Conventional surgical or endovascular treatments for giant cerebral aneurysms are reported to have low aneurysmal control rate and high morbidity. For such complex aneurysms, we applied a new strategy that reduces hemodynamic stress in the aneurysm by isolating several normal branches originating from the aneurysmal neck or dome with or without bypasses.
  This flow reduction strategy effectively promotes thrombosis and shrinkage of complex aneurysms for which we cannot apply conventional treatment methods. Although the flow reduction treatment seems promising, some problems became evident. Delayed perforator thrombosis is partially avoidable by detailed flow simulation, but is also a dilemma inherent in the flow reduction strategy itself. Gradual aneurysmal growth and hemorrhage after complete thrombosis is another difficult problem of unknown etiology. The basic concept of the strategy, countermeasures for problems and future outlooks for flow reduction treatment are reviewed.

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  Cerebral aneurysm embolization using Guglielmi detachable coils has been approved for reimbursement in Japan since 1997 ; however, it was still considered an alternative treatment modality for the difficult open surgery.
  Thereafter, the advantages of using the endovascular procedure for ruptured intracranial aneurysms were reported in ISAT in 2002 and as a result this procedure became a big topic in aneurysm treatment.
  In November 2011, the Barrow Ruptured Aneurysm Trial also reported on the advantages afforded by the procedure, and it was concluded that “high-quality surgical clipping be available as an alternative treatment modality.”
  Conversely, following the global trend towards endovascular aneurysm treatment, the craniotomy procedure has become an alternative treatment modality to be used only if conducting endovascular surgery is difficult.
  However, this indication status is only when dealing with general aneurysm treatment and there is no clear direction for difficult-to-treat cerebral aneurysms.
  Tailor-made treatment is needed ultimately, but I would like to consider a treatment strategy for difficult-to-treat cerebral aneurysms from the position of a certified endovascular treatment practitioner.
  There are still major issues remaining for wide neck aneurysms, giant aneurysms, aneurysms involving any arteries and partially thrombosed aneurysms. I would like to offer an overview of “the remaining issues in current neuroendovascular procedures” by presenting these cases.

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  Several issues remain to be solved in the treatment of subarachnoid hemorrhage (SAH), including the pathophysiology, treatment, and social impact. Over 20% of patients are not diagnosed on the day of onset of SAH, and the definitive criteria for vasospasm, an important and dangerous sequela of SAH, have not been standardized. Discussion of the selection of clipping or coil embolization treatment has converged, but the frequent perioperative complications encountered with both these modalities must be recognized. A nationwide study is required in Japan to assess the actual situation of SAH treatment, including outcome, complications, and socio-medical costs, to prevent the isolated development of medical approaches to SAH in Japan. SAH treatment in the future may face two different challenges, reduction of medical systems in rural districts and sharp increases in demand for medical facilities in the metropolitan area. The uneven distribution of board certified neurosurgeons in Japan might also pose considerable problems.

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  According to the result of UCAS Japan and recent literature, we summarized the findings on the natural course of unruptured cerebral aneurysms. Rupture risks are significantly related with the size, location and shape of the aneurysms. Also, in previous reports, patients with a history of hypertension, current smoking and subarachnoid hemorrhage were reported to carry a high rupture risk. Indication for managing unruptured cerebral aneurysms should be directed according to the patient's medical condition, natural course of the individual aneurysm and the probability of the management risk of the individual aneurysms in each institution. In general, aneurysms sized more than 5 to 7 mm in healthy patients, and, even smaller than that, aneurysms located at the anterior communicating and posterior communicating arteries, and irregular shaped aneurysms should be considered for treatment. But of note, small aneurysms can rupture even when smaller than 5mm under certain risk and aneurysm management carries a morbidity risk. These issues should be well explained to the patients. Regarding growth of aneurysms, there are a few reports documenting aneurysm growth in small aneurysms, and, if the aneurysm is not treated, careful follow-up is mandatory even in cases with small aneurysms.

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  Pathological investigations have revealed degenerative changes in the vascular walls of intracranial aneurysms (IA) that lead to their rupture. Results from studies using an experimentally induced IA model have provided us a wide variety of evidence supporting the notion that IA is closely associated with inflammation. The inflammatory cascade begins with the activation of nuclear factor-kappa B (NF-κB) in endothelial cells, which up-regulates the expression of monocyte chemotactic protein-1 (MCP-1) recruiting macrophages into IA walls. Macrophages secrete matrix metalloproteinases (MMPs) -2 and -9 that promote the degradation of IA walls. It has also been demonstrated that treatment with statins and decoy oligodeoxynucleotides against NF-κB and Ets-1 suppresses the development of rat IAs by inhibiting inflammatory reactions. On the other hand, computational fluid dynamics (CFD) has been recently applied to the analysis of flow patterns in IAs. The next issue to be solved is the identification of the linkage between flow patterns in IA and inflammatory responses in IA walls. Solving this issue will enable us to predict the probability of IA rupture and to prevent unruptured IAs from rupturing.

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  It is practically important to identify and monitor the eloquent brain functions for maximal resection of brain tumors. Although electrocortical stimulation (ECS) with awake craniotomy or implanted subdural electrodes is the gold-standard for brain mapping, it always contains the risks of seizure and pain. Recent studies reported that the electrocorticogram (ECoG) might have great potential to identify language centers by emphasizing high frequency oscillations. We performed detailed functional mapping using ECS and ECoG for a patient with a brain tumor located near the language-related area. We focused on the high frequency components of ECoG between 60 and 120 Hz, the high Gamma activity (HGA) range. HGA induced by a word-reading task appeared around 600 msec after stimulus onset in the posterior language area, which was confirmed by ECS. In addition, HGA clearly delineated functional dynamics related to the reading task from the occipital to the frontal and temporal regions. We believe that ECoG mapping could become an alternative to ECS mapping and awake craniotomy.

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  We report a case of successful detection of bioelectric potential from the paretic leg muscles during acute stage of rehabilitation using a Hybrid Assistive Limb (HAL). A 56-year-old woman suffered a left severe hemiparesis after the clipping surgery of a ruptured aneurysm. Bed side rehabilitation was conducted from postoperative day 2 and rehabilitation using HAL from postoperative day 7. Initially no voluntary movement was observed in the left paretic leg muscle while minimal bioelectric potential was detected from the rectus femoris muscle, vastus lateralis muscle, and biceps femoris muscle when she was standing with the assistance of HAL. On postoperative day 9, bioelectric potential was detected from all monitored muscles during voluntary extension of the non-affected leg. Voluntary movement of the affected leg was then observed together with an increase in selective and phasic bioelectric potential. On postoperative day 22, the patient was able to walk without using HAL. Contralateral leg movement may facilitate selective and phasic muscle activities during acute stage rehabilitation after a stroke. HAL could assist the paretic leg by preventing falls and could provide feedback to patients relating to their walking posture, facilitating acute phase rehabilitation.

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