Surgical Stapler Firing Bar Stability via Flexible Support
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Solution Overview
Problem
Existing surgical stapling instruments with articulating end effectors face challenges in controlling firing bars through the articulation joint, leading to potential buckling and inconsistent performance, especially when articulated or not, requiring enhanced support and stability to ensure effective tissue severing.
Innovation Solution
A medical device with a laterally translating articulation mechanism that includes a clevis, adapter sleeve, and a lateral translation device with castellated connectors and biasing devices to maintain alignment and stability of the firing bar, allowing for precise articulation and consistent tissue cutting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the end effector is longitudinally spaced away from the shaft to allow articulation movement, then the articulation flexibility is improved, but the firing bar becomes unsupported and may buckle under longitudinal firing loads
Solution Approach 1:
A flexible support member is introduced as an intermediary element between the shaft and end effector. This member extends through the articulation joint and provides continuous support to the firing bar while allowing the end effector to articulate freely. The flexible support member acts as a mediator that transmits firing forces without restricting articulation movement.
Solution Approach 2:
The support structure uses a flexible support member that can bend and curve as the end effector articulates. This flexible member maintains structural integrity under firing loads while accommodating the dynamic movement of the articulation joint, preventing buckling without constraining articulation flexibility.
2Reliability
If rigid support structures are used to prevent firing bar buckling, then firing bar stability is improved, but the articulation joint becomes constrained and loses flexibility
Solution Approach 1:
The patent employs a flexible support member instead of rigid support structures. This flexible member can curve and bend to accommodate articulation movement while maintaining sufficient stiffness to prevent firing bar buckling under load, thus resolving the contradiction between stability and flexibility.
Solution Approach 2:
The support structure is designed to be dynamic rather than static. The flexible support member changes its configuration as the end effector articulates, adapting its shape to provide continuous support while allowing full range of motion. This dynamic adaptation maintains both stability and flexibility.
3Reliability
If the firing bar is made more rigid to prevent buckling during firing, then firing reliability is improved, but the instrument requires more force to articulate and operate
Solution Approach 1:
The flexible support member provides distributed support along the firing bar's path, preventing buckling with minimal resistance to articulation movement. This approach maintains firing reliability while requiring less force to articulate compared to a fully rigid support structure.
Solution Approach 2:
The flexible support member dynamically adapts to articulation movements, providing support only when needed (under firing loads) while offering minimal resistance during articulation. This dynamic behavior maintains firing reliability without increasing operational force requirements.
Data Source
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AI summary
A medical device comprises a control handle (2) having a stapling actuator (3), an articulation joint actuator (4) and a body through which the stapling actuator (3) and the articulation joint actuator (4) traverse. The medical device further comprises a surgical stapling end effector (1, 20, 30) and a passive articulating joint (10) connecting the stapling end effector (1, 20, 30) to the control handle (2) and articulating about an articulation axis. The articulation joint actuator (4) holds the passive articulating joint (10) and the surgical stapling end effector (1, 20, 30) in a substantially fixed articulation position when it is in its unactuated state, while the articulation joint actuator (4) releases the passive articulating joint (10) into a freely articulating state when it is in its actuated state.