Visual Force Feedback for Hand-Held Microsurgical Instruments

Microsurgery is technically challenging, demanding both rigorous precision under the operating microscope and great care when handling tissue. Applying excessive force can result in irreversible tissue injury, but sufficient force must be exerted to carry out manoeuvres in an efficient manner. Technological advances in hand-held instruments have allowed the integration of force sensing capabilities into surgical tools, resulting in the possibility of force feedback during an operation. This paper presents a novel method of graduated online visual force-feedback for hand-held microsurgical instruments. Unlike existing visual force-feedback techniques, the force information is integrated into the surgical scene by highlighting the area around the point of contact while preserving salient anatomical features. We demonstrate that the proposed technique can be integrated seamlessly with image guidance techniques. Critical anatomy beyond the exposed tissue surface is revealed using an augmented reality overlay when the user is exerting large forces within their proximity. The force information is further used to improve the quality of the augmented reality by displacing the overlay based on the forces exerted. Detailed user studies were performed to assess the efficacy of the proposed method.