Circular Stapler Trigger Lock for Fixed Tissue Gap Control
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Solution Overview
Problem
Existing surgical stapling apparatuses face challenges in securely locking the tissue gap between the anvil and cartridge assemblies, which can lead to improper staple formation and ergonomic issues due to limited internal space.
Innovation Solution
A trigger lock mechanism is integrated into the handle assembly, allowing the tissue gap to be set and locked at a predetermined size before firing, using a latch assembly and catch system to prevent unintended unclamping, while reducing the span of the trigger for improved ergonomics and usability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the trigger span is reduced to improve ergonomics, then ease of operation is improved, but the ability to securely lock the tissue gap may be compromised
Solution Approach 1:
The locking mechanism is segmented into distinct components: a trigger lock with latch assembly that engages with the trigger, and a screw stop with engagement tooth that engages with the pivot member. This segmentation allows each component to perform its specific function independently, ensuring reliable tissue gap locking while maintaining a compact trigger design for improved ergonomics.
Solution Approach 2:
The latch assembly is positioned within the trigger structure, and the engagement tooth is integrated into the screw stop component. These nested arrangements allow the locking mechanisms to be contained within the existing handle assembly footprint without increasing the trigger span, thus maintaining ergonomics while ensuring reliable locking.
2Device complexity
If the internal space of the handle assembly is limited, then device complexity is reduced, but the ability to securely lock the tissue gap becomes difficult
Solution Approach 1:
The trigger lock and latch assembly are merged with the existing trigger structure, and the screw stop is integrated into the drive screw assembly. This merging of functions into existing components allows the locking mechanisms to be implemented without adding significant structural complexity to the handle assembly, while still providing reliable tissue gap locking capability.
Solution Approach 2:
The trigger lock serves dual functions: it locks the trigger to prevent inadvertent firing and simultaneously enables the screw stop to lock the anvil and cartridge assemblies in the clamped position. This multi-functionality reduces the need for separate dedicated locking components, thereby limiting device complexity while ensuring reliable tissue gap locking.
3Ease of operation
If the trigger lock is disengaged to allow unclamping, then ease of operation is improved, but inadvertent firing may occur
Solution Approach 1:
The trigger lock is designed to remain engaged during the unclamping process, and the screw stop prevents the anvil and cartridge assemblies from unclamping until the trigger lock is intentionally disengaged. This preliminary locking action prevents inadvertent firing while still allowing controlled unclamping when the surgeon intentionally disengages the trigger lock.
Solution Approach 2:
The trigger lock acts as an intermediary between the trigger and the firing mechanism. It must be intentionally disengaged to allow the trigger to move and fire, providing a deliberate intermediate step that prevents accidental firing while maintaining ease of operation when the surgeon intentionally wants to unclamp or fire the device.
Data Source
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AI summary
A circular stapling apparatus is disclosed, which includes a stationary handle (18), a trigger (20) pivotally coupled to the stationary handle (18), a trigger lock (24) selectively engageable with the trigger (20), and a firing link (44) coupled to the trigger (20). The firing link (44) has a catch (45) thereon. The trigger lock (24) has a latch assembly (25) that is selectively engageable with the catch (45).