A Continuum Robotic Cannula with Tip Following Capability and Distal Dexterity for Intracerebral Hemorrhage Evacuation.

OBJECTIVE:This paper aims to investigate a new continuum robot design and its motion implementation methods appropriate for a minimally invasive intracerebral hemorrhage (ICH) evacuation.METHODS:We propose a continuum robotic cannula, consisting of a precurved body and a 2-degree-of-freedom (DoF) flexible tip, monolithically fabricated. Kinematic model with cable elongation model, and a dedicated design optimization and motion planning algorithm were developed to enable the follow-the-leader (FTL) motion of the cannula. A task-dependent Jacobian-based closed loop control was also designed to track the cannula motion during the insertion and its independent tip motion.RESULTS:Comprehensive experiments were conducted to verify the kinematic model and submillimeter motion coupling between the cannula precurved body and its flexible tip. The cannula was also capable of achieving FTL motion within around 2.5 mm shape deviation and control performance within submillimeter errors. It was finally demonstrated to be capable of the nonlinear insertion and tip manipulation in the brain phantom.CONCLUSION:The new cannula design, together with the proposed algorithms, provides the unique ability to access ICH in a nonlinear trajectory and dexterous tip motion.SIGNIFICANCE:These motion capabilities of the robot in such a slender form factor will lead to more complete ICH evacuation and reduced trauma to the healthy brain tissues.