HoloLens-Based Vascular Localization System: Precision Evaluation Study With a Three-Dimensional Printed Model

Background: Vascular localization is crucial for perforator flap transfer. Augmented reality offers a novel method to seamlessly combine real information with virtual objects created by computed tomographic angiography to help the surgeon "see through" the skin and precisely localize the perforator. The head-mounted display augmented reality system HoloLens (Microsoft) could facilitate augmented reality based perforator localization for a more convenient and safe procedure. Objective: The aim of this study was to evaluate the precision of the HoloLens-based vascular localization system, as the most important performance indicator of a new localization system. Methods: The precision of the HoloLens-based vascular localization system was tested in a simulated operating room under different conditions with a three-dimensional (3D) printed model. The coordinates of five pairs of points on the vascular map that could be easily identified on the 3D printed model and virtual model were detected by a probe, and the distance between the corresponding points was calculated as the navigation error. Results: The mean errors were determined under different conditions, with a minimum error of 1.35 mm (SD 0.43) and maximum error of 3.18 mm (SD 1.32), which were within the clinically acceptable range. There were no significant differences in the errors obtained under different visual angles, different light intensities, or different states (static or motion). However, the error was larger when tested with light compared with that tested without light. Conclusions: This precision evaluation demonstrated that the HoloLens system can precisely localize the perforator and potentially help the surgeon accomplish the operation. The authors recommend using HoloLens-based surgical navigation without light.