1387 Optimizing the Workflow of STA Mapping in EC-IC Bypass Surgery Using Mixed Reality

INTRODUCTION: Mixed reality (MR) is a developing field within neurosurgery. Doppler ultrasound is the conventional technique for mapping the superficial temporal artery (STA); however, MR provides an opportunity to optimally map the STA using a patient-specific anatomic overlay. METHODS: Five patients undergoing STA-MCA bypass surgery for Moyamoya between January and April 2024 were enrolled. Pre-operative CT-angiograms were registered and superimposed onto the patient using SurgicalAR(Medivis,New York,NY). Six standardized anatomic fiducial points were chosen for intra-operative registration: nasion, tip of the nose, ipsilateral medial canthus, ipsilateral lateral canthus, ipsilateral pinna, and ipsilateral tragus. Five uniformly spaced points were annotated along the parietal branch of the STA using both MR and Doppler techniques. Mapping time was compared using the Mann-Whitney U-test. Using a standardized line thickness of 5mm per map, the percentage of map overlap was evaluated using computer vision (OpenCV, Python). RESULTS: MR mapping of the STA was significantly faster than Doppler mapping(11.4±1.2 vs. 65.9±20.9 seconds;p=0.009). Even when considering the time to register the MR overlay, the overall time for MR mapping was similar to Doppler(94.0±37.8 vs. 65.9±20.9 seconds;p=0.32). MR mapping of the distal points on the STA was faster than Doppler(point four: 2.1±0.45 vs. 22.2±13.3 seconds;p=0.037);(point five: 2.7±0.98 vs. 18.3±7.8 seconds;p=0.01). Overall, there was comparable accuracy between the MR and Doppler maps with an average overlap of 56%(range:22-90%). The average radial deviation between MR-Doppler maps was 4.2mm(range:0.86-8.4mm). CONCLUSIONS: This is the first study to evaluate MR against standard Doppler techniques for STA mapping in STA-MCA bypass procedures. We demonstrate that MR can map the STA faster while producing a similar map to the traditional Doppler technique, suggesting that the incision based on either map is unlikely to change.