Surgical Stapler Cartridge Lockout for Empty-Fire Prevention
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Solution Overview
Problem
Existing surgical staplers lack effective mechanisms to prevent inadvertent firing when the staple cartridge is empty or improperly installed, leading to improper staple formation and tissue cutting without stapling.
Innovation Solution
A cartridge-based firing lockout mechanism featuring a lockout lever that is pivotably coupled to the end effector, which is biased to a locked state and cammingly engaged by the staple cartridge and wedge sled to ensure proper installation and prevent distal actuation of the pusher member when the cartridge is empty or incompatible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a firing lockout mechanism is implemented to prevent accidental firing, then patient safety and device reliability are improved, but the device complexity increases due to additional components and mechanisms
Solution Approach 1:
The firing lockout mechanism is merged with the existing trigger assembly and cartridge ejection mechanism. The trigger assembly serves dual functions: normal firing operation and lockout enforcement. The cartridge ejection mechanism is integrated with the lockout state detection, where the act of ejecting the cartridge automatically resets the lockout condition. This merging eliminates the need for separate, standalone lockout components while achieving the same safety function.
Solution Approach 2:
The system automatically detects when a cartridge is properly installed and automatically resets the lockout condition without requiring manual intervention. The cartridge ejection mechanism itself serves to reset the lockout state - when the cartridge is ejected, the trigger assembly automatically returns to its pre-lockout state, ready for the next cartridge. This self-service approach reduces complexity by eliminating manual reset buttons or switches.
2Ease of operation
If manual reset capability is provided after cartridge ejection, then ease of operation is improved, but the risk of improper operation or accidental firing increases
Solution Approach 1:
Instead of providing a manual reset mechanism that could be accidentally activated, the design inverts the approach by making the cartridge ejection action itself the reset mechanism. The system is designed so that the natural operation of ejecting the cartridge automatically resets the lockout state. This inversion ensures that reset only occurs through the intended sequence of operations, preventing accidental resets while maintaining ease of operation.
Solution Approach 2:
The trigger assembly is pre-configured with a predetermined movement path that includes