C. Barillot, D.R. Haynor, and P. Hellier (Eds.): MICCAI 2004, LNCS 3217, pp. 319–327, 2004. © Springer-Verlag Berlin Heidelberg 2004 A Collaborative Virtual Environment for the Simulation of Temporal Bone Surgery Dan Morris 1 , Christopher Sewell 1 , Nikolas Blevins 2 , Federico Barbagli 1 , and Kenneth Salisbury 1 1 Stanford University, Department of Computer Science 2 Stanford University, Department of Otolaryngology {dmorris, csewell, barbagli, jks}@robotics.stanford.edu, nblevins@stanford.edu Robotics Laboratory Gates Building 1A Stanford CA 94305-9010, USA Abstract. We describe a framework for training-oriented simulation of tempo- ral bone surgery. Bone dissection is simulated visually and haptically, using a hybrid data representation that allows smooth surfaces to be maintained for graphic rendering while volumetric data is used for haptic feedback. Novel sources of feedback are incorporated into the simulation platform, including synthetic drill sounds based on experimental data and simulated monitoring of virtual nerve bundles. Realistic behavior is modeled for a variety of surgical drill burrs, rendering the environment suitable for training low-level drilling skills. The system allows two users to independently observe and manipulate a common model, and allows one user to experience the forces generated by the other’s contact with the bone surface. This permits an instructor to remotely observe a trainee and provide real-time feedback and demonstration. 1 Introduction 1.1 Temporal Bone Surgery Several common otologic surgical procedures – including mastoidectomy, acoustic neuroma resection, and cochlear implantation – involve drilling within the temporal bone to access critical anatomy within the middle ear, inner ear, and skull base. As computer simulation is becoming a more frequently used technique in surgical train- ing and planning, this class of procedures has emerged as a strong candidate for simulation-based learning. The time spent on a procedure in this area is typically dominated by bone removal, which is performed with a series of burrs (rotary drill heads) of varying sizes and surface properties. Larger burrs are generally used for gross bone removal in the early part of a procedure, while smaller burrs are used for finer work in the vicinity of target anatomy. Surgeons employ a variety of strokes and contact techniques to pre- cisely control bone removal while minimizing the risk of vibration and uncontrolled drill motion that could jeopardize critical structures. Drills are generally driven by