" requires a short distance of graft vessel (allowing for the possible use of the radial artery), and does not need a position change during the operation. However, the cerebral blood flow from the ACA-A3 to MCA and contralateral A2 depend on the development of ipsilateral ACA-A1 and an anterior communicating artery. Therefore, if the ACA-A3 is selected as the recipient vessel, careful observation of the circle of Willis is essential.

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We describe a rare case of intraventricular hemangiopericytoma. The patient was a 78-year-old right-handed woman who presented with consciousness disturbance caused by an intraventricular hemorrhage. The tumor was in the trigone of the lateral ventricle with strong peritumoral edema. The tumor's maximum size was 60 mm. Preoperative angiography showed rich vascularity in the tumor. It was considered that her symptoms, consisting of left unilateral spatial neglect and left hemianopsia, could not be recovered. Thus, we selected a trans-angular gyrus approach to obtain a wide operative field to reduce intraoperative hemorrhage. The tumor was removed totally and the intraoperative hemorrhage was limited to only 420 ml.

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