Toward photorealism in endoscopic sinus surgery simulation

Background: Endoscopic sinus surgery (ESS) is the surgical standard treatment for chronic rhinitis/rhinosinusitis and nasal polyposis. There is a reported complication rate of 5-10% associated with this type of surgery. Simulation has been advocated as a means to improve surgical training and minimize the rates of complication and medical error. This study aimed to show how a virtual reality ESS simulator was developed, with particular emphasis on achieving satisfactory photorealism and surgical verisimilitude. Methods: Sinus computed tomography scans were processed to create a triangle-based three-dimensional mesh model; this was incorporated into a spring-damper model of thousands of interconnected nodes, which is allowed to deform in response to user interactions. Dual haptic handpiece devices were programmed to simulate an endoscope and various surgical instruments. Textures and lighting effects were added to the mesh model to provide an accurate representation of the surgical field. Effects such as vasoconstriction in response to "virtual" decongestant were added. Results: The final simulated endoscopic view of the sinuses accurately simulates the moist and glossy appearance of the sinuses. The interactive tissue simulation system enables the user to interactively cut and remove tissue while receiving accurate haptic feedback. A working prototype of the simulator has been developed that leverages recent advances in computer hardware to deliver a realistic user experience, both visually and haptically. Conclusion: This new computer-based training tool for practicing ESS provides a risk-free environment for surgical trainees to practice and develop core skills. The novel use of customized precision force feedback (haptic) devices enables trainees to use movements during training that closely mimic those used during the actual procedure, which we anticipate will improve learning, retention, and recall.