Can Coffee Improve Surgical Robot Accuracy
Transnasal skull base and sinus surgery is often assisted via image guidance systems (e.g. the Brainlab Kolibri [1] Fig. 1) which show the real time locations of surgical instruments with respect to the 3D map provided by preoperative volumetric medical images. Image guidance systems often employ optical tracking to measure in real time the locations of both surgical instruments and the patient's head. The accuracy of these systems relies on the rigid coupling between optical tracking markers and the patient. However, the markers are often attached to the patient using an elastic headband that can shift if bumped during use [2] In this paper, we propose the use of both layer jamming and granular jamming to improve the accuracy of image guided robotic transnasal sinus and skull base surgery. Granular jamming involves drawing a vacuum on a bag filled with granules (e.g. coffee grounds) [3] Layer jamming involves drawing a vacuum on a bag filled with thin layers of material, to increase the normal force between them and thus prevent them from sliding over one another [4] We use these technologies to securely and non invasively attach optical tracking markers to the patient, which enables accurate registration of preoperative medical images to guide surgical robotic systems, or even manually operated instruments. The prototype described in this paper extends our prior work in which granular jamming alone was used with a plastic frame [2] Here, we use layer jamming in conjunction with granular jamming to create a headband that conforms to the patient's head, becoming rigid when a vacuum is drawn. An example of where this would be useful is in robotassisted drilling. Drilling is often required as a first step in transnasal skull base and sinus surgeries to access the surgical site. It has been previously shown that collaborative human robot systems (in which both the surgeon and the robot hold the drill simultaneously) can assist the surgeon [5] by enforcing virtual fixtures (see [6] for a review) around sensitive anatomy. Another example where registered images and virtual boundaries can be useful is in pituitary surgery, where they have been proposed as a means to prevent damage to the optic nerves and carotid arteries in manual [7] and robotic [8] surgical approaches.