INTRODUCTION: Conventional craniofacial surgical planning software lacks intuitive operator interaction and 3D navigation. Recently available augmented reality (AR) headsets have the potential for detailed 3D holographic projections of virtual 3D models, intuitive interaction and navigation, and accurate measurements.
OBJECTIVE: To evaluate the accuracy of linear measurements performed on HoloLens (Microsoft, Seattle, Wash.) in comparison with digital microcaliper towards assessing potential use for surgical planning.
METHODS: Seven adult dry human skulls were selected based on stable occlusion. Stereolithography files were generated from CT imaging data acquired with a default imaging protocol, loaded onto HoloLens. Two researchers performed two repeated linear measurements on 1) skulls with digital microcaliper as an anatomic physical measurement (gold standard) and 2) holograms by selecting two surface points. A subset of measurements that could be measured with digital microcaliper was used. We defined the limits of an agreement as 95% and the agreement between two methods was evaluated using the Bland and Altman analysis.
RESULTS: All HoloLens measurements were completed by easily “gazing” and navigating through complex 3D structures augmented to the virtual operating room. There was no significant bias between two methods used and 95% of the values were within the limits of the agreement.
CONCLUSION: Our results indicate that HoloLens has significant potential for surgical planning including sufficient accuracy for linear measurements. Future studies will include curvilinear measurements, formal usability evaluation and augmentation of 3D holographic planning results for intraoperative use.