Prospective Comparison of Intraoperative Vascular Monitoring Technologies During Cerebral Aneurysm Surgery

BACKGROUND: Microscope integrated intraoperative near-infrared indocyanine green angiography (ICGA) provides assessment of the cerebral vasculature in the operating field. OBJECTIVE: To prospectively compare the value of ICGA-derived information during cerebral aneurysm surgery with data simultaneously generated from other intraoperative monitoring and vascular imaging techniques. METHODS: Data from 104 patients with 123 cerebral aneurysms who were operated on were prospectively recorded. Results of intraoperative vascular monitoring and descriptions of how this information influenced intraoperative decision making were analyzed. RESULTS: Clip repositioning was necessary in 30 of 123 aneurysms (24.4%) treated. Parent artery occlusion was documented by microvascular Doppler ultrasound in 4 aneurysms. ICGA disclosed parent artery stenoses not detected by sonography in 7 cases. Neuroendoscopy was used in 13 cases of midline aneurysms to confirm perforator patency after clipping, and disclosed aneurysm misclipping undetected by ICGA and digital subtraction angiography in 1 aneurysm. The information from DSA and ICGA corresponded in 120 of 123 aneurysms operated on (97.5 %). In 1 patient, ICGA underestimated a relevant parent artery stenosis detected by digital subtraction angiography. In 2 patients with relevant aneurysmal misclipping, digital subtraction angiography and ICGA led to conflicting results that could be clarified only when both methods were used and interpreted together. CONCLUSION: The intraoperative monitoring and vascular imaging methods compared were complementary rather than competitive in nature. None of the devices used were absolutely reliable when used as a stand-alone method. Correct intraoperative assessment of aneurysm occlusion, perforating artery patency, and parent artery reconstruction was possible in all patients when these techniques were used in combination.