Design, Fabrication, and Testing of a Needle-Sized Wrist for Surgical Instruments

Area of Science:

• Medical Devices
• Robotics
• Materials Science

Background:

• Minimally invasive surgery requires instruments with enhanced dexterity and maneuverability.
• Existing surgical tools often lack the necessary articulation for complex anatomical regions.

Purpose of the Study:

• To present a novel miniature wrist for integration into needle-sized surgical instruments.
• To demonstrate high distal curvature and tip-first bending capabilities.
• To validate the design's fabrication, scalability, and performance in a surgical context.

Main Methods:

• Fabrication of a miniature wrist using a nitinol tube with asymmetric cutouts.
• Actuation of the wrist via a single tendon.
• Derivation and experimental validation of kinematic and static models.
• Experimental investigation of fatigue life and tip-first bending.
• Integration with a concentric tube robot for an endonasal surgical scenario.

Main Results:

• Successful development of a miniature wrist capable of high distal curvature.
• Experimental validation of kinematic and static models.
• Demonstration of straightforward fabrication and design scalability.
• Positive results in fatigue life testing and tip-first bending.
• Feasible practical application in an endonasal surgical simulation.

Conclusions:

• The developed miniature wrist offers a scalable and easily fabricated solution for enhancing surgical instrument dexterity.
• The design enables precise control and high curvature, suitable for needle-sized instruments in minimally invasive procedures.
• The wrist shows promise for improving surgical outcomes in complex anatomical sites.