Force-based flexible path plans for robotic electrode insertion

Rapidly deployable surgical robots pose minimal interruption to surgical workflow and require minimal setup time and equipment to support deployment. This paper explores the concept of rapid deployment through the use of in-vivo sensory information to adapt a pre-operative surgical plan and to increase robustness against registration and misalignment errors during robot deployment. Robotic insertion of cochlear implant electrode arrays is presented as a benchmark application demonstrating this concept. Two key ideas are presented within the context of this application: First, a hybrid position and admittance controller is used to define an insertion path plan that is modified based on in-vivo force measurements in order to reduce sensitivity to misalignment errors. Secondly, a new concept allowing the use of force cues to determine the onset of advance-off stylet electrode array insertion is presented. The new controller is tested with electrode insertions in both plastic models and human cadaveric specimens. The experiments show that insertion forces may be maintained or reduced compared to preplanned trajectories relying solely on the initial registration.