Circular Stapler Independent Actuation Mechanism
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Solution Overview
Problem
Existing circular stapling instruments require simultaneous actuation for staple formation and tissue cutting, limiting staple formation height to the knife travel distance and necessitating sufficient force for both functions, which can lead to inefficiencies and suboptimal results.
Innovation Solution
A circular stapler with a cartridge assembly that allows independent actuation of staple forming and tissue cutting, utilizing a pusher assembly and knife assembly with a snap ring mechanism that enables separate strokes for staple formation and cutting, allowing for varying staple crimp height and travel speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simultaneous actuation of staple forming mechanism and knife advancement is used, then the device structure is simplified, but the force requirement increases and staple formation height is limited to knife travel distance
Solution Approach 1:
The patent divides the simultaneous actuation into two separate, independently controllable strokes: a first stroke for staple formation and a second stroke for tissue cutting. This segmentation allows each function to be optimized independently, reducing the force requirement for each individual stroke while maintaining overall device functionality.
2Device complexity
If simultaneous actuation of staple forming mechanism and knife advancement is used, then the device structure is simplified, but staple formation height is limited to knife travel distance
Solution Approach 1:
By separating staple formation and cutting into independent strokes, the patent allows the staple forming mechanism to travel a greater distance during the first stroke without being constrained by the knife's travel distance. This enables increased staple formation height while maintaining a simplified device structure.
3Force
If independent strokes for staple formation and cutting are used, then force requirements are reduced and staple formation height can be optimized, but the device complexity increases
Solution Approach 1:
The patent employs a dynamic coupling mechanism between the pusher assembly and knife assembly that allows selective engagement and disengagement. During the first stroke, the pusher and knife are decoupled to allow independent movement; during the second stroke, they are coupled to advance together. This dynamic configuration enables independent stroke control while managing device complexity.
Solution Approach 2:
The patent introduces a coupling mechanism as an intermediary element between the pusher assembly and knife assembly. This intermediary allows controlled connection and disconnection, enabling independent actuation of staple formation and cutting functions while maintaining a manageable device structure.
4Manufacturing precision
If independent strokes are used, then staple crimp height and travel speed can be optimized, but the operation time increases
Solution Approach 1:
The patent implements a two-stroke periodic action where the first stroke performs staple formation with optimized crimp height and the second stroke performs cutting. This periodic separation allows each function to be optimized for its specific parameters while maintaining efficient overall operation through rapid sequential execution.
Data Source
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AI summary
A circular stapling instrument (10) including a stapling forming assembly that is actuated independently from actuation of the cutting assembly is provided. The instrument includes a handle assembly (20), an elongate body (30) extending from the handle assembly (20, a cartridge assembly (110) mounted on a distal end of the elongate body (30). The cartridge assembly (110) includes a pusher assembly (130A) and a knife assembly (160A). The knife assembly (160A) is selectively fixed relative to the pusher assembly (130A).