Abstract
In order to evaluate cerebral circulatory reserve, carotid artery compression of the contralateral side of main vascular lesion was performed under electroencephalographic and electrocardiographic control in 20 cases of STA-MCA anastomosis. Superficial temporal artery compression on the side of the operation was also carried out. EEG slowing was noted within 20 seconds on the compressed side in half of the cases when the carotid artery was compressed.
From the standpoint of cerebral circulatory reserve, these results were interpreted as follows: 1) Negative compression test gives no imminent decrease of the circulatory reserve. 2) Preoperatively positive responce indicates that the reserve through the collateral is not adequate and, therefore, good indication for the surgery. 3) In cases of significantly built-up collateral bypass by the anastomosis, slow wave activity was not provocated on the side of anastomosis (1 case), and time interval between digital compression and EEG changes delayed (2 cases). These evidences indicate that the reserve has been increased on the operated side in these cases. 4) If the evoked EEG abnormality is not altered postoperatively, blood flow via anastomosed bypass is suggested to be insufficient yet. 5) Focal EEG changes were evoked in 3 cases by the compression of the anastomosed STA, which suggests that effective blood flow in the area is dependent on the anastomosed STA.
These findings are well correlated with the results of angiographic study.
