Linear Stapler Unit Lockout Prevents Misaligned Firing
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Solution Overview
Problem
Surgical stapling and cutting instruments often inadvertently fire when not properly aligned with the tissue, leading to inefficiencies and potential errors, especially in reusable end effectors where proper alignment is crucial for repeated operations.
Innovation Solution
A unit lockout mechanism is integrated into the linear stapler, featuring a rotatable lockout component with a pivot and blocking plates that prevent the trigger from firing unless the stapler is correctly aligned with the tissue, ensuring proper alignment before allowing the stapler to function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reusable end effector is used for multiple operations, then economic efficiency is improved, but the risk of inadvertent firing increases when not properly aligned
Solution Approach 1:
The lockout mechanism performs a preliminary check of alignment conditions before allowing the trigger to fire. The unit lockout component is positioned and oriented in advance based on the position of the anvil and cartridge, ensuring that firing is only permitted when proper alignment is already established, thus preventing inadvertent firing while maintaining reusable end effector efficiency
2Reliability
If lockout features are added to prevent inadvertent firing, then safety is improved, but device complexity increases
Solution Approach 1:
The unit lockout combines multiple safety functions into a single integrated component. This lockout component simultaneously prevents trigger activation, blocks the anvil from moving into the cartridge, and provides alignment indication, thereby achieving enhanced safety with minimal additional complexity by merging what could have been separate mechanisms into one unified element
3Ease of operation
If the trigger can be freely actuated, then ease of operation is improved, but inadvertent firing occurs when misaligned
Solution Approach 1:
The unit lockout acts as an intermediary between the trigger and the firing mechanism. It sits in the trigger path and mechanically blocks the trigger from activating the firing sequence unless specific alignment conditions are met. This intermediary component allows the trigger to remain accessible for operation while preventing harmful firing when the anvil and cartridge are misaligned, thus protecting tissue from trauma
Data Source
AI summary
The present invention relates to a surgical stapler comprising: a support base; a trigger; a handle; a retaining pin operatively connected to and extending distally from a support base, the support base being operable in the surgical stapler to cause the stapler to position staples near tissue; and a unit lockout rotatable about a pivot fixed to the handle. The unit lockout comprises an upper end near and under at least one blocking plate in the stapler; and another end facing the trigger to prevent it from firing when the upper end is blocked from upward movement by the at least one blocking plate. Whereas the upper end of the unit lockout is moved relative to the at least one blocking plate so that the upper end of unit lockout is no longer under the at least one blocking plate to permit the unit lockout to rotate about the pivot.