Firing Redirect Assembly for Surgical Stapler Joint Stability
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Solution Overview
Problem
Existing surgical staplers face challenges in maintaining articulation joint performance under high firing loads, leading to de-articulation issues due to increased forces required for compressing thicker tissues, especially in endocutters with direct push firing systems.
Innovation Solution
The surgical instrument employs a differential drive assembly with an articulation joint comprising movably interfacing annular disc members and elastomeric spacers, coupled with a flexible push coil and cable system to manage articulation and firing forces, ensuring stable operation even at large articulation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a direct push firing system is used to transmit firing loads through the articulation joint, then the firing force can be effectively transmitted to the end effector, but the articulation joint experiences increased reaction forces that lead to de-articulation and joint performance degradation
Solution Approach 1:
The articulation joint is divided into multiple movably interfacing annular disc members that can independently move relative to each other. This segmentation allows the joint to better distribute and manage the reaction forces from the firing system, preventing de-articulation while maintaining effective force transmission to the end effector.
Solution Approach 2:
Elastomeric spacers are introduced between the annular disc members to change the mechanical parameters of the joint. These spacers provide compliance and damping, allowing the joint to absorb reaction forces dynamically while maintaining articulation stability under high firing loads.
2Strength
If the knife encounters thicker tissue requiring high firing forces for compression and cutting, then the cutting capability is improved, but the increased loads generate high reaction forces at the articulation joint causing de-articulation
Solution Approach 1:
The articulation joint transitions from a rigid structure to a dynamic system with movably interfacing annular disc members and elastomeric spacers. This dynamic configuration allows the joint to adapt and maintain stability under varying loads, enabling strong tissue cutting while preventing de-articulation through controlled movement and force distribution.
3Adaptability or versatility
If the end effector is articulated to large angles to facilitate positioning, then the positioning flexibility is improved, but the friction and resistance in the articulation joint increase, affecting operation smoothness
Solution Approach 1:
The elastomeric spacers between the annular disc members provide variable compliance that changes with articulation angle. At larger articulation angles, the spacers deform to accommodate the increased geometry, maintaining smooth operation by reducing friction and resistance while preserving positioning flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively manages high firing loads and maintains articulation joint stability, preventing de-articulation and reducing friction, thereby enhancing the efficiency and reliability of the surgical stapler's operation.
Implementation Method 1
an articulation joint comprising movably interfacing annular disc members and elastomeric spacers
Implementation Method 2
reducing friction, thereby enhancing the efficiency and reliability of the surgical stapler's operation
Data Source
AI summary
An end effector of a surgical instrument may be equipped with a firing redirect assembly including: a firing carrier; a reaction pulley disposed distally from the firing carrier; a firing cable coupled to a distal end of the firing carrier and wrapping around the reaction pulley and extending proximally past the firing carrier; and a reaction cable coupled to and extending between a distal end of the reaction pulley and a proximal end of an end effector of the surgical tool, the end effector including a cartridge jaw and an anvil jaw pivotably connected to the cartridge jaw at a pivot, where a firing load on the firing cable in a proximal direction causes the firing carrier to translate distally and causes the reaction pulley and the reaction cable to translate proximally, thereby assisting with closing the anvil jaw or assisting with stabilizing an articulation joint of the end effector.