Atherosclerotic intracranial stenosis is a common etiology for ischemic stroke and TIA in Japan. The natural history of intracranial stenosis is poorer than that of patients with extracranial stenosis, with annual stroke rates that approximate 5% to 15%. There are no conclusive answers about the best medical treatment of intracranial stenosis. Retrospective data suggest that long-term anticoagulation with warfarin is more effective than antiplatelet therapy. However, recent data of a randomized prospective study suggest that aspirin rather than warfarin should be used to treat intracranial stenosis, because warfarin was associated with significantly higher rates of adverse events and provided no benefit over aspirin. Patients with symptomatic intracranial stenosis who fail antithrombotic therapy appear to have a high incldence of subsequent cerebral ischemic events. The optimal treatment strategy for patients with this disease remains undetermined.
Intracranial balloon angioplasty and stenting has recently been proposed as a promising treatment for patients with ongoing cerebral ischemic events despite standard medical therapy. The success rates of angioplasty alone and stent-assisted angioplasty have been reported to be approximately 85% and 95%, respectively. The complication rates of these procedures have been reported to be approximately 15%. Despite the recent advances in technology and experience, there are potential technical problems with the procedure, including dissection, vessel rupture, acute closure, elastic recoil, perforator occlusion, distal embolism, in-stent thrombosis, and hemorrhage due to hyperperfusion.
Currently the efficacy of endovascular therapy versus medical therapy for patients with symptomatic intracranial stenosis has not been compared in a randomized prospective trial. Therefore, for symptomatic patients with a severe intracranial stenosis who have failed medical therapy, balloon angioplasty with or without stenting should be considered. Patients who have an asymptomatic intracranial arterial stenosis should first be counseled regarding optimizing medical therapy.
There is insufficient evidence to make definitive recommendations regarding endovascular therapy in asymptomatic patients with severe intracranial atherosclerosis.

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Clipping an aneurysmal neck is considered an optimal treatment modality for ruptured and unruptured cerebral aneurysms. However, various anatomical variations in the relationships of parent artery, branched arteries, shape of the aneurysmal dome and aneurysmal neck frequently make it difficult to apply a simple clipping method using a single clip. To achieve safe and effective neck clipping, we use several techniques such as the clipping on wrapping method (COW method), tentative parallel clipping method (TPC method) and combination clipping with fenestrated clips (CCFC method). In this study, we analyzed the safety and effectiveness of these methods. In 515 surgeries for cerebral aneurysm performed between January 2001 and December 2003, the COW method, TPC method and CCFC method were used in 61 cases, 11 cases and 26 cases, respectively. In patients treated by the COW method, slight stenosis of the parent arteries was found on long-term follow-up studies in only 2 patients. In patients treated by the TPC method and/or CCFC method, complete obliteration of the aneurysm and preservation of blood flow through the parent arteries and branched arteries were confirmed.
These 3 techniques are safe and effective methods for aneurysmal neck clipping.

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Early outcome research in the neurosurgical literature on morbidity and mortality is now focusing on subjective or patient-based outcomes for assessing neurosurgical diseases and their treatment. The assessment of health-related QOL and its components based on the patient's health status is increasingly common in neurosurgical and other specialties. The popular Short Form-36 (SF-36) is a 36-item, patient-completed questionnaire that measures patient health-related QOL in each of 8 areas: physical functioning (PF), social functioning (SF), role-physical (RP), role-emotional (RE), mental health (MH), vitality (VT), bodily pain (BP), and general health perception (GH). Several outcome researches for patients who experienced subarachnoid hemorrhage concluded that SF-36 could detect mild disorders of cognitive or psychological function. QOL is also an important outcome measure for patients with unruptured intracranial aneurysms because these patients are usually in good health after treatment.
We assessed QOL in 61 patients who underwent microsurgical clipping of unruptured aneurysms. Preoperatively, patients with unruptured aneurysms reported significantly decreased QOL. It further declined transiently after elective surgery, but within 3 years it returned to the mean level recorded for the reference population. In obtaining patient's informed consent, data on QOL like the above help patients who are debating whether to undergo treatment for unruptured aneurysms. Subjective QOL issues should be considered in the management of patients with other neurosurgical diseases.
Comprehensive outcome research using several graded scales will be necessary for evaluation of patient's perception of health as well as neurological impairments and disability.

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We evaluated predictive factors for prolonged hypotension after carotid artery stenting by retrospectively analyzing 88 lesions of 77 consecutive patients (mean age: 69.9±8.0 years). Easy Wall stent was applied in 14 lesions, SMART stent in 35, Protégé stent in 15, Aurora stent in 11 and Precise stent in 13. We investigated correlations between the incidence of prolonged (≧3 hours) hypotension below 90 mmHg and clinical characteristics, angiographic findings and kind of deployed stents. Postprocedural hypotension occurred in 44 lesions (50%), and medical treatment (intravenous administration of catecholamines) was required in 21 lesions (23.9%). Although there was no permanent neurological deficits related with postprocedural hypotension, transient neurological deficits including consciousness disturbance were found in 5 patients. Predictive factors of prolonged hypotension were assessed by univariate and multivariate analyses. Among angiographic characteristics, calcifications at the carotid bifurcation (present vs. absent: p=0.004) were statistically significant on multivariate analysis. Although other variables including age, gender, side of lesion and degree of stenosis were not associated with postprocedural hypotension after carotid stenting, SMART (eR) stent and Protégé stent were accompanied with frequent occurrence of prolonged hypotension in this study.
Among angiographic variables, the presence of calcification at the carotid bifurcation can be used to identify patients at risk for postprocedural hypotension after carotid stenting. Furthermore, such identification may help us prevent a perioperative complication of CAS for high-risk patients.

