Surgical Device Actuation Wire Decoupling Mechanism
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Solution Overview
Problem
Current laparoscopic and endoscopic surgical devices face challenges in controlling the movement of their working ends due to size constraints and the interference of control motions with the flexibility of the shaft, leading to unintended articulation or actuation of the end effector, and lack suitable feedback for surgeons.
Innovation Solution
The implementation of a surgical device with a flexible elongate shaft and a three-bar linkage mechanism that allows the end effector to be angularly oriented relative to the shaft, using an actuation wire decoupled from the articulation mechanism to isolate actuation from articulation, enabling precise control and reduced force requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control motions are transferred through the shaft as longitudinal translations, then the controls can be implemented, but the flexibility of the shaft is interfered with and unintended articulation occurs
Solution Approach 1:
The control system is segmented into separate functional components: articulation control and actuation control. The articulation mechanism uses a four-bar linkage with articulation links that can pivot independently, while actuation is handled separately by the actuation wire. This segmentation prevents control motions from interfering with shaft flexibility.
Solution Approach 2:
The articulation mechanism acts as an intermediary between the control inputs and the end effector. The four-bar linkage with articulation links and pivot joints translates control motions into precise angular orientations without requiring longitudinal translation through the flexible shaft, thus preserving shaft flexibility while enabling control.
2Ease of operation
If force is applied to actuate the end effector, then the end effector can be activated, but unintended articulation or hinging of the end effector occurs
Solution Approach 1:
The actuation function is extracted from the articulation mechanism. The actuation wire is routed through the articulation mechanism but is decoupled from it, allowing the end effector to be actuated independently without causing articulation. This separation eliminates unintended hinging while maintaining actuation capability.
Solution Approach 2:
The articulation mechanism is designed with dynamic characteristics where the actuation wire passes through guides and pulleys that allow it to move independently of the articulation links. This dynamic design ensures that actuation forces do not translate into articulation motions, preventing unintended hinging.
3Ease of operation
If the force-to-fire is lowered to a level that all surgeons can handle, then the device becomes more usable, but electrical motors are required which eliminate user feedback
Solution Approach 1:
The patent replaces electrical motor systems with a purely mechanical actuation system using an actuation wire and four-bar linkage. This mechanical system provides natural tactile feedback to the surgeon through the control mechanisms while requiring minimal force to operate, eliminating the need for motors and preserving user feedback.
Solution Approach 2:
The mechanical system is designed to be self-regulating, where the forces required for actuation naturally fall within a range suitable for surgical use. The four-bar linkage and articulation mechanism provide mechanical advantage that reduces the force-to-fire to manageable levels without requiring external power sources or motors.
Data Source
AI summary
Methods and devices are provided for controlling movement of a working end of a surgical device, and in particular for performing various surgical procedures using an instrument having an end effector that can be articulated relative to an elongate shaft of the device. A decoupling member can isolate the actuation of the end effector from the articulation of the end effector. In certain embodiments, the end effector can also optionally rotate relative to the elongate shaft of the device, and/or the shaft can rotate relative to a handle of the device.