P128. Holographic superimposition of spine model

<h3>BACKGROUND CONTEXT</h3> The current surgical practices are undergoing evolutionary adoption of mixed reality-based technologies. Augmented reality (AR) comes into the field as a possible way of augmentation of the real anatomical structure during surgery without any attention drift of the surgeon. Operative error is a major concern during complex surgical procedures and disruption of the surgeon's attention potentiates toward it. Pedicle screw placement procedure in surgical fusion surgery is a complex procedure in nature and current conventional practices disrupt surgeons' attention. Implementation of head-mounted display based augmented reality platform, HoloLens, into the procedure increases the accuracy of fixation of pedicle screw where it depends on the use of the conventional method of recognition of the target object and of projection of holographic images into the surgeon's operative field which limits the required dynamic and interactive nature of the procedure. <h3>PURPOSE</h3> This paper aims to develop and validate a novel method of recognition of the target object and overlaying hologram into the target object of the field of spine surgery procedure with respecting the spatial relationship of the geometry of a reference tool in the surgical field. There are two tasks to achieve this objective. First, the development of a novel method of holographic projection for spinal surgery. Second, to examine the accuracy of the projection of the hologram into the target object with or without movement of the target spine model and patient reference model. <h3>STUDY DESIGN/SETTING</h3> The study has been divided into 1) development and 2) validation arms. The holographic model has been built with Unity Editor, Mixed Reality Tool Kit, and C# programming languages to define the behavior of the model. The target structure of the complex geometry of the spine model and the patient reference model has been designed and integrated into the game engine. The holographic behavior of both models has been designed with the script based on C# programming languages. The experiment has been designed to test the accuracy of the holographic superimposition. So, it has been experimented in laboratory benchwork condition. <h3>OUTCOME MEASURES</h3> The model will recognize the target patient reference model for spine surgery. <h3>METHODS</h3> The experiment has been conducted to test the target position of anatomical landmark structures with the help of virtually calibrated softwares. The mixed reality captures of the recognition of patient reference model has been taken and analyzed with IC Measure 2 software. <h3>RESULTS</h3> The HoloLens recognizes and projects holograms into the complex spinal geometry maintaining the spatial relationship of the simple geometry of the patient reference model with or without movement. It limits the maximum positional error at 1.31 +/- 3.57 mm, the form error rate at 0.022 mm +/- 0.17 mm and rotational error at0.89°+/- 1.65° without any statistically significant differences of error rate among all the axes. <h3>CONCLUSIONS</h3> This study has established a novel model to create a holographic projection of complex geometry and stabilization of the hologram with the dynamic procedure. So, this novel model would create the first way of dynamic augmentation of interactive surgical guidance system into the operative field of spine surgery procedure even in the spaces. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.