経頭蓋超音波カラードプラガイド下Ｍａｔａｓテスト 頚動脈切除・再建術の適応決定

Abstract

Carotid artery involvement in head and neck tumor is a great concern to surgeons because of the unpredictable effects of its resection. For the investigation of brain collateral circulation, color Doppler guided Matas' test has been performed to examine blood flow in the middle cerebral artery (MCA) and internal carotid artery (ICA). SSA-270A convex (3.75MHz) and linear (3.75MHz, 2.5MHz) array probes (Toshiba Co., Ltd.) were used for this investigation. A temporary occlusion test (60 sec) was performed on the common carotid artery (CCA) in thirty patients who were scheduled to undergo radical neck dissection. The blood flow velocity of MCA during Matas' test was recorded. Then relative flow (percent blood flow before the test) of MCA during the 60 sec Matas' test was measured. The relative mean flow was 72% with a standard deviation of 15%. The results of thirty patients were classified into four groups according to the relative flow of MCA after 60 sec occlusion of the common carotid artery: Group A, over 87% (three cases); Group B, 86-72% (twelve cases); Group C, 71-57% (twelve cases); Group D, under 56% (three cases). Brain collateral circulation (BCC) of the Group A patients was considered to be excellent, and therefore reconstructive vascular surgery (RVS) was not necessarily indicated. In Group B patients (fair) and Group C patients (slightly poor) further investigation of BCC, i.e., Balloon Matas' test (occlusion of CCA and ICA), SPECT and brain angiography, was considered to be necessary. In Group D patients (poor) RVS was inevitable if either CCA or ICA had to be resected. Important information is provided by this noninvasive examination to predict the risk of carotid resection. This test seems to be useful to determine whether or not RVS is indicated.