A nationwide study (VAD 2013) was conducted over a year (January 1 to December 31, 2011) to elucidate the recent trends of the clinical features, radiographic findings, treatment, and outcomes of non-traumatic intracranial arterial dissection in the vertebrobasilar system. Here, we present the outline of the study.
In this study, 632 patients from 172 neurosurgical institutes were enrolled. They were divided into 3 groups: (1) hemorrhage group consisting of 193 (30.5%) patients with subarachnoid hemorrhage; (2) ischemia group consisting of 209 (33.1%) patients with brain infarction or transient ischemic attack; and (3) headache group consisting of 230 (36.4%) patients. The following patient characteristics were recorded: age, sex, location of arterial dissection, initial radiographic findings, and serial changes in these findings, treatment, follow-up periods, and mid-term outcomes. The outcomes were evaluated using the modified Rankin scale (mRS), and a good outcome was defined as an mRS score of 0-2.
Results: (1) Age and sex: The median age of the patients was 53, 52, and 50 in the hemorrhage, ischemia, and headache groups, respectively. Men outnumbered women in all the 3 groups; especially, in the ischemia group, the number of men was remarkably higher than that of women. (2) Location of arterial dissection: The vertebral artery was affected in 85% of the patients in both the hemorrhage and ischemia groups, and in 97% of the patients in the headache group. (3) Radiographic findings: Fusiform dilatation and pearl-and-string sign were the common findings in the hemorrhage group, whereas tapering string and occlusion were more frequent in the ischemia group. Regarding serial changes of the radiographic findings, improvement of the finding was the most common, followed by no change in both the ischemia and headache groups.(4) Treatment: Surgical treatment was administered to 82% of the patients, and endovascular surgery was the main procedure adopted for the hemorrhage group. In contrast, conservative treatment was administered to a majority of the patients in the ischemia and headache groups. Antithrombotic therapy was administered to 79% of the patients in the ischemia group, and to 17% in the headache group. (5) Follow-up periods: The median follow-up period was 5, 10, and 12 months in the hemorrhage, ischemia, and headache group, respectively. (6) Mid-term outcomes: Good outcomes were observed in 57% of the patients in the hemorrhage group; however, 26% of the patients in this group died. Furthermore, good outcomes were observed in 85% and 98% of the patients in the ischemia and headache group, respectively; the mortality rate in these 2 groups was rather low.
These data were compared to those of the previous studies, such as the nationwide study in 1995-96 by Yamaura et al. The number of patients in the headache group was higher in this than in the previous studies. The number of patients with hemorrhage who received surgical treatment, especially endovascular surgery, was higher in this than in the previous studies. Furthermore, the number of patients in the ischemia and headache groups who received antithrombotic therapy was higher in this than in the previous studies. However, the clinical features, radiographic findings, and outcomes did not differ significantly between the present study and the previous studies.

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To investigate the current status of management and outcomes in patients with non-traumatic hemorrhage after intracranial vertebrobasilar artery dissection (VAD), we conducted a nationwide study over a period of 1 year (2011) in Japan.
Of 632 patients with VAD, 193 patients were enrolled for the onset of hemorrhage. The following patient characteristics were recorded: age, gender, location of arterial dissection, radiographic findings, presence or absence of rebleeding, treatment, follow-up periods, and mid-term outcomes. The outcomes were evaluated using modified Rankin scale (mRS), and a good outcome was defined as an mRS score of 0-2.
Regarding disease severity, Hunt and Kosnik (HK) grade-4 or grade-5 disease was observed in 48.2% of the patients. Hydrocephalus was detected in 43.6% of the patients. Rebleeding was observed in 21.5% and usually occurred within 24 hours after the onset of hemorrhage. For the prevention of rebleeding, surgical treatment, including 33 craniotomies (group C) and 127 endovascular surgeries (group E), was administered to 160 patients (82.9%). Conservative or medical treatment was administered to the remaining 33 patients (group M). Trapping was the most frequent procedure performed for the patients in groups C and E. Bypass surgery was performed in 11 patients (6.9%). Postoperative intracranial complications occurred in 23.8%, and the most common complication was ischemic events. In group C, a higher incidence of ischemic complication was observed in patients treated with trapping than in those treated by proximal occlusion. However, in group E, the incidence of ischemic events did not differ between patients treated by trapping and those treated by proximal occlusion.
At the final follow-up, 56.5% of the patients achieved a good final outcome (mRS score, 0-2) and 25.9% of the patients died during the follow-up. After the treatment, 54.5% of the patients in group C, 60.6% in group E, and 42.4% in the medical treatment group showed good outcomes.
Advanced age, hydrocephalus, rebleeding, posterior inferior cerebellar artery dissection, and a high HK grade were associated with poor outcomes.
Endovascular surgery has been a highly common treatment option during last 2 decades. The outcomes and prognostic factors of hemorrhage in the VAD patients were similar to those previously reported.

