Tactile guidance in multimodal computer navigated surgery

Computer-aided surgery (CAS) is currently a well-accepted means of supporting the surgeon. Primarily, the development of imaging technologies like ´ computer tomography (CT) or magnetic resonance imaging (MRI) is responsible for the entrance of CAS in clinical practice. The design of novel pose measurement systems has abetted this entrance, and the imaging technologies offer many advantages such as the possibility of a 3-D reconstruction images of patients and preoperative planning. The problem was with correlating this image data with the actual body of the patient. The development of navigation systems with integrated pose measurement systems solved this problem. These systems are able to detect special localizers that consist of at least three markers, like active LEDs or a passive high contrast pattern, to determine a coordinate system. The localizers are fixed at the patient, and the surgical instruments and can be used to correlate the image data with the patient´s body. Navigation systems can show the relative situation between instruments and the patient. They provide visibility on a screen during poor or no visibility in reality, as during endoscopic surgery like functional endoscopic sinus surgery (FESS). Tactile displays use the sense of touch for information presentation.The concept of the tactile display is based on the assumption that the position of the human hand can be guided by tactile signals.