The treatment of arteriovenous malformation (AVMs) depends on the efforts of a multidisciplinary team to provide better results than its natural course. Treatment options are reviewed based on our personal experience series of 208 grade III operated AVMs in a 10-year period. The Spetzler-Martin classification was modified to include subdivisions in the heterogeneous group of grade III AVMs as follows : IIIA(large cortical AVMs), IIIB(small limbic lobe AVMs) and IIIC(small insula lobe AVMs), to augment the surgical resection criteria. The treatment strategy was for most of the cases embolization plus surgery for grade IIIA, surgery for subdivision IIIB and radiosurgery for most and surgery for selected cases of IIIC. The surgical results (good outcome : IIIA 81%, IIIB 86% and IIIC 87%) showed that in spite of the higher surgical and anatomical complexity for the IIIC group in comparison with those IIIB and IIIA AVMs, there are selected cases that can be surgically approached with similar or even better surgical outcomes based on the subdivision proposed. Indeed, these data indicate that the treatment of AVMs can achieve better results when compared to its natural course if managed by a well-trained group of specialists led by an experienced neurosurgeon.

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Certain tumor suppressor genes play an important role in the proliferation and differentiation of neural stem cells and their alterations are directily involved in the tumorigenesis of pediatric brain tumors such as medulloblastoma. We summarized the up-dated molecular genetics of medulloblastoma with a special emphasis on the Wnt/APC and Shh/PTCH pathways.

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Cell cycle checkpoints prevent transition from one phase of the cell cycle to the next until all processes of the present phase are completed. Defects in the checkpoint functions result in gene mutations and chromosome damages, which contribute to the development and progression of tumors. However, loss of checkpoint function in some cancer cells is considered to be associated with their sensitivity to antineoplastic treatments such as chemotherapy and radiation therapy. Most cancer therapies target cell cycle checkpoints by activating checkpoint-mediated cell death or by enhancing chemical sensitivity due to loss of checkpoint function. By treatment with genotoxic agents, cancer cells, which generally have impairment of checkpoint functions, initially arrest in the G2 phase of the cell cycle but are unable to maintain cell-cycle arrest. Those cells eventually die as they entered mitosis. This process is called 'mitotic catastrophe'. This review discusses the critical relationship between mitotic checkpoint function and sensitivity of cancer cells to anti-tumor therapies.

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The purpose of the surgical treatment for traumatic spinal cord injury is to stabilize the spinal column and to avoid secondary cord damage. Recently, many modalities such as spinal instrumentation and navigation systems have been developed. They are quite useful in the surgical management of cervical injuries, facilitating early ambulation, short hospital stays and an early return to work and normal activities. It is important to have a precise diagnosis for proper decision-making and to know surgical techniques in the management of spinal cord injuries.

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Discography is a diagnostic tool to determine whether or not a particular patient should be fused for achieving pain relief. We have been conducting discography to identify the appropriate degenerative level to be fused in patients whose neuroimaging data did not show the exact location of the pain generating site. A satisfactory surgical result has been obtained with individuals treated by anterior lumbar interbody fusion, so far as these individuals presented positive provocative tests results by discography. The surgical procedure is a mini-ALIF arranged in order to realize a minimally invasive procedure. This procedure has been applied not only to patients with discopathy but spondylolisthesis and canal stenosis as well. The surgical results of these patient groups proved to be satisfactory. There are individuals whose pain generating site is localized even though their neuroimaging data indicates multiple diseased levels. In this situation, discography is the sole tool to identify the diseased level. Provided that the neuroimaging data discloses an unstable spine, PLIF supplemented by pedicle screw instrumentation will be recommended.

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The use of embolization for cerebral arteriovenous malformations (AVMs) as the pretreatment of surgical extirpation and radiosurgery has recently diminished due to the passive application to asymptomatic patients and growing preference for radiosurgery based on its superior results. However, the embolization still plays an important role in some difficult AVMs. It is particularly significant in terms of the following : (1) reduction of nidus size and shunt flow, (2) elimination of inappropriate factors so as to achieve the maximum effect of the secondary treatments, (3) treatment for associated aneurysms posing high risk of rupture. The basic concept of AVM embolization is not to pursue total AVM obstruction by embolization alone but to avoid rebleeding and deteriorations of symptoms by targeted embolization. To perform a safe and effective embolization, the following points are thought to be very important : (1) understanding the angioarchitecture of the functional brain using various functional imagings and provocative tests, (2) an embolization design and strategy proportionate to the secondary treatments, (3) nidus embolization with materials that pose the least risk of recanalization, and (4) assuring appropriate perioperative care based on the principles of risk management. In spite of taking such precautions the rate of compcliaions was 13.9%, and the morbid-mortality rate was 4.9% in our series. Two patients with an angiographic cure of temporooccipital AVMs suffered from extensive intracerebral bleeding 6 and 8 years after radiosurgery. Therefore, we should reconsider the multi-modality treatment strategy of AVM, including embolization, and reevaluate its efficacy based on the risk-benefit assessments.

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Ultra-early surgical treatments are expected to be established, in which the associated brain injury is minimized and a maximal volume of hematoma is removed shortly after onset with secure hemostasis. We developed a transparent guiding sheath and other surgical instruments for endoscopic surgery, and we established a novel surgical procedure in the ultra-early stage using those instruments. This procedure has the following characteristics : (1) the capability of burr hole opening under local anesthesia, (2) a transparent sheath improves the surgical field visualization of the parenchyma and the hematoma, (3) free-hand surgery without fixing an endoscope and a sheath to a frame facilitates three-dimensional operation, (4) the capability of secure hemostasis by electric coagulation (When bleeding from a perforating artery occurs, a suction tube is placed at the bleeding point and hemostasis is achieved by electric coagulation), (5) easy preparation of relatively simple surgical instruments. We have performed this procedure on 85 patients with intracerebral or intraventricular hemorrhage. Among these 85 patients, 24 patients received our treatment in the ultra-early stage, or within 3 hours after onset. The mean duration of surgery was 63 minutes, the mean hematoma reduction rate was 96%, and no perioperative hemorrhage with deterioration of symptoms and/or signs occurred. Thus, we believe that endoscopic hematoma evacuation with our surgical procedure is a promising ultra-early-stage treatment for intracerebral hemorrhage, and that it may improve the long-term prognosis of patents with intracerebral hemorrhage.

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Dissecting aneurysms involving only the posterior inferior cerebellar artery (PICA) and not the vertebral artery at all are rare. We report here snch a case of a 60-year-old male. He experienced sudden severe headache when working. One hour later he suffered from a rapid deterioration of consciousness disturbance. On emergency admission, he presented with deep coma. Computed tomography demonstrated a thick subarachnoid hemorrhage (Fisher group 3). Vertebral angiography revealed aneurysmal dilatation at the anterior medullary segment of the PICA, with distal narrowing (pearl and string sign). Moreover, the perforating artery to the brain stem originated from or very near the aneurysm itself. On day 1, the aneurysm was treated with endovascular occlusion of proximal the PICA with a Guglielmi detachable coil. The patient showed Wallenberg syndrome after treatment. Magnetic resonance imaging demonstrated an infarcted area in the left lateral portion of the medulla and left cerebellar hemisphere. But he recovered gradually and now he needs no assistance. Although there were many problems including ischemic complications when trying endovascular embolization for this lesion, we successfully prevented rerupture of the aneurysm on early period. The treatment of dissecting aneurysms of the proximal segment of the PICA with SAH is controversial. We review 27 cases of dissecting aneurysms of the PICA in this study.

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