Circular Stapler Anvil Alignment via Asymmetric Intermediary
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Solution Overview
Problem
Conventional circular stapling devices often experience misalignment between the anvil head and staple cartridge, leading to malformed staples and ineffective tissue sealing due to spline collisions during the alignment process.
Innovation Solution
The introduction of an alignment member within the anvil assembly's channel, which engages an asymmetric trocar tip to rotate the anvil assembly, ensuring proper alignment with the staple cartridge by using a combination of protrusions and concavities to secure the anvil assembly to the trocar, preventing spline collisions and ensuring correct staple formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If splines on the center rod and housing are used to align the anvil head with the staple cartridge, then alignment between the anvil and staple cartridge is achieved, but spline collisions occur causing misalignment and malformed staples
Solution Approach 1:
An alignment member with asymmetric features is introduced as an intermediary between the center rod and trocar tip. This alignment member mediates the alignment process by engaging the asymmetric trocar tip to rotate the anvil assembly into proper alignment, preventing direct spline collision while ensuring accurate positioning of the anvil head relative to the staple cartridge
Solution Approach 2:
The alignment member incorporates asymmetric features including an asymmetric trocar tip engagement surface and protrusions/concavities that correspond to asymmetric features on the trocar. This asymmetry ensures unidirectional rotation and precise alignment orientation, eliminating the misalignment problems caused by symmetric spline collisions
2Ease of operation
If the anvil assembly is rotated into alignment using spline engagement, then the anvil head aligns with the staple cartridge, but spline collision causes improper alignment and staple malformation
Solution Approach 1:
The alignment member serves as an intermediary mechanism that facilitates the rotation operation while preventing harmful spline collisions. It provides a controlled engagement interface between the center rod and trocar tip, enabling smooth rotational alignment without the impact forces that cause misalignment
Solution Approach 2:
The invention converts the potential harm of spline collision into a beneficial controlled engagement mechanism. The alignment member's asymmetric features are designed to engage the trocar tip in a way that transforms the collision force into controlled rotational motion, ensuring proper alignment while eliminating the harmful impacts
Data Source
Figure 1
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AI summary
A circular stapling device includes an anvil assembly and an adaptor assembly including a shell assembly. The adaptor assembly includes an anvil retainer including an asymmetric tip. The anvil assembly has a center rod, an anvil head supported on the center rod, and an alignment member. The center rod has a proximal portion and a distal portion and defines a channel that extends from the proximal portion to the distal portion. The alignment member is positioned within the channel and is configured to engage the asymmetric trocar tip of the anvil retainer of the adaptor when the anvil assembly is attached to the anvil retainer to properly align the anvil assembly with the shell assembly.