Anterior communicating aneurysms are common compared with internal carotid artery or middle cerebral artery aneurysms and often require surgical intervention. It is not easy to dissect the interhemispheric fissure and the aneurysm because of the narrow surgical space, complicated vascular structures, and existence of important perforating arteries. The basal interhemispheric approach appears to be useful in observing all vascular structures around the Acom complex. To dissect an adherent and fragile interhemispheric fissure gently and with minimal invasion, we must first distinguish to which side of the frontal lobe a microvessel belongs at the microscopic level. It is important to retract the frontal lobe using a brain spatula and aspiration tube so that the dissection plane can be identified and pial injury avoided. It is also important when using the microscope to remember that the field of view is limited and can easily be obstructed by the incorrect use of surgical instruments. The basal interhemispheric approach requires advanced surgical techniques, which we will discuss in this article.

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The pterional approach is arguably the most popular surgical approach for neurosurgeons. Therefore, we should understand and experience this approach properly. The other surgical approaches can be learned readily once this approach is mastered. The principle aspect of the pterional approach is an appropriate exposure of the parasellar area without damaging the brain and vessels. There are various surgical options based on the primary disease and patterns of the sylvian veins. We will discuss about methods for widening the pterional approach, including manipulation of the sylvian vein and sphenoparietal sinus, the temporopolar approach, optic unroofing, anterior clinoidectomy, resection of the tuberculum sellae, and section of the dural ring.

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Basilar bifurcation aneurysms are generally treated via a transsylvian or subtemporal approach. The transsylvian approach has the disadvantage of inaccessibility to the posterior aspect of the aneurysm, while the subtemporal approach poses the risk of venous damage due to compression of the temporal lobe. Therefore, we attempted an anterior temporal approach, which provides a wider surgical field through safe retraction of the temporal lobe. The anterior temporal approach is a modified distal transsylvian approach that enables posterior retraction of the temporal lobe with minimum force by dissection of the superficial sylvian vein and anterior temporal artery from the temporal lobe. In cases in which it is impossible to dissect the superficial sylvian vein, the anterior temporal approach was switched to an extra-dural temporopolar approach. We describe herein the technical points and problems of the anterior temporal and extra-dural temporopolar approaches for basilar bifurcation aneurysms.

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Because the temporal lobe extends deeply into the middle cranial fossa anteriorly, the procedure of the subtemporal approach should be modified so as to avoid damaging the brain and the cortical veins by compression with retractors. To minimize compression damage to the temporal lobe it is necessary to perform the craniotomy along the middle cranial fossa, and to remove the zygomatic arch for supratentorial lesions, and to remove the petrous pyramid for infratentorial lesions. An extradural approach is useful as a means of preventing damage to bridging veins including Labbe's vein, but because the superior petrosal sinus and the tentorium are transected in the procedure by the anterior transpetrosal approach, the drainage pathways of the superficial sylvian vein (especially the sphenobasal vein and the sphenopetrosal vein) should be checked preoperatively. In this article we outline the surgical anatomy of the middle cranial fossa required for the subtemporal approach and variations in the venous drainage of the superficial sylvian vein, and then we describe the treatment of petroclival lesions by the anterior transpetrosal approach.

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Background: To evaluate the efficacy and toxicity of bevacizumab (Bev) as a new agent for molecular targeted therapy to treat recurrent high-grade glioma after failure using temozolomide (TMZ). Materials and methods: Five patients (age range, 32-77; Karnofsky performance scale, 40-70) with recurrent high-grade glioma who experienced treatment failure with TMZ were treated with Bev monotherapy since August 2009 at Kyorin University Hospital upon approval of the Institutional Review Board. The tumors consisted of anaplastic astrocytoma (2 cases), primary glioblastoma (2 cases), and secondary glioblastoma (1 case). Bev was intravenously administered at 10mg/kg at an every 2-week interval. Response was evaluated by Macdonald criteria. Results: Bev therapy was performed as second line therapy in three cases, and as third in two cases. The number of Bev cycles in each case was 1, 4, 4, 7, and 17, respectively. The tumor progressed in two cases within 3 months after Bev therapy was initiated. In one case, the Bev treatment was terminated after one cycle because of aggravation of meningeal dissemination, and thus was considered not evaluable. The maximum reduction in each tumor volume was 100%, 65%, 56%, and 33%, respectively. One patient had a partial response (PR), and three had stable disease (SD), resulting in an overall response rate of 25%. After initiation of Bev therapy, radiographic findings were rapidly improved in four evaluable patients, as well as their neurological status including restoration of motor function in two cases. Three patients had died of disease progression. High-grade adverse events were not observed including cerebral hemorrhage. On diffusion-weighted MR imaging, the apparent diffusion coefficient (ADC) values of all tumors which responded to Bev were higher than 1,100×10^<-6>mm^2/sec, whereas tumors with an ADC value lower than 1,100 did not. Conclusions: Bev monotherapy was found to be active and safe to TMZ-refractory, recurrent high-grade gliomas and resulted in substantial reduction of tumor volume with partial symptom relief. The duration of response, however, may not be long enough. Tumors that responded to Bev tended to show high ADC values. These data suggest that Bev may be an important molecular targeted therapeutic agent against TMZ resistant gliomas, and clinical trials of Bev in both recurrent and newly-diagnosed glioblastoma are currently underway in Japan and world-wide.

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Background and Purpose: Computational fluid dynamics (CFD) analysis is based on vessel region of interest from a "digital clone" produced by MRA, 3D-CTA and 3D-DSA. These angiographic images are not able to reflect extravascular information but intravascular flow, therefore, CFD technique is not able to predict aneurysm wall fragility directly. Here, we present the results of CFD analysis compared with intraoperative findings in a patient with unruptured internal carotid artery-posterior communicating artery bifurcation aneurysm presenting oculomotor nerve palsy. Methods: We investigated the relationship between the aneurysm dome and oculomotor nerve on clipping surgery and CFD results. In CFD analysis, wall shear stress (WSS) at the sites of parent artery, dome and contact zone to oculomotor nerve were calculated using the patient-specific model from 3D rotational angiography. In addition, two kinds of streamlines of blood velocity near the contact zone were evaluated. Results: WSS at the contact point was 0.44Pa, which is lower than that of the dome. 3D streamline of blood velocity was not observed around the contact zone. Surface stream near the contact zone was irregular pattern, however, that of bleb at the opposite side was linear pattern. Conclusion: CFD analysis provided key hemodynamic information that low WSS and irregular surface streamline could be related to the mechanism of the growing component in unruptured cerebral aneurysms.

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Carotid endarterectomy (CEA) has been established as an effective treatment of severe carotid artery stenosis to prevent the occurrence of cerebral ischemic event in the chronic stage. However, the safety and efficacy of emergency CEA for an impending stroke case such as crescendo transient ischemic attack (TIA) and progressing or fluctuating minor stroke is still controversial. We report the case of a 75-year-old man who presented with fluctuating cerebral ischemic symptoms due to severe internal carotid artery stenosis and anemia caused by gastrointestinal hemorrhage from advanced sigmoid colon cancer. He was administered anticoagulants and anti-platelet medication, and then blood transfusion was performed; however, the ischemia persisted. Thus, medical intervention was insufficient and emergency CEA was performed. Thereafter, cerebral ischemia resolved and radical colon resection was safely performed. Careful evaluation and accurate timing are very important factors that influence the safety and efficacy of emergency CEA.

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