The natural history of incidentally found non-thrombosed fusiform aneurysms of the vertebral artery has not yet been determined. We retrospectively analyzed 10 asymptomatic cases confirmed by head MRI and cerebral angiography. All were males aged from 42 to 73 years old (mean±SD 56.3±9.90). Three cases were found in a brain doc, another 3 were incidentally found in the workup of other neurological disease, and 4 were found in screening for chronically sustained headache. The patients’ vascular risk included hypertension, hyperlipidemia and smoking.
The aneurysms were found more often on the right (8 out of 10). The aneurysmal wall contained major cortical arteries in all cases except 1 who received endovascular trapping. The endoview mode obtained from 3D-DSA revealed smooth arterial surface seen from the inside. The treatment option was vascular risk control in most cases, with the exception of 2 endovascular procedures according to the patients’ will. Compared with the symptomatic cases, the characteristics of the asymptomatic cases resembled those of cases with cerebral infarction such as age, sex and natural history. It may be that the asymptomatic cases represent the chronic phase of unnoticed dissection of the vertebral artery. The endosurface view obtained from 3D-DSA might reflect the change they had taken.
Although based on only a limited number of cases, this study indicates the possibility of a benign natural history of asymptomatic non-thrombosed fusiform aneurysm of the vertebral artery.

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Although clinical guidelines are defined as a systematically constructed document that assists decisions of both practitioner and patient, usual guidelines are a summarized list of evidence-based references by specialists and do not consider the concerns or preferences of the patients or their families. The purpose of this study was to assess 2 decision support tools (a Web-based tool and a DVD) in the decision making process for patients with unruptured cerebral aneurysms. Questionnaires were used to assess the effectiveness and usability of these tools and patients’ satisfaction and conflicts in decision making in treatment selection. Most patients recognized the effectiveness of decision support tools and their knowledge tended to increase with the use of these tools.
Guidelines and decision support tools for the treatment of unruptured cerebral aneurysms should be constructed considering current clinical information of the risk of aneurysms, treatments, and the patient’s point of view.

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Over the past 11 years, a total of 322 patients with UCAs (unruptured cerebral aneurysms) were seen in our hospital, and 165 patients were observed. Among these 165, 69 were followed up annually with MRA or 3D-CTA. The status of the remaining 96 patients could not be radiologically followed up. In patients who were radiologically followed up, the aneurysms ruptured in 2 (rupture rate was 1.0% per year) and enlargement was noted in 8 (4.1% incidence per year). In unobserved patients, rupture occurred in 7 (2.9% per year). Aneurysm size was the sole factor related to rupture, whereas younger age and multiplicity of UCAs were significantly related to the growth of aneurysms. Aneurysms in female patients tended to increase in size over time.
The results indicated that follow-up with 3D-CTA or MRA at certain intervals has the potential to detect enlargement of UCAs before rupture.

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It is mandatory to develop microsurgery training methods for young neurosurgeons because the number of surgical cases has been decreasing due to the development of alternative therapy for neurovascular diseases such as radiosurgery, endovascular coil embolization, and stenting. Here we describe our training methods for microvascular anastomosis for young neurosurgeons as well as senior staff with minimum cost and maximum convenience. Our microsurgical training system consists of microanastomosis using an artificial tube and actual surgical microscope in the operating room. The depth and the size of the practical operative field can be changed using simple boxes made by each practitioner. In addition to the basic anastomosis technique, a trainee can anastomose artificial tubes in various surgical environments using an artificial skull and plastic brain with brain retractor. Training for turning the microneedle is also useful for practical microsurgery.
Although there are several training systems for microsurgery, including experimental mammals such as rats and/or chicken wings, it is important for young neurosurgeons to practice micro-anastomosis in an environment similar to that of their institutions.

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Fine movements of a non-dominant hand and coordination of both hands are essential for safe and reliable achievement of microsurgery. We carried out a microsurgical training exercise using a chicken wing artery, in which an end-to-side anastomosis was performed by a dominant or a non-dominant hand for 5 days running for each hand.
This practice demonstrated that the non-dominant hand training not only improved the fine movements of a non-dominant hand but also established skillful techniques of a dominant hand. This may be explained by the bilateral motion transfer phenomenon seen in mirror image learning applied for rehabilitation of apoplexy patients with hemiplegia.

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Clipping via keyhole surgery is one option for treating cerebral aneurysms. We have developed a lateral supraorbital keyhole approach to clip unruptured anterior communicating artery (ACom) aneurysms. This approach is a variant of the supraorbital keyhole approach, but extends the mini-craniotomy to the sphenoid ridge. The key point is epidural flattening of the bony spines on the orbital roof to provide an improved intradural surgical corridor.
Thirty consecutive patients with unruptured ACom aneurysms were treated via the lateral supraorbital keyhole approach (maximum diameter: 30.9±3.6 mm, minimum diameter: 24.0±2.5 mm) without mortality or permanent morbidity. The aneurysm size was 3 to 11 mm (mean: 6.5±2.0 mm) and two-thirds of the aneurysm domes pointed anteriorly or inferiorly. Evaluation with Hasegawa’s dementia scale and the mini-mental scale examination did not detect any significant changes in the patients before or after surgery. The mean postoperative hospitalization period was 2.7±3.0 days.
The lateral supraorbital keyhole approach is a safe surgical option to treat relatively small ACom aneurysms oriented anteriorly or inferiorly.

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We evaluated the applicability of the interhemispheric approach to the A3-4 segment of distal anterior cerebral artery (dACA) aneurysm with a horizontal head position. Between April 2006 and August 2009, we had 6 cases with a dACA aneurysm and performed neck clipping. The patient’s head was placed horizontally, usually with the left side up. A parasagittal craniotomy on the right side that crossed the midline and exposed the superior sagittal sinus was performed. The pericallosal artery in the corpus callosum cistern was exposed and proximally traced to the neck of the aneurysm. The exploration of the A2 segment for proximal control was accomplished just anterior to the genu of corpus callosum. All aneurysms were clipped successfully. There was no surgical mortality or morbidity. The horizontal head position permits gravity to retract the downside hemisphere and open the interhemispheric fissure while the falx retracts the upside hemisphere.
The interhemispheric approach with horizontal head position can be used to treat dACA aneurysm safely and successfully.

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Bow hunter stroke is a symptomatic vertebrobasilar insufficiency caused by stenosis or occlusion of the vertebral artery at the C1-C2 level on head rotation. The appearance of the symptom affects the patient’s ADL, and occasionally it causes cerebral infarction in the cerebellum or brain stem. When conservative treatment is not effective, surgical treatment becomes necessary. Two techniques are known: C1-C2 posterior fusion and decompression of the vertebral artery, but which technique is better remains controversial.
We describe 21 cases of Bow hunter stroke. In 21 cases, decompression of the vertebral artery was performed in 9 cases, and C1-C2 posterior fusion was performed in 12 cases. We compared the results of the 2 techniques in relation to recurrence of clinical symptoms, complications, and ADL after treatment. In groups treated by posterior fusion, the range of head motion was reduced, but there was no postoperative recurrence of clinical symptom or disturbance of ADL. On the other hand, in groups treated by decompression of the vertebral artery, there was no limitation of head motion, but in 3 cases clinical symptoms recurred. In 2 of the 3, it was necessary to add C1-C2 posterior fusion. In 1 of the 3, brain stem infarction occurred. All events occurred within 3 months after operation. In 2 cases of added posterior fusion, symptoms did not recur. Decompression of the vertebral artery may cause recurrence of the symptom within 3 months after surgery because of formation of adhesions of the vertebral artery to surrounding structures, which is impossible to predict or prevent.
Therefore, we conclude that C1-C2 posterior fusion is more useful than decompression of the vertebral artery.

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When thalamic hemorrhage is accompanied by severe intraventricular hematoma, the prognosis is poor. Spontaneous thalamic and intraventricular hemorrhage is usually treated by external ventricular drainage for obstructive hydrocephalus. However, drainage occlusion, meningitis and residual hematoma are often troublesome in actual clinical practice. For such severe cases, we performed direct hematoma evacuation by the frontal mini-craniotomy transcortical approach in recent years. The present study evaluated the outcome and complications in 14 patients with spontaneous thalamic and intraventricular hemorrhage treated by frontal mini-craniotomy hematoma evacuation with ventricular drainage and 16 patients treated by only external ventricular drainage. There were no significant differences between the 2 groups with respect to age, clinical grade, hematoma volume, hematoma location and postoperative epilepsy. There was also no significant difference in postoperative outcome between the 2 groups. However, patients treated by frontal mini-craniotomy were less likely to require days of ventricular drainage settlement, had suffered meningitis less frequently and had good hematoma evacuation rate compared with those undergoing only external ventricular drainage.
Frontal mini-craniotomy is a simple and effective method for hematoma evacuation that causes fewer complications.

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We report a rare case of a 15-year-old male with multiple saccular aneurysms. He experiences dizziness while riding a bicycle and fell. On admission, he was drowsy but had no other neurological deficits. A brain CT scan demonstrated diffuse subarachnoid hemorrhage. A cerebral angiogram revealed a left internal carotid artery-anterior choroidal artery (IC-Ac) aneurysm (AN) with a bleb, a left basilar artery-superior cerebellar artery (BA-SCA) AN, a small left anterior cerebral artery (A1A2) AN and a right M1M2 portion of middle cerebral artery (M1M2) AN. The left IC-Ac AN seemed to be ruptured. The left ruptured IC-Ac and left unruptured BA-SCA ANs were clipped on Day 1. About 1 year later the right M1M2 AN was clipped, but the left A1A2 AN could not be clipped via a trans-sylvian approach because of its high position at 1 stage operation. The small left A1A2 AN was periodically followed up with MRA for 3 years. Since it increased in size, it was clipped via an inter-hemispheric approach. All 4 ANs were completely clipped on postoperative angiogram. Adolescents and adults display different clinical features in ANs.
The biggest treatment difficulty is the higher incidence of giant ANs of the IC bifurcation and vertebro-basilar ANs in adolescents than in adults, and thus therapeutic strategy should be considered on a case-by-case basis.

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A 73-year-old male presented with hypertensive intracerebral hemorrhage that mimicked middle cerebral artery aneurysm on CT angiography. Nonenhanced CT showed hemorrhage in the right basal ganglia with extension to the sylvian fissure. CT angiography (CTA) revealed an aneurysm-like enhancement adjacent to the right M3 branch to M4. The location of the lesion was atypical and the neck was obscure for a middle cerebral artery aneurysm. On CTA performed 1.5 hour after initial CTA, the aneurysm-like enhancement had vanished. The patient underwent hematoma evacuation by craniotomy. No aneurysm was found in an intraoperative view or on digital subtraction angiography performed after the operation.
We considered the aneurysm-like enhancement on CTA as contrast extravasation in the acute stage of hypertensive intracerebral hemorrhage.

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