A novel methodology for usability assesment of rheological soft tissue models

The task to distinguish between soft tissues by testing their mechanical properties is often referred to as the primary cognitive role of haptic devices. It is a common view that today's surgical simulators that are using haptic interfaces should rely on simple mechanical models of soft tissues, instead of complex, parameterized finite element models, thus enhancing real-time operation and focusing on the most representative mechanical effects. This paper proposes a user-trial validation method for tissue models and their polytopic representation by creating an experimental framework for soft tissue characterization, using the da Vinci Research Kit. The characterization methdodology relies on haptic feedback from the manipulated real tissue, extending the functionality of surgical simulators using virtual tissue models created by the previously proposed soft tissue modeling method. Results showed that the tissue model represents the tissue behavior sufficiently well for use in haptic simulators, based on user experience. Furthermore, it was concluded that silicon phantoms can mimic the behavior of real tissues in various surgical scenarios, especially when using teleoperation manipulation.