Soft bracing mechanism for minimally invasive cardiac interventions surgery
Embargo Date
2025-01-15
OA Version
Citation
Abstract
In minimally-invasive endovascular procedures, surgeons rely on catheters with uniform stiffness and high aspect ratios to reach an anatomical target. The catheters enter a patient through a small incision (e.g., the femoral or radial artery) and may traverse tens of centimeters through blood vessels before reaching the beating heart intervention surgical site. As such, it can be difficult for surgical tools to maneuver dexterously and apply significant forces from the distal tip of the catheter during procedures (e.g., annuloplasty, coronary sinus lead placement, or catheter ablation for atrial fibrillation). This thesis focuses on the fabrication and design of the bracing mechanism and presents strategies for deployment and integration with other surgical manipulators.
This thesis demonstrates collapsible mechanisms that can deploy from the tip of a catheter under 8 mm in diameter and expand to over 25 mm in diameter to brace against the local anatomy and generate a fixed constraint in the superior vena cava (SVC) for guiding a catheter inside the heart. This mechanism can increase the force transmission in the radial and axial direction, and the temporarily fixed point serves as a local fulcrum from which a surgical tool or robot can maneuver. Additionally, the demonstrated bracing mechanisms are soft enough to interact with the delicate inner walls of the SVC; hollow such that the blood flow pressure drop does not exceed dangerous levels; and collapsible such that they allow deployment from a peripheral access point. These results will help facilitate more effective and efficient minimally-invasive beating heart surgeries, thereby reducing surgeon fatigue and enhancing patient outcomes.