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The first nationwide survey for nontraumatic intracranial vertebrobasilar dissection (VAD) was conducted in Japan 20 years previously. The optimal treatment for ischemic VAD is still a controversial topic. We conducted a nationwide study over a 1-year period (2011) to examine the present status of management, outcomes, and factors influencing the outcome.
The response rate for this survey was 15.6% (172 responses/1104 total facilities). Of the 632 patients with VAD that were enrolled to this study, 209 patients had ischemic VAD. The median age at onset was 50 (21-85) years and 78.5% of the patients were men. In this cohort, 56.7% of the patients experienced headache at the onset. Wallenberg syndrome, motor paresis, sensory disturbance, and cranial nerve symptoms were also observed in 36.9%, 22.4%, 46.7%, and 25.8% of the patients, respectively. Symptomatic deterioration and recurrence were observed in 44 patients (21.1%).
With regard to patient management, 78.5% of the patients were treated with antithrombotic therapy. These treated patients had relatively severe neurological symptoms. No subarachnoid hemorrhage was observed in the ischemic VAD patients during the follow-up period. At the final follow-up, 72.4% of the patients achieved a favorable outcome (modified Rankin scale 0 to 1). Basilar artery dissection was related to clinical deterioration during the treatment, and diabetes mellitus was associated with a poor final outcome.
The clinical feature, radiological findings, and outcomes were found to be similar between the present and previous reports. In the current management of ischemic VAD patients in Japan, there is considerable variability in the use of antithrombotics. Patients with severe symptoms and/or supratentorial infarction frequently received antithrombotic therapy. To evaluate the efficacy of antithrombotic in the treatment of ischemic VAD, a prospective study is necessary. Moreover, the treatment selection bias can hardly be eliminated in a non-randomized trial.

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The incidences of subarachnoid hemorrhage (SAH) in Finland and Japan are the highest in the world, with about 20-23 cases per 100,000 persons per year. Since the report of the International Subarachnoid Aneurysm Trial (ISAT) was published, the use of intravascular coil embolization (CE) for cerebral aneurysm has become more frequent worldwide. In this paper, we discuss the current situation of therapy for cerebral aneurysm in Japan according to the data of our institute, the Japan Standard Stroke Registry Study, and the Japan Neurosurgical Society.
From 1999 to 2013, 543 cases of ruptured saccular cerebral aneurysms were treated in Shimane Prefectural Central Hospital. According to data, most cases occurred in men in their fifties and in women in their seventies. The mean sizes of ruptured cerebral aneurysm according to site were 7.4 ± 4.1, 7.0 ± 5.4, and 5.5 ± 2.5 mm in the internal carotid artery posterior communicating artery, middle cerebral artery, and anterior communicating artery, respectively. Aneurysms smaller than 5 mm account for 187 (34.4%) of the cases.
According to the Japan Standard Stroke Registry Study, the poor outcome rates (modified Rankin scale score, 3-6) according to the ISAT criteria were 18.3% and 24.2% in the surgical clipping (SC) and CE groups, respectively. These rates were superior to the ISAT data (36.4% for SC and 25.4% for EC). According to the survey of the Japan Neurosurgical Society from 2001 to 2011, the prevalence of cerebral aneurysm cases treated with clipping decreased from 88.2% in 2001 to 71.2% in 2011. The number of ruptured cerebral aneurysms treated with clipping also decreased. However, the frequency of clipping for unruptured cerebral aneurysm was increasing.

