血行再建術を用いた脳動脈瘤治療におけるBalloon test occlusionの有用性と問題点  [in Japanese] Balloon Test Occlusion as a Preoperative Evaluation for Cerebral Aneurysms Treated with Bypass Surgery  [in Japanese]

For the treatment of patients with complex internal carotid artery (ICA) aneurysms, it may be necessary to occlude the parent artery following a bypass surgery. The bypass surgery may be low or high flow bypass, but selection criteria have not been established. We retrospectively analyzed our method using preoperative balloon test occlusion (BTO). Thirty-five patients with ICA aneurysms, 15 ruptured and 20 unruptured, were treated with parent artery occlusion with bypass surgery. Preoperative BTO was performed in 27 cases (all unruptured and 7 ruptured, chronic stage cases). When ischemic symptoms occurred during BTO, high flow bypass was performed followed by parent artery occlusion. Otherwise, single-photon emission computed tomographic findings during BTO were used for the bypass selection. If ipsilateral residual blood flow was 70-75% or less of the contralateral hemisphere, high flow bypass was chosen and if between 70-75% and 90%, superficial temporal artery-middle cerebral artery (STA-MCA) bypass was employed. In the acute stage of 8 ruptured cases, BTO was not performed and bypass selection was made according to angiographic findings only. After completion of the bypass, ipsilateral ICA occlusion (ICO) was performed either by direct or intravascular technique. The site of ICO was determined to completely block the blood flow into the aneurysm considering both conventional angiography and BTO findings. A total of 15 STA-MCA and 20 high flow bypasses were performed followed by ICO. There was no mortality or morbidity in unruptured cases. In ruptured cases, there were 3 complications related to surgical procedure such as perforator injury, but no patients showed insufficient ipsilateral cerebral blood flow postoperatively. One asymptomatic cerebral infarction developed due to BTO. In 5 cases, petrous portion collateral flow from external to internal carotid artery was seen, and the ICO was performed above the collateral using intravascular embolization. In patients with complex ICA aneurysms to be treated with bypass surgery and ICO, BTO may provide a reliable tool to determine the bypass method and the site of ICO.