Soji Shinoda

Platelet and leukocyte adhesion in the microvasculature at the cerebral surface immediately after subarachnoid hemorrhage.

OBJECTIVEPathophysiology after subarachnoid hemorrhage (SAH) caused by aneurysmal rupture has not been well examined. The purpose of this study was to observe platelet-leukocyte-endothelial cell interactions as indexes of inflammatory and prothrombogenic responses in the acute phase of SAH, using an in vivo cranial window method. METHODSSubarachnoid hemorrhage was induced in C57Bl/6J mice by using the endovascular perforation method. Intravital microscopy was used to monitor the rolling and adhesion of platelets and leukocytes that were labeled with different fluorochromes. Regional cerebral blood flow was measured with laser Doppler flowmetry. The platelet-leukocyte-endothelial cell interactions were observed 30 minutes, 2 hours, and 8 hours after SAH. The effect of P-selectin antibody and apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase, on these responses was examined at 2 hours after SAH, and compared with a different SAH model in which autologous blood was injected into the foramen magna. RESULTSSAH was accompanied by a 60% decrease in regional cerebral blood flow, whereas no changes in regional cerebral blood flow were observed on the contralateral side. SAH elicited time- and size-dependent increases in rolling and adherent platelets and leukocytes in cerebral venules. All of these interactions were attenuated by treatment with a P-selectin antibody or apocynin. There was no significant blood cell recruitment observed in the blood-injected SAH model. CONCLUSIONSAH at the skull base induced P-selectin- and oxygen radical-mediated platelet-leukocyte-endothelial cell interactions in venules at the cerebral surface. These early inflammatory and prothrombogenic responses may cause a whole-brain injury immediately after SAH.

Spontaneous Spinal Epidural Hematoma as a Potentially Important Stroke Mimic

Hemiparesis develops in response to a wide range of neurological disorders, such as stroke, neoplasms and several inflammatory processes. Occasionally, it may also occur due to a lesion located in the high cervical spinal cord. In this concise review, we describe the features of spontaneous spinal epidural hematoma, which should be included in the large list of stroke mimics. Various concerns regarding the diagnostic and therapeutic conundrums relating to the condition are also discussed.

Intraoperative monitoring during surgery for hypoglossal schwannoma

A 54-year-old man presented with an intracranial schwannoma of the hypoglossal nerve between the medulla and the left hypoglossal canal. The condylar fossa approach was used with intra-operative electromyography (EMG) monitoring of the lower cranial nerves. The tumor was then removed carefully without decreasing the tongue EMG responses. EMG monitoring enabled us to remove the tumor while maintaining the function of the hypoglossal nerve. Tongue EMG was easily recorded by stimulating the hypoglossal nerve fibers, which was useful in identifying the hypoglossal nerve and evaluating its function. This suggests that tongue EMG is a useful monitoring tool to enhance neurological outcome following removal of tumors in this region.

Clipping of a vertebral artery aneurysm behind the hypoglossal nerve under the monitoring of lower cranial nerves

Under an operative view, an aneurysm of the vertebral artery is located behind the lower cranial nerves. To prevent neurological deficits we employed electrophysiological monitoring while clipping an aneurysm of the vertebral artery. A 64-year-old woman had suffered a sudden severe headache in the morning. Computed tomography (CT) revealed a subarachnoid hemorrhage (SAH) and CT angiography revealed an aneurysm at a branching point of the left vertebral artery. The condylar fossa approach was taken while recording electromyography (EMG) of the lower cranial nerves. The aneurysm was located just behind the hypoglossal nerve and could not be clipped without strong traction of the hypoglossal nerve. Therefore, the hypoglossal nerve was divided to separate the lower two bundles of the hypoglossal nerve from the other bundles, and the clip was applied to the aneurysm between the nerve bundles without any change of the tongue EMG. The patient went home 10 days after operation with no neurological deficit. In conclusion, we report a case of a ruptured aneurysm of a vertebral artery, which was clipped while monitoring the lower cranial nerves. Tongue EMG monitoring enabled us to clip the aneurysm without nerve injury and revealed that the hypoglossal nerve near the hypoglossal canal can be divided into several bands without neurological deficit.