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Treatment of unclippable posterior cerebral artery (PCA) aneurysms frequently requires revascularization of the PCA, especially in cases with poor collateral circulation flow. We report on the microsurgical revascularization of the PCA territories in 3 patients having PCA aneurysms. Case 1 involved a P2 partially thrombosed large aneurysm. The patient did not tolerate temporary balloon occlusion of the PCA. Case 2 had a P2 thrombosed fusiform aneurysm. Case 3 presented a P1/2 thrombosed giant aneurysm. A balloon occlusion test (BOT) was not used in Case 2 or 3. All patients underwent direct operation with revascularization: STA-PCA bypass and trapping of the aneurysms via combined approach, with favorable outcome. We discuss these operative approaches and procedures for microsurgical revascularization.

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Treatment of cerebral hemorrhage in the elderly is often difficult and a growing concern due to Japan's aging population. We retrospectively evaluated radiological images of intracerebral hemorrhages associated with cerebral amyloid angiopathy (CAA) and surgical efficacy for performance status of patients. From January 2000 to December 2005, 240 patients with intracerebral hemorrhage and 49 patients with cerebral subcortical hemorrhage were reported. Of these, 41 cases fulfilled the Boston criteria for CAA. Diagnosis by autopsy was 0, surgical biopsy histopathology 9, multiple hemorrhagic lesions 8 and single lesion in 24 patients. Involved lobes were frontal: 6, temporal: 1, fronto-parietal: 3, temporo-parietal: 8, parietal: 12, parieto-occipital: 6 and occipital: 5. CAA-related subcortical hemorrhages were commonly distributed in 2 lobes, with the parietal lobe the most commonly affected area. Radiological characteristics of CAA-related subcortical hemorrhages were irregular borders: 30/41 (73%) intraventricular ruptures: 15/41 (37%), and subarachnoid hemorrhage and/or acute subdural hematoma: 37/41 (90%).
Surgery was indicated if consciousness level (Japan Coma Scale) was greater than II-20 and hematoma volume greater than 40 ml. Craniotomy was performed on 18 patients with modified Rankin Scale (mRS) with 60% improving postoperatively and the remainder maintaining the same mRS as before surgery. Two patients underwent emergency craniotomy due to a rapidly growing hematoma producing a comatose state. Of the 18 surgical cases, 1 had further bleeding in a different area postoperatively at 3 months. Of the 23 nonsurgical cases, 4 had further bleeding after conservative treatment at 1.5 to 3.5 months with 1 case affected on 3 separate occasions.
Surgical removal of hematomas caused by CAA is safe and unlikely to accelerate the rate of further bleeding, but rather contribute to improvement of mRS in selected patients.

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Several advanced multiple catheter techniques have been invented for endovascular treatment. Stent-supported coil embolization is one of the most useful methods for wide neck aneurysms. We report 13 vertebral artery aneurysms treated with this method and discuss its efficacy.
Between April 1999 and March 2006, we treated 13 patients with wide neck vertebral aneurysms, comprising 9 males and 4 females aged 38 to 79 (mean 60.0 years old) and treated with stent-supported coil embolization. Stent for coronary intervention was used in all cases. Using our original method, the microcatheter was inserted into the aneurysmal sac in advance, followed by deployment of the stent at the orifice. In this method, the microcatheter is placed out of the stent, which is useful to stabilize the microcatheter and to prevent the kick-back of microcatheter into the parent artery. Further, we repeated the inflation of balloon catheter at the orifice to prevent the coil herniation whenever placing coils.
Complete obliteration of the aneurysm was achieved in 9 patients and subtotal occlusion in 4 patients. Two stents were needed in 1 patient because of stent migration into the aneurysm. A stent slipped down during withdrawal of the balloon catheter in 1 case without coil herniation or vessel injury. In follow-ups of 3 months to 7 years, there was no recurrence except for 1 case whose aneurysm regrew resulting in trapping of VA. The only procedure-related symptomatic complication was 1 case with transient abducens nerve palsy.
Stent supported coil embolization for wide-based vertebral aneurysms is a very useful and valuable technique. It permanenty prevents coil herniation and the rectification of parent artery flow. Although sufficient results were initially obtained, long term follow-up should be carried out.

