A deflectable video camera system for laparoscopic surgery based on shape memory alloy actuators

Area of Science:

• Medical Devices
• Robotics
• Materials Science

Background:

• Laparoscopic instruments lack deflectability, limiting usability in minimally invasive surgery.
• Current flexible-tip devices are often heavy, expensive, and rely on manual controls.
• Shape memory alloy (SMA) actuators present a promising alternative due to their light weight and cost-efficiency.

Purpose of the Study:

• To develop and evaluate a laparoscopic video camera with electronic deflection control using SMA actuators.
• To demonstrate the feasibility of SMA actuators for universal control of endoscopic instruments.
• To investigate the performance and durability of the SMA-actuated camera system.

Main Methods:

• Designed a laparoscopic camera with a two-degree-of-freedom tilt mechanism using a Nitinol joint.
• Utilized an actuator unit with four SMA wires and a specialized tensioning mechanism.
• Characterized system functionality using three assembled units and an automated measurement system.
• Investigated the impact of continuous temperature stimulation on device parameters.

Main Results:

• Achieved deflection angles exceeding 178° per degree of freedom.
• Demonstrated suitable deflection behavior at operating frequencies up to 0.5 Hz.
• Units maintained functionality for over 1200 actuation cycles or 4.4 hours of continuous operation.

Conclusions:

• SMA actuators are feasible for the electrical control of flexible-tip laparoscopic instruments.
• The developed camera system shows promising performance and durability.
• Temperature control presents a key challenge for future development and optimization.