Microsurgical Clipping of Intracranial Aneurysms Assisted by Neurophysiological Monitoring, Microvascular Flow Probe, and ICG-VA: Outcomes and Intraoperative Data on a Multimodal Strategy.

Objective: The aim of this study is to report data on a multimodal monitoring strategy based on the intraoperative use of neurophysiological monitoring, flowmetry by microflow probe, and intraoperative indocyanine green video angiography (ICG-VA) during microsurgical clipping of intracranial aneurysms.

Methods: This retrospective analysis was performed on 85 consecutive patients undergoing clipping of 96 intracranial aneurysms with the present monitoring strategy. Patient outcomes were evaluated by assessing rate of aneurysm exclusion and postoperative occurrence of ischemic injury. Intraoperative data for the strategy in addition to changes in each monitoring technique depending on aneurysm features were reported.

Results: Complete aneurysm exclusion was achieved in 98.9% of cases. Postoperative symptomatic ischemic injury was recorded in 2.08% aneurysms. Clip repositioning occurred in 40.6% of cases: because of motor evoked potential (MEP) decrease in 9.3%, flowmetry in 22.91%, and ICG-VA in 8.3% of treated aneurysms (1.05% after ICG injection, 7.4% after the squeezing maneuver). The role of each technique differed according to aneurysm features; flowmetry alterations occurred more frequently in distal than in proximal aneurysms (P = 0.0001) and in atherosclerotic aneurysms (P = 0.0001). MEP impairment occurred more often in proximal aneurysms (P < 0.05). ICG-VA disclosed remnant aneurysms mainly in atherosclerotic aneurysms (P < 0.05); only one false negative remnant neck was recorded with a negative predictive value of 98.8%.

Conclusions: Microsurgical clipping assisted by a multimodal monitoring strategy achieved a high rate of aneurysm exclusion with low morbidity in our series. Our data show that the 3 techniques used in our strategy were complementary and that a monitoring strategy can be tailored to aneurysm features.