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When dural arteriovenous fistula (DAVF) is associated with leptomeningeal venous drainage (LMVD), most cases have venous hypertension and concomitant venous congestion in the same areas due to reduced venous circulation. On the other hand, some cases in the DAVF with LMVD have no low-perfusion area. We studied this phenomenon. The subjects were 25 patients with DAVF. Of them, 16 cases had LMVD. Eleven had a low-perfusion area but 5 had no low-perfusion area. We analyzed this phenomenon in 5 cases. Two cases had anterior cranial fossa DAVF, 2 had tentorium DAVF, and 1 had transverse-sigmoid sinus DAVF. The characteristics of these DAVF are: 1) extra-sinusal type or pure leptomeningeal venous drainage, 2) low shunt flow, 3) existence of accessory route.

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In ruptured intracranial arterial dissection of the vertebrobasilar system, subsequent rupture is one of the poor prognostic factors. We analyzed the factors related to the subsequent rupture and compared the surgical results of craniotomy with those of intravascular surgery. Among 154 patients with vertebrobasilar arterial dissection, 92 presented with subarachnoid hemorrhage. Fifty-six patients were surgically treated: 35 had craniotomies (proximal occlusion or trapping), and 21 had intravascular surgery (internal trapping or proximal occlusion).
Subsequent rupture occurred in 29% (27/92), and was observed mostly on the day of onset. Among the various clinical and radiological factors, a history of arterial hypertension, a poor Hunt and Kosnik grade (3-5), and a pearl and string sign on the angiogram were significantly more frequent in the patients with subsequent rupture. The long-term outcomes in the craniotomy group were generally equal to those in the intravascular group. When the analysis was limited to acute stage, the results of the surgical treatment were unchanged between the 2 groups. In addition, the incidence of postoperative ischemic complication did not differ significantly between the 2 groups.
These results suggest that a history of arterial hypertension, a poor Hunt and Kosnik grade and the pearl and string sign are significant factors correlated with subsequent rupture. Surgical treatment may be indicated for patients with the above 3 factors, both craniotomy and intravascular surgery.

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I encountered 4 cases of blood blister-like aneurysm (3 ruptured and 1 unruptured) during the past 7 years. The unruptured one was accompanied by a ruptured internal carotid-ophthalmic aneurysm. These aneurysms constitute 3.4% of the total of 117 aneurysms managed by open or endovascular surgery during the same period. In these 4 cases, the lesion arose at the nonbranching site on internal carotid artery. The 4 aneurysms were operated upon via a transsylvian approach. A combination of both wrapping and clipping was done in 3 cases, and for the remaining 1 (ruptured) clipping only. The aneurysm managed by clipping only suffered postoperative massive bleeding because of an inappropriate obliteration of the proximal aneurysmal neck. The other 2 ruptured aneurysms that underwent both wrapping and clipping did not suffer any bleeding postoperatively, and 1 patient with an unruptured aneurysm has been in good condition. I detail the course of these 4 cases and problems concerning management for blood blister-like aneurysm.

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Surgical revascularization for moyamoya disease prevents cerebral ischemic attacks by improving cerebral blood flow (CBF). But little is known about the change in intraoperative cerebral hemodynamics and its effect on postoperative neurological status, including symptomatic cerebral hyperperfusion. To address this issue, we applied a novel infrared imaging system (IRIS-V infrared imaging system) for intraoperative monitoring of surface hemodynamics in 2 patients with moyamoya disease. We investigated the correlation between clinical, radiological findings, and changes of the gradation value in infrared imaging using imaging software. The camera showed apparent revascularization during surgery in both cases. In case 1, a 36-year-old male who presented with transient ischemic attack (TIA) underwent superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis with pial synangiosis. His cerebrovascular reactivity was significantly compromised as shown by preoperative IMP-SPECT. Intraoperative infrared imaging disclosed an increase in brain surface temperature due to increase in blood flow around the anastomosis. The gradation value gradually increased after recanalization of bypass during several minutes. Postoperative IMP-SPECT showed a focal increase in CBF around the site of anastomosis 1 day after surgery. Beginning on the next day, he suffered fluctuated aphasia, numbness and fine movement disturbance on his right hand for 7 days. Intensive blood pressure control relieved his symptoms, and he was discharged without neurological deficit. The anatomical location and the temporal profile of hyperperfusion accorded with the neurological deficits.
In case 2, a 29-year-old female who presented with TIA had already undergone surgical revascularization on the symptomatic right side. Then she underwent left STA-MCA anastomosis on the asymptomatic side with decreased cerebrovascular reserve capacity. Intraoperative infrared imaging disclosed no significant increase in brain surface color around the site of anastomosis except for the apparent revascularization through STA-MCA bypass. The gradation value did change significantly before or after recanalization of bypass. Postoperative IMP-SPECT showed a mild increase in CBF on the entire MCA territory without focal intense accumulation. Her postoperative course was uneventful, and she was discharged without neurological deterioration.
Characteristic patterns of the intraoperative cerebral hemodynamics as delineated by IRIS-V may be the optimal predictor for postoperative transient symptomatic hyperperfusion after direct bypass in patients with moyamoya disease.

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