Simulation of the surgical procedure. a: Setup for pre-operative simulation. The virtual 3D model was controlled with a keyboard and a 3D tactile mouse. Rotation and opacity control of the virtual 3D model were controlled by a keyboard. A 3D tactile mouse was used to manipulate surgical instruments such as a scalpel, forceps, and scissors. b: Operating room setup including the simulation system. The same system was brought to the operating room and connected to a large external monitor located at the patient’s head to allow intraoperative visualization.