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Giant and complex intracranial aneurysms are associated with poor prognosis because of the high risk of rupture, mass effects on the surrounding brain tissue, and a propensity to lead to the formation of emboli in the downstream vascular territories. The preferred treatment for these aneurysms is direct clipping, but this technique is typically unfeasible. Reconstruction of the main trunk (such as the internal carotid artery, middle cerebral artery, anterior cerebral artery, vertebral artery, or basilar artery) and aneurysm trapping may enable safe treatment for the lesion and simultaneously reduce the risk of ischemic complications. For safe reconstruction of the main trunk, back-up bypass and pressure monitoring during the operation are important. Back-up bypass can serve as a precautionary measure during vessel reconstruction if the reconstructed artery does not function adequately.
Monitoring of the pressure in other branches of the back-up bypass is important for the estimation of performance of the reconstructed artery. If the main trunk is occluded as a blind end, delayed thrombosis may be observed. Thus, the preoperative strategy must avoid formation of a blind end. In case the perforating artery is injured, reconstruction using the superficial temporal artery or occipital artery should be attempted.

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Purpose: Endovascular coil embolization for very small aneurysms (≤3mm) is considered to be technically challenging because of technical difficulties and high complication rates. We aimed to evaluate the results of endovascular coil embolization for very small aneurysms.
Materials and Methods: Between 1998 and 2012, 48 very small aneurysms in 45 patients were treated with coil embolization. Twenty-seven aneurysms were ruptured, and 21 were unruptured. Of the 21 unruptured aneurysms, 8 were associated with ruptured aneurysm and 13 were detected incidentally by routine examination. We assessed the procedural complications, type of the first coil, total number and length of the coils used, initial angiographic results immediately after the procedure, and shortterm follow-up angiographic results.
Results: Two aneurysms ruptured during the procedure but did not lead to any neurological deficit. One thromboembolic complication occurred and led to hemiparesis. The procedure-related morbidity and mortality were 2.2% and 0%, respectively. Extrasoft and ultrasoft coils were mainly used for the first coil. The total number of the coils used ranged from 1 to 3 in 70% of the cases. The total length of the coil used was <10cm in 60% of the cases. Immediately after coil embolization, complete occlusion, neck remnant, and dome filling were achieved in 23 (50%), 8 (17%), and 16 aneurysms (33%), respectively. None of the cases had rerupture and retreatment from initial treatment to follow-up. Some incompletely occluded aneurysms spontaneously led to complete occlusion during the follow-up period.
Conclusion: Coil embolization of very small aneurysms is technically feasible. Appropriate selection of patients and careful consideration of the technical issues in the treatment of these aneurysms are essential to achieve technical success. A delicate procedure is required to prevent complications during the procedure.

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The introduction of ONYX liquid embolic system (Onyx) has enabled us to adopt a new treatment approach for brain arteriovenous malformation (AVM), by using microsurgical AVM resection following Onyx embolization. The aim of the present report was to evaluate our results after the application of this strategy, with emphasis on technical considerations for microsurgical resection of Onyx-embolized AVM. From January 2010 to June 2014, 11 consecutive patients with AVM were treated by using microsurgical resection in combination with Onyx embolization. The patients' mean age at the beginning of the treatment was 35, and 8 patients presented with hemorrhage. The embolization achieved a volume reduction more than 80% in 6 patients. One patient experienced transient neurological aggravation after the embolization. One patient exhibited partial visual field defect after surgery, resulting in a decreased mRS score of 1. Postoperative angiography showed complete removal of the nidus in 10 patients, and the remaining underwent radiosurgery for the residual nidus.
Regarding the technical aspects of microsurgery for Onyx-embolized AVM, we noted some advantages, including 1) excellent visibility in the operative field, 2) easy creation of the dissection plane between the nidus and white matter, 3) presence of collapsed drainers, which can be resected at the early phase of the surgery. On the other hand, extensively embolized nidus was firm and less elastic, making retraction difficult. In conclusion, it is important to consistently perform Onyx embolization as a presurgical procedure in accordance with the usage standard approved in Japan. Such a perspective will make this new challenging technique safer and more effective to perform.

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The aim of this study was to elucidate the incidence of a depressive state at a mean followup of 22 years in patients with moyamoya disease. Furthermore, this study examined the possibility of frontal lobe dysfunction influencing the occurrence of depressive state. Thirty patients were assessed using the Zung Self-rating Depression Scale, the Quick Inventory of Depressive Symptomatology-J, and the Frontal Assessment Battery in an outpatient setting. Eight patients (26.7%) were found to have developed a depressive state. Frontal lobe function, disease duration, and headache were statistically related to the occurrence of a depressive state. Further studies are needed to clarify the correlation between a depressive state and frontal lobe dysfunction; however, patients with moyamoya disease should be evaluated and treated as needed for a depressive state.

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Appearance of cavernous malformations (CMs) on magnetic resonance imaging varies depending on the time phase of hemorrhage. We retrospectively analyzed the temporal profile of CM appearance on MRI during its natural course. Of the 33 cases included in this study, 20 (8 with symptomatic hemorrhage, 11 with incidentally diagnosed CM, and 1 with residual lesion after surgery) were followed up with repeated MRI for more than 6 months. Symptomatic hemorrhage occurred in 2 cases during the follow-up period. MRI findings and hemorrhage resolution changed over time. Asymptomatic hemorrhage was detected as an additional high intensity signal on T1-weighted images in 3 cases. A temporal change in the MRI appearance of CMs with symptomatic hemorrhage, which progressed from Zabramski type I to II and subsequently III, correlated predominantly with neurological improvement. In contrast, asymptomatic hemorrhage was detected in the absence of clinical symptoms in some cases. CMs are a cerebrovascular anomaly demonstrating dynamic changes that include symptomatic hemorrhage and its consequent resolution as well as micro-hemorrhage without neurological deterioration.

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Brainstem arteriovenous malformations (AVMs) are relatively rare among intracranial AVMs, and careful treatment should be planned to resect the nidus of AVM because of high risk of bleeding and high morbidity and mortality after hemorrhage. Moreover, due to the high rebleeding risk in the treatment of brainstem AVM, the nidus should be removed as soon as possible, but surgical resection of brainstem AVMs is difficult and challenging because of their deep-seated location and proximity to vital structures.
We report the case of a 26-year-old female patient who presented with hemorrhagic midbrain AVM, and hydrocephalus due to intraventricular hematoma. We performed removal of the hematoma block in the bilateral, third and fourth ventricle, and surgical resection of the AVM nidus through the anterior interhemispheric transcallosal, trans-third ventricle approach because she experienced repeated hemorrhage after ventricular drainage. The disappearance of the nidus was confirmed with postoperative angiography.
Although radiosurgery should be actually applied to the brainstem AVMs because intrinsic brainstem AVMs are difficult to be resected without causing any serious neurological deterioration, we propose that microsurgical resection through the transcallosal, trans-ventricle approach could be an option for small nidus of brainstem AVM with intraventricular hemorrhagic presentation.

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A 55-year-old man, who had experienced a headache for two days and then suddenly lost consciousness, presented at our hospital. Computed tomography (CT) revealed a right side dominant subarachnoid hemorrhage mainly in the right basal cistern and posterior fossa. Both CT angiography and cerebral angiography revealed the pearl-and-string sign in the intracranial portions of the bilateral vertebral arteries (VAs), involving the origin of the posterior inferior cerebellar arteries (PICAs). Trapping of the dissecting aneurysm (DA) in the right VA with an occipital artery-PICA anastomosis was performed as an emergency surgery. The postoperative course was uneventful; however, he suddenly lost consciousness on the seventh postoperative day. Both CT and CT angiography revealed a hemorrhage and an increase in the size of the left VADA. The patient died 2 days later. The autopsy revealed a rupture of the left VADA. The increase in the hemodynamic stress to the contralateral VA had induced the VADA rupture. Thus, during surgeries involving the bilateral VADAs, it is important to not change the hemodynamic stress to the unilateral VA.

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