Although many cerebral vascular anomalies are widely recognized, others are less well known or unclassified. Accessory middle cerebral artery (MCA) and duplicated MCA are among uncommon anomalies. We present a very rare case of subarachnoid haemorrhage due to rupture of a saccular aneurysm arising from a duplicated middle cerebral artery which was associated with an accessory middle cerebral artery.

A 35-year-old woman presented with a bilateral thalamic glioma manifesting as dysesthesia over the left side of the body and mental deterioration. T 1 -weighted magnetic resonance imaging revealed enlarged bilateral thalami with homogeneous isointensity and no enhancement after gadolinium administration. Histological examination of a stereotactic biopsy specimen identified anaplastic astrocytoma. Radiotherapy and chemotherapy failed to arrest tumor growth. She subsequently died. Magnetic resonance imaging and clinical findings support the view that bilateral thalamic gliomas represent a distinct clinicopathologic entity among thalamic tumors.

The trans-sylvian approach is one of the most frequently employed neurosurgical procedures, but it is difficult for medical students to understand the approach stereoscopically. A three-dimensional model equipped with an arachnoid membrane and sylvian vein was developed which can be repeatedly used to simulate surgery for the education of medical students and residents in the trans-sylvian approach. The model was prepared using existing models of the skull bone, brain, and cerebral artery. Polyvinylidene chloride film, commonly used as plastic wrap for food, was adopted for the arachnoid membrane, and wetted water-insoluble tissue paper for the arachnoid trabeculae. The sylvian vein was prepared by ligating woolen yarn with cotton lace thread at several sites. Students and residents performed the trans-sylvian approach under a microscope, and answered a questionnaire survey. Using this model, simulation of division of the arachnoid membrane and arachnoid trabeculae, and dissection of the sylvian vein was possible. In the questionnaire, the subjects answered 8 questions concerning understanding of the stereoscopic anatomy of the sylvian fissure, usefulness of the simulation, and interest in neurosurgical operation using the following ratings: yes, very much; yes; somewhat; not very much; or not at all. All items rated as`yes, very much' and`yes' accounted for more than 70% of answers. This model was useful for medical students to learn the trans-sylvian approach. In addition, repeated practice is possible using cheap materials, which is advantageous for an educational model.

Summary:We report here 3 cases of major artery injury during surgery for cerebral aneurysms. Case 1 was 63-year-old female with unruptured aneurysms on the right distal anterior cerebral artery (D-ACA) and right middle cerebral artery. Upon release of the temporary clip on the proximal anterior cerebral artery after clipping of the D-ACA aneurysmal neck, the aneurysm was avulsed together with the clip on the aneurysmal neck by the clip applier. The arterial defect was closed with 2 stitches and clipped to maintain the vessel structure.Case 2 was 49-year-old female with ruptured left anterior wall aneurysm of the internal carotid artery (ICA). When a clip was placed at the aneurysm covered with blood clots, the aneurysm ruptured at its base and a large hole appeared in the wall of the artery. The defect in the wall was closed with 3 stitches and reinforced with 2 clips parallel to the ICA axis.Case 3 was 52-year-old male with left paraclinoid unruptured aneurysm. For the purpose of proximal control, the cervical ICA was exposed and prepared for temporary ligation by silicon rubber tape. During the clipping procedure for the aneurysm, the ICA was temporarily ligated many times, resulting in wall dissection at the ligated portion. After the blood flow was stopped, the ICA was incised and the clots in the wall were removed. The dissected intima was cut off and 3 tacking sutures were placed on each side of the proximal and distal ends of the dissection.Injury to a major arterial trunk rarely occurs during surgery for cerebral aneurysms. Even so, microsurgical instruments for stitching in a deep field should be prepared for these sudden events for successful surgery.