Postoperative evaluation of extracranial-intracranial arterial bypass by means of ultrasonic quantitative flow measurement and computed mapping of the electroencephalogram.

As an objective evaluation of extracranial-intracranial (EC/IC) bypass operation, we studied 10 patients with occlusive cerebrovascular disease after EC/IC bypass operation using ultrasonic quantitative flow measurement (UQFM) and the computed mapping of the electroencephalogram (CME). After the operation, to evaluate the efficacy of the bypass operation, we studied all patients by UQFM and CME before and during compression of the superficial temporal artery (STA). In a control series of cases, the change in common carotid blood flow during STA compression was not statistically significant, and the findings of CME were unchanged during STA compression. In the cases with bypass surgery, reduction of the common carotid blood flow during STA compression was obvious and statistically significant (P less than 0.001). Additionally, in 5 of the 10 cases, the CME findings were aggravated during STA compression. Therefore, in these 5 cases the brain with bypass seems functionally dependent upon the bypass flow. It is suggested that the EC/IC bypass is effective at least in these 5 cases. The UQFM and the CME, which are noninvasive and simple, are very useful for postoperative evaluation of EC/IC bypass grafts from a hemodynamic and functional point of view.