Towards a Tendon-Driven Robotically Steerable Guidewire with a Retractable Distal Balloon

Minimally invasive endovascular and transcather procedures frequently involve delivering tools to the surgical site via a guidewire. Even when made steerable, the guidewire tip has the potential to cause tissue damage while traversing the vasculature and the connected organs. In this work, a methodology is introduced to integrate a balloon onto a tendon-driven robotically steerable guidewire to cushion the contact with tissue during traversal, stabilize within the vasculature once the guidewire has passed the surgical site, and arrest bloodflow to prevent distal embolization. A model is presented for the effects of a pressurized fluid channel on the curvature of the tendon-driven joint during bending, and also for the inflation of the hydraulic element on the tip of the guidewire. The balloon is fabricated via injection molding and a hydraulic pump is integrated with the actuation system to facilitate distal balloon inflation and deflation. The accuracy of the bending and inflation models was experimentally verified to demonstrate the validity of the approach with steerable balloon guidewire systems. The guidewire was tested in a phantom vasculature model under pulsatile flow to demonstrate traversal, inflation, and flow arrest in pseudo-physiological conditions.