E-196 The risk of ischemia in preventive temporary artery occlusion of the contralateral anterior cerebral artery during microsurgical clipping of ACOM aneurysms

Abstract

such as traditional angiographic monitors, holograms, virtual or augmented reality models or 3D printed models. Users are able to experience realistic 3D virtual elements with augmented depth perception and binocular field of view. Newer technology has now allowed for interaction with 3D objects within these virtual environments through the use of hand gestures or hand controllers. The authors describe our preliminary experience with MxR as an adjunct tool to traditional angiographic imaging in the preprocedural workup of patients with complex aneurysms using a novel spatial computer, the Magic Leap One device (Magic Leap, Inc Plantation, Florida) which uses a virtual retinal display, which superimposes 3D computer-generated imagery over real world objects, by projecting a digital light field into the user's eye. Materials and Methods Tomographic Angiographic (DynaCT) data was imported and segmented to create 3D meshes of the intracranial vasculature. The 3D meshes were then projected into MxR space, allowing the operator to inspect the vasculature using a MxR headset (Magic Leap) as well as interact with the aneurysm and adjacent vessels (handling, rotation, magnification, and sectioning) using hand gestures or hand controllers. Results 3D segmentation of a complex aneurysms was successfully performed and projected into MxR. Conventional and MxR visualization modes were equally effective in identifying and classifying the pathology. MxR visualization allowed the operators to manipulate the dataset to achieve a greater understanding of the anatomy of the parent vessel, the angioarchitecture of the aneurysm, and the surface contours of all visualized structures. Conclusion This preliminary study demonstrates the feasibility of utilizing MxR for preprocedural evaluation in patients with anatomically complex neurovascular disorders. This novel visualization approach may serve as a valuable adjunct tool in deciding patient-specific management, including decisions on prognostication and open surgical and endovascular treatment options.

Commentary: The Importance of the Temporary Clip Removal Phase on Exposure to Hypoxia: On-Line Measurement of Temporal Lobe Oxygen Levels During Surgery for Middle Cerebral Artery Aneurysms

“…Derived from the findings of this study, as well as from the current literature on TAO, we propose the following TAO recommendations:Avoid TAO whenever possible.Although the tolerability of TAO is very likely highly variable from patient to patient, TAO seems to be safe up to 10 to 20 minutes. 5-7,9,11,12 A single TAO episode is preferable over multiple TAO events.If multiple TAO events are required, a recovery period of 3 to 4 minutes should be allowed in between. 1 …”

“…Although the tolerability of TAO is very likely highly variable from patient to patient, TAO seems to be safe up to 10 to 20 minutes. 5-7,9,11,12…”

“…2-4 In addition, there is even more disagreement regarding permissive TAO times before permanent ischemic damage occurs. 5-11…”

“…[2][3][4] In addition, there is even more disagreement regarding permissive TAO times before permanent ischemic damage occurs. [5][6][7][8][9][10][11] One of the reasons for the controversy around permissive times and potentially harmful effects of TAO can be attributed to the great variety of methods used in previous studies. Most studies recorded TAO times and correlated them with postoperative ischemic lesions and clinical outcomes.…”

“…Most studies recorded TAO times and correlated them with postoperative ischemic lesions and clinical outcomes. [5][6][7]9,11 Other studies attempted to implement methods of real-time intraoperative measurements to detect pathological changes during TAO. The most common method in this context is intraoperative neuromonitoring with motor-evoked potentials and somatosensoryevoked potentials to determine permissive TAO times.…”