Simulation Method for the Physical Deformation of a ThreeDimensional Soft Body in Augmented RealityBased External Ventricular Drainage

Objectives: Intraoperative navigation reduces the risk of major complications and increases the likelihood of optimal surgi-cal outcomes. This paper presents an augmented reality (AR)-based simulation technique for ventriculostomy that visualizes brain deformations caused by the movements of a surgical instrument in a three-dimensional brain model. This is achieved by utilizing a position-based dynamics (PBD) physical deformation method on a preoperative brain image. Methods: An in-frared camera-based AR surgical environment aligns the real-world space with a virtual space and tracks the surgical instru-ments. For a realistic representation and reduced simulation computation load, a hybrid geometric model is employed, which combines a high-resolution mesh model and a multiresolution tetrahedron model. Collision handling is executed when a col-lision between the brain and surgical instrument is detected. Constraints are used to preserve the properties of the soft body and ensure stable deformation. Results: The experiment was conducted once in a phantom environment and once in an ac-tual surgical environment. The tasks of inserting the surgical instrument into the ventricle using only the navigation informa-tion presented through the smart glasses and verifying the drainage of cerebrospinal fluid were evaluated. These tasks were successfully completed, as indicated by the drainage, and the deformation simulation speed averaged 18.78 fps. Conclusions: This experiment confirmed that the AR-based method for external ventricular drain surgery was beneficial to clinicians.