Stapling Device Cut Ring Biasing Member
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Solution Overview
Problem
Existing circular stapling devices face issues where the annular knife sticks to the cut ring after firing, preventing the anvil head from tilting and being removed, due to the cut ring being made of softer material than the knife.
Innovation Solution
A shell assembly with a biasing member, such as a coil spring, is integrated to facilitate the separation of the annular knife and cut ring after firing, allowing the anvil head to tilt by engaging the cut ring and urging it to a distal position, ensuring proper removal of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the cut ring is made of softer material than the annular knife to facilitate penetration during firing, then the knife can effectively cut through the cut ring, but the cut ring sticks to the knife after firing preventing anvil head movement
Solution Approach 1:
A biasing member (spring) is introduced as an intermediary element between the annular knife and the cut ring. The spring applies a distal force to the cut ring, maintaining separation between the softer cut ring and the knife after firing, thereby preventing sticking while allowing the anvil head to tilt and be removed properly
Solution Approach 2:
The biasing member applies a preliminary separating force to the cut ring in the distal direction before and during the retraction of the knife. This preliminary anti-action counteracts the adhesive forces that would otherwise cause the cut ring to stick to the knife after firing, ensuring the anvil head can move to the tilted position
2Strength
If the cut ring is made softer than the annular knife for effective cutting, then the knife penetrates the cut ring during firing, but the cut ring moves back to its first position when the knife is retracted, preventing the anvil head from moving to the tilted position
Solution Approach 1:
The biasing member serves as a mediator that maintains the cut ring in the second position (advanced position) after firing. By applying continuous distal force, it prevents the cut ring from returning to the first position, ensuring reliable operation of the anvil head tilting mechanism
Solution Approach 2:
The system transitions from a static cut ring position to a dynamically controlled position using the biasing member. The spring provides continuous force to maintain the cut ring in the advanced position, creating a dynamic balance that ensures reliable post-firing operation
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 prevents the cut ring from sticking to the annular knife, enabling the anvil head to tilt and facilitating the removal of the stapling device from the patient, addressing the sticking issue and ensuring smooth post-firing operation.
Implementation Method 1
The biasing member is a coil spring
Implementation Method 2
A shell assembly with a biasing member, such as a coil spring, is integrated to facilitate the separation of the annular knife and cut ring after firing
Data Source
AI summary
A circular stapling device includes a shell assembly and an anvil assembly. The shell assembly includes a housing, a staple cartridge supported on the housing, an annular knife supported within the housing, and a biasing member supported within the housing. The anvil assembly includes a center rod and an anvil head that supports a cut ring that is axially aligned with the annular knife. The biasing member is positioned within the housing and extends to a position distally of the annular knife when the annular knife is in the retracted position to shield the annular knife. The anvil assembly is movably supported in relation to the shell assembly between an unapproximated position and an approximated position, wherein in the approximated position, the biasing member is engaged with the cut ring and urges the cut ring in a distal direction.