Development of a Miniaturized 6-DoF Surgical Instrument with a 4-mm Elbow and 3-mm Wrist for Transoral Robotic Surgery
Cate Balasubramanian, Sunny Zhang, Teng Li, Paul Hoseok Kang, Ali A. Nazari, Thomas Looi, Dale Podolsky
AI summary
Problem
Current transoral robotic surgery platforms are too large or rigid for confined pediatric oropharyngeal workspaces, leading to tool collisions, limited reach, and inadequate dexterity for complex tasks.
Approach
The team developed a cable-driven 6-DoF instrument featuring a novel pinless sandwich link architecture for high-density tendon routing, controlled by an empirical real-time compensation algorithm to decouple joint motion.
Key results
- Novel pinless sandwich link architecture enabling 4-mm diameter with eight routed tendons
- Empirical kinematic compensation reducing joint coupling by over 80% for pitch and yaw
- Successful macro-micro teleoperation integration with a Franka Research 3 manipulator
- Workspace analysis confirming high distal dexterity and collision avoidance in pediatric oropharyngeal regions
Why it matters
Establishes the first hardware foundation for dexterity-intensive pediatric transoral surgery, enabling precise suturing and dissection in previously inaccessible confined spaces.
Abstract
Current platforms for Transoral Robotic Surgery (TORS) are suboptimal for confined oropharyngeal workspaces, particularly in pediatric applications. To address this, we present the design and characterization of a novel cable- driven robotic instrument providing 6 degrees-of-freedom (DoF)—shaft roll, elbow pitch/yaw, wrist pitch/yaw, and grip—for dexterous manipulation. The system integrates a miniaturized 4-mm proximal elbow with a previously developed 3-mm distal wrist. This architecture is enabled by a novel “sandwich” link architecture that facilitates high-density cable routing through the joint’s center plane, providing a compact, rigid alternative to traditional pin-jointed designs. Experimen- tal validation identified significant kinematic coupling between in-plane joint pairs. An empirical real-time compensation strat- egy reduced this coupling rate by 82.9% for pitch and 80.8% for yaw. Workspace analysis confirmed the proximal elbow enables high distal dexterity at regions critical for complex surgical tasks. Integration with a Franka Research 3 manipulator enabled fully coordinated macro-micro teleoperation, providing a pilot demonstration for TORS workflows. This represents the first demonstration of a 4-mm elbow-3mm wrist mechanism for TORS, providing the hardware foundation necessary for future evaluation of dexterity-intensive tasks, including suturing and dissection.