The Holographic Human for Surgical Navigation using Microsoft HoloLens

In surgical navigation, to accurately know the position of a surgical instrument in a patient's body is very important. Using transparent smart glasses is very useful for surgical navigation because a surgeon does not need to move his/her line of sight from the operative field. We propose a new application software development method that is able to show a stereoscopic vision of highly precise 3D-CG medical models and surgical instruments using transparent smart glasses for surgical navigation. We used Mixed Reality (MR) which is a concept exceeding Augmented Reality (AR) by using Microsoft HoloLens. In Mixed Reality, persons, places, and objects from our physical and virtual worlds merge together in a blended environment. Unlike competitive models, HoloLens can recognize surrounding with a front-facing cameras and 3D depth sensors. External markers and sensors are not required for surrounding recognition. Once a 3D-CG medical model is placed in a blended environment, it is fixed to the place and does not move on its own. Therefore, we can see a stereoscopic vision of a precise medical model projected into our surrounding such as a holographic human. A holographic human is as if he/she is there, which is a special immersive experience we have never felt before. A holographic human can not only be seen, but also can be moved by user’s hand gestures and interactive manipulation is possible. A holographic human and 3D-CG surgical instrument can be displayed simultaneously in a blended environment. The movement of 3D-CG surgical instruments can be linked with actual surgical instruments in the operation room. In the operation room, the holographic human is superimposed on the actual patient position. Since the positional relationship between the holographic human and surgical instruments is clear because it is overlapping, so it is very useful for surgical navigation. Multiple persons can see one holographic human at the same time using multiple HoloLenses. We developed the holographic human application software for surgical navigation using Unity and Vuforia, which are a development software and a library. A holographic vision of a 3D-CG medical model made from an actual patient’s CT/MRI image data is possible using our application software development method. A user can make the application software within only five minutes by preparing 3D-CG medical model file for instance STL. Therefore, surgeon dentists and clinical staff can make the holographic human content easily by themselves. As a result, the method can be utilized daily for routine medical treatment and education.