Knowledge of the mechanical properties of aneurysm clips is essential for their safe use in cerebral aneurysm treatment. The clip consists of a coil spring, leg, crossover, and blades. In the present article, closing forces, antiscissoring systems, and opening width of clips were reviewed. Closing forces of clips linearly increased from tip to base of clip blades. Scissoring was likely to occur when occluding the neck of the aneurysm with only the tips of long clip blades. Opening width depended on the clip leg.

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This study aimed to elucidate the surgery-related treatment outcomes in patients who underwent carotid endarterectomy (CEA) for radiation-induced carotid stenosis (RI-CS). We retrospectively reviewed the records of 11 patients who underwent CEA for RI-CS between July 2004 and April 2013. The end-points included ipsilateral and contralateral stroke, mortality, myocardial infarction, cranial nerve injury (CNI), wound complications, ipsilateral ischemic lesions on diffusion-weighted magnetic resonance imaging within 48 hours, and restenosis. Among the early outcomes (≤30 days), CNI occurred in one patient. Among the late outcomes (>30 days), restenosis occurred in one patient, who did not require revascularization. The only ischemic event that occurred in one patient was thrombosis of the carotid artery on the contralateral side. There were no other complications. RI-CS is often accompanied by the formation of vulnerable plaques. CEA can prevent undesirable outcomes in such cases. In addition, appropriate patient selection could avoid CNI and wound complications in patients with RI-CS. Simultaneous hybrid revascularization by CEA and carotid artery stenting may also be useful for RI-CS.

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This paper focuses on cases with difficult access for carotid artery stenting (CAS), and discusses management of such cases.
Of 135 consecutive patients who underwent CAS from January 2012 to December 2015 in our department, 11 (5.2%) had a difficult access route. In 3 cases with stenosis or elongation of the iliac arteries, we selected a smaller guiding sheath to pass through the artery. In one case with elongation of the abdominal aorta, a long and kink-resistant sheath was used to perform CAS. In 7 cases with a difficult femoral approach, CAS was performed via the right brachial artery. All 11 CAS procedures were uneventful without any perioperative complications.
Even in cases with a difficult access route, CAS can be performed safely with several techniques as described in this article.

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Background: Although endovascular therapy for large unruptured basilar tip aneurysms (BTAs) has been applied by using various techniques, still the condition is difficult to treat completely because of its high recurrence and retreatment rate. We compared different endovascular techniques for the treatment of large unruptured BTAs.
Methods: A retrospective study was conducted in 18 patients (12 women; mean age, 63.5 years) with large BTAs treated by using endovascular techniques between 2005 and 2014. We categorized the endovascular techniques into 3 groups as follows: 1) coil-only group, without any stent; 2) S-stent group, with a stent from the unilateral posterior cerebral artery (PCA) to the basilar artery (BA); and 3) Y-stent group, with 2 stents from the bilateral PCAs to the BA placed in a Y-shaped configuration. The bifurcation angle between the bilateral PCAs was also measured. We evaluated the initial embolization and radiological follow-up results.
Results: The mean aneurysm size and dome-to-neck ratio were 11.7 mm (10-15 mm) and 1.9 (1.5-2.5). The overall initial embolization results showed complete occlusion in 27.8% of the patients, neck remnant (NR) in 44.4%, and body filling in 27.8%. The overall radiological follow-up results showed unchanged status in 27.8% of the patients, improved status in 5.6%, minor recurrence in 16.7%, and major recurrence in 55.6%. The mean bifurcation angles in the S- (189.6° [156°-228°]) and Y-stent groups (198.8° [172°-224°]) were greater than that in the coil-only group (160.4° [135°-189°]). The mean post-treatment radiological follow-up period was 21 months (1-52 months) in the coil-only group, 12 months (8-15 months) in S-stent group, and 22 months (12-43 months) in the Y-stent group. Although the initial embolization results did not significantly differ between the technical groups, the recurrence rate was significantly lower in the Y-stent group than in the other two groups (p = 0.02). Additional treatments were performed, four in the coil-only group and one in the S-stent group. Three patients in the Y-stent group showed a change in bifurcation angle after treatment. Two procedural complications were observed, namely intraoperative hemorrhage in the coil-only group and asymptomatic thromboembolic stroke in the Y-stent group. Two patients in the coil-only group had aneurysmal hemorrhage after treatment.
Conclusion: Y-configuration stenting is one of the most important treatment techniques for large unruptured BTAs because it is safe and may improve the anatomical outcome in the medium and short terms.

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Background: Intracranial hemorrhage accounts for one-half of primary manifestations in adult-onset moyamoya disease. The hypothesis that extracranial-intracranial direct bypass reduces hemodynamic burden on fragile moyamoya vessels and thus prevents further bleeding remains unproven
Methods: The Japan Adult Moyamoya Trial is a multicenter, prospective, randomized controlled trial conducted by 22 institutions in Japan since 2001. Adult patients with hemorrhagic moyamoya disease were allocated either to conservative care or bilateral extracranial-intracranial direct bypass, and observed thereafter. All adverse events and rebleeding were monitored as endpoints. Five-year followups of all participants were completed in 2013, and the first results were published in 2014.
Results and Conclusions: Eighty patients were enrolled (surgical, 42; nonsurgical, 38). Incidence rates of primary and secondary events were significantly lower in the surgical group than in the nonsurgical group (3.2%/y versus 8.2%/y; p=0.048, and 2.7%/y versus 7.6%/y; p=0.042, respectively). The hazard ratio of the surgical group was 0.391 for primary endpoints and 0.355 for secondary endpoints. These results, along with those of further follow-up and subgroup analyses, may contribute to better treatment for hemorrhagic moyamoya disease.

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To clarify the optimal timing of surgical or endovascular treatment for patients with small-sized (<5 mm) unruptured intracranial aneurysms (UIA) with conventional follow-up, we retrospectively evaluated the characteristics of UIA that ruptured or enlarged during observation. From 1999 to 2014, 316 UIA (271 cases) were initially treated without surgical or endovascular intervention. Four ruptured and 17 grown UIAs were treated with clipping or coil embolization. In these cases, the ratio of the internal carotid to the posterior communicating artery and that of the anterior cerebral artery to the anterior communicating artery was 71%. Intraoperative findings revealed that the bleb formed during follow-up was observed as a very thin wall. Ruptured UIAs are prone to rapid growth. We conclude that location, growth rate, and bleb formation are useful to estimate the risk of rupture of smallsized UIAs during follow-up.

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We examined the clinical course of 32 patients with subarachnoid hemorrhage (SAH) in which the definitive diagnosis was delayed owing to an incorrect diagnosis during the initial hospital visit, although they presented with a headache, which was their chief complaint.
More than 80% of the patients had visited the hospital by the next day after symptom onset (21 patients visited on the same day; 6, 1 day later; and 5, 2 or more days after). All the patients visited the hospital on foot. Fourteen patients received an unspecified diagnosis (the most frequent diagnosis), 6 had a common cold, 2 had acute gastroenteritis, and 2 had a cervical spine sprain. Eleven patients initially visited medical institutions that had computed tomography (CT) scanners, among whom only 3 underwent CT, which showed mild SAH that went unnoticed by the attending physicians at that time. Eighteen patients visited the hospital 2 times, 10 visited 3 times, and 4 visited 5 times until a definitive diagnosis of SAH was made.
For walk-in patients, SAH was infrequently suspected, and the rate of CT scanning was low, even in those with a headache as the chief complaint.
In patients who revisit hospitals with the same complaint of a headache and show no improvement, SAH should be first ruled out during the definitive diagnosis.

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Background: The deep-lying cisternal part of the Sylvian fissure stem is structurally complex. A more developed posterior orbital gyrus (pOG) adds complexities to the dissection in that plane because adhesion between the pOG and the temporal lobe is much thicker and stronger in such cases. The purpose of this study was to suggest a method of preoperative estimation of the degree of development of the pOG by using only axial-view computed tomographic (CT) images.
Methods: First, we retrospectively classified 32 patients who underwent clipping of the anterior circulation aneurysms via the transsylvian approach at our institution into three types as follows, according to the degree of difficulty of the Sylvian fissure stem dissection evaluated using operative videos: type A, difficult; type B, normal; and type C, easy. Second, we hypothesized that an imaginary line (line D) joining the medial point of the Sylvian fissure with the limen insulae on axial CT images corresponds to the posterior rim of the pOG. Then, we evaluated the characteristics of line D in each case.
Results: Five cases were type A, and line D was curved with a backward convexity, with a mean length of 4 cm. Eleven cases were type B, and line D was curved with a backward convexity, with a mean length of 3.5 cm. Sixteen cases were type C, and line D was curvilinear or straight, with a mean length of 3.48 cm.
Conclusion: Preoperative evaluation of the morphological feature of the pOG is useful in estimating the degree of difficulty of Sylvian fissure stem dissection via the transsylvian approach.

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We reviewed 25 consecutive cases of cerebral cavernous malformations that were surgically treated in Okayama University Hospital between 2008 and 2014, and evaluated the surgical approach used for each lesion, its accessibility, navigation, monitoring, and the pre- and post-operative neurological statuses. Of 18 cases involving the supratentorial area, eight of the cavernous malformations were frontal lesions, five were temporal, one was parietal, two were occipital, and two were cavernous sinus lesions. Of seven cases involving the infratentorial area, three of the cavernous malformations were cerebellar lesions, one was midbrain, two were pons lesions, and one was located in the medulla. Microsurgery was performed with the help of intraoperative neuronavigation and neurophysiological monitoring. Most lesions that are to be approached surgically are close to or contact a pial or ependymal surface. Patients with long-term follow-ups (mean: 34.4 months) showed a mean modified Rankin Stroke Scale score of 1.0. Combination of neuronavigation and neurophysiological monitoring contributes to safety of operation and decrease of postoperative disability rate.

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Neurorehabilitation for acute stroke patients is essential for functional recovery and better prognosis. An exoskeleton-type robot, the “hybrid assistive limb” (HAL), has been developed for post-stroke care. Three types of HAL robots are currently available: bilateral leg type, single leg type, and single joint type. In this study, we aimed to investigate the clinical outcomes of a neurorehabilitation approach using multiple types of HAL robots in acute stroke patients with hemiparesis. The Brunnstrom stage scores and the modified Rankin scale (mRS) were used as outcome measures. These scales were evaluated when the HAL robots were introduced and patients were transferred to another hospital. Fourteen stroke patients (seven men, seven women; six ischemic stroke cases, eight hemorrhagic stroke cases) treated at Fukuoka University hospital were evaluated during the period between October 2013 and August 2015. The mean age of the cohort was 57.8 ± 11.0 years, and the patients underwent a total of 13.7 ± 7.9 HAL sessions. Brunnstrom stage and mRS scores were significantly improved after rehabilitation (p < 0.05). The present study showed that our neurorehabilitation approach using multiple types of HAL robots in stroke patients may be useful. We advocate that the rehabilitation approach should be tailored for each patient at various levels of recovery.

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We report a case of subarachnoid hemorrhage due to a rupture of an aneurysm at the right internal carotid artery-posterior communicating artery in a patient with Marfan syndrome. Since the patient had a history of aortic dissection that was treated conservatively, we selected clipping rather than coil embolization as the surgical strategy for the patient. She was surgically treated successfully, and discharged from our hospital without neurological sequelae 18 days postoperatively. From the findings of the present case in combination with a review of the literature, cerebral aneurysms in patients with Marfan syndrome may be developed due to the fragility of elastic membranes of major cerebral arteries, and we emphasize the importance of developing surgical strategy based on the fragility of elastic membranes.

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