The Usefulness of a Hybrid Operating Room for the Surgical Flow Alteration Treatment of a Large Middle Cerebral Artery Aneurysm: A Case Report

There are certain cerebral aneurysms, such as large, giant, thrombosed, or fusiform, that are unsuitable for clipping or coil embolization. The flow alteration treatment is considered suitable for these aneurysms. We report a case of a large middle cerebral artery (MCA) aneurysm that was successfully treated by flow alteration in a hybrid operating room (OR). The patient was a 37-year-old woman who was incidentally diagnosed with a right MCA M1 proximal unruptured aneurysm. Digital subtraction angiogram (DSA) on admission revealed an irregularly shaped M1 aneurysm with branching M1 perforators adjacent to an aneurysmal neck. Firstly, we tried to perform direct clipping; however, it was impossible to do so unless M1 perforators were sacrificed. Secondly, we planned the flow alteration treatment for this aneurysm. In a hybrid OR, we performed a right superficial temporal artery (STA)-MCA bypass and an EC-IC high-flow bypass with a saphenous vein graft followed by right neck internal carotid artery (ICA) ligation. According to the findings of the intraoperative DSA, the depiction of an aneurysm was more obvious via the posterior communicating artery (Pcom) by a left vertebral angiogram (VAG) than via the anterior communicating artery (Acom) by a left internal carotid angiogram (ICAG). Therefore, we decided to obliterate the Pcom by a Sugita straight clip. Finally, we confirmed the acceptable reduction in flow into the aneurysm by intraoperative DSA. In a postoperative course, the aneurysm was visualized by magnetic resonance imaging (MRI) and DSA and was seen to have gradually reduced. The patient was discharged without any deficit 25 days after a second operation. A DSA at 8 months after the second operation demonstrated the complete obliteration of the aneurysm. For the flow alteration treatment, it is important to consider the flow dynamics through an aneurysm from multiple blood vessels during the operation. A hybrid OR can facilitate the provision of a safe and clean location to perform intraoperative multi-vessel DSA. Thus, a hybrid OR is very useful for flow alteration treatment of complicated cerebral aneurysms.