2010 Fiscal Year Final Research Report

Identification of activated area after intraoperative transcranial electrical stimulation for motor evoked potential

Research Project

Project/Area Number	21791368
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Single-year Grants
Research Field	Cerebral neurosurgery
Research Institution	Kyushu University
Principal Investigator	HASHIGUCHI kimiaki Kyushu University, 医学研究院, 助教 (80448422)
Project Period (FY)	2009 – 2010
Keywords	機能脳神経外科学
Research Abstract	64 cases (Transcranial stimulation (TCS) : 29 cases, Direct cortical stimulation (DCS) : 35 cases) were included in this study. With increasing intensity from threshold level until 200 mA, the latency came to plateau, and no "jump" of latency was observed. The difference of latency between TCS and DCS was quite small. These results suggested that the activated area of TCS was almost same as far as the intensity is less than 200mA. The amplitude of MEPs after TCS with 200mA was much higher in the contralateral side compared to the ipsilateral, which suggested that the activated area was not brain stem but subcortex, where the bilateral cortico-spinal tract run distantly. In two cases in which significant deterioration of MEPs occur, postoperative contralateral palsies were observed. The corresponding lesions in these cases were internal capsula, which meant that the activated areas were subcortex which is proximal to the internal capsula. For TCS-MEP monitoring, the best intensity was thought to be the intensity needed for the supramaximal amplitude less than 200mA.