Hisahiko Suzuki

Anterior choroidal artery syndrome after surgery for internal carotid artery aneurysms.

We report five patients with anterior choroidal artery syndrome after surgery for internal carotid artery aneurysms. All patients suffered hemiparesis, and hemisensory loss and homonymous hemianopsia were identified in 2 patients. The characteristic triad of the syndrome was recognized in only 1 patient. Dominant and nondominant cerebral hemisphere signs have been reported in association with this syndrome, and 2 patients had a speech disturbance in our series. In previous reports, neurological deficits were mild and patient prognosis was good in anterior choroidal artery infarct, in spite of the fact that the artery supplied the corticobulbar and corticospinal tracts. This report suggests the possible causes of this syndrome after surgery for internal carotid aneurysms, which involve vasospasm after subarachnoid hemorrhage, mechanical obstruction, thromboembolism, and distortion of the aneurysm clip.

Spontaneous peritumoral haemorrhage associated with sinus confluence meningioma : Case report

BACKGROUND Torcular or sinus confluence meningioma is rare and surgically formidable. This reported sinus confluence meningioma was associated with peritumoral intracerebral hemorrhage. The surgical strategy and the mechanism of peritumoral hemorrhage are discussed. CASE DESCRIPTION A 42-year-old woman presented with a history of headache, vomiting, and cerebellar dysfunction for 2 months. Plain computed tomography (CT) scan and magnetic resonance imaging (MRI) demonstrated a high-density mass in the torcular region involving both lateral sinuses. MR angiography demonstrated complete occlusion of the left lateral sinus and straight sinus and stenosis of the right lateral sinus. Two years after her first operation she experienced sudden headache and left upper quadrant hemianopsia. Plain CT scan and MRI showed a hyperintense tumor in the torcular region with an intracerebral hematoma in the right occipital lobe. An angiogram demonstrated occlusion of the caudal part of the superior sagittal sinus, bilateral transverse sinuses, and straight sinus. Gross total removal of the tumor was done along with the left lateral sinus through a suboccipital and a supratentorial occipital craniotomy in the first operation. The patient underwent total resection of the tumor at second operation through a bilateral occipital and suboccipital craniotomy along with resection of the dura including the confluence, the caudal part of the superior sagittal sinus, the right lateral sinus, and the straight sinus. The postoperative course was uneventful and postoperative MRI showed total removal of the tumor. CONCLUSION Sinus confluence meningioma may present with peritumoral hemorrhage. Radical removal may be possible when the sinus confluence is completely occluded and there is good collateral drainage.

Congenital frontal bone defect with intact overlying scalp

An unusual case of a congenital frontal bone defect with intact overlying scalp and intact underlying dura mater is reported. Although spontaneous healing by the intact underlying dura mater by regeneration was expected, it did not occur. Cranioplasty was done for protective and cosmetic purposes. A review of the literature of congenital skull defects shows that spontaneous regeneration does not occur in this rare anomaly.

Cerebral ischemia alters glucose transporter kinetics across rat brain microvascular endothelium. Quantitative analysis by an in situ brain perfusion method.

The purpose of this study was to quantify the changes of blood-brain barrier glucose transporter kinetics following cerebral ischemia using an in situ brain perfusion technique. Sixty-four adult male Sprague-Dawley rats were divided into control and ischemia groups, and a four-vessel occlusion model was used to provide an ischemic insult. To obtain regional capillary permeability area products of glucose and regional perfusion fluid flow rates, the perfusion fluid was dually labeled with 2-deoxy[14C]glucose and [3H]diazepam, and the brain was perfused at a constant rate via the external carotid artery. After sampling tissues from the brain, dual scintillation counting was performed and both regional perfusion fluid flow rates and regional capillary permeability area products were calculated. We determined kinetic parameters, including Vmax, Km and Kd as described in the Michaelis-Menten equation, by the non-linear least squares method. In the ischemia group, a decrease in Vmax and an increase in Km were recognized, which mean decreases in the affinity and the number of functioning glucose transporters. These results suggest that cerebral ischemia downregulates the blood-brain barrier glucose transporters.

Navigational Surgery of the Skull Base and Other Vital Area Lesions Using the Mehrkoordinaten Manipulator (MKM) System

After introduction of the Mehrkoordinaten Manipulator (MKM; multicoordinate manipulator) system (Zeiss, Oberkochen, Germany) for frameless stereotactic microneurosurgery, we could determine the target point and the access route to the lesion preoperatively and outline the lesion and critical areas at a computer workstation. The system integrates stereotactically oriented computed tomography and magnetic resonance imaging with optical visualization by the microscope, displaying the spatial location of the point of focus in three sectional images. Additionally, the system superimposes the access route to the lesion, the target point with its location and direction, and the outline of the lesion and critical areas in the microscope. MKM-guided stereotactic microneurosurgery was performed in 14 patients with lesions involving the skull base, brain stem, and other deep sites. Because the lesion and surrounding structures of the skull base and brain stem maintained constant anatomical relationships during surgery, MKM-guided surgery provided easier access to the lesion, safer skull-base drilling, and better surgical results than classical microsurgical techniques. For small deep-seated lesions, the system could provide frameless stereotactic access to the lesion, but the outline of the lesion was not precisely superimposed because of displacement of the lesion and surrounding structures by cerebrospinal fluid outflow, brain retraction, and resection. The MKM system is very useful in its present configuration for lesions involving the skull base and brain stem. In the future, the MKM computer workstation should be given capability to interact with real-time intraoperative imagings to display small deep-seated lesions more accurately.

Effect of Osmotic Opening of Blood-Brain Barrier on the Learning of Rats

Osmotic opening of the blood brain barrier (BBB) has been used in the chemotherapy of brain tumors [2]. However, the potential risk of the procedure is still controversial [4, 5]. The purpose of the present study is to determine the effect of osmotic opening of BBB on learning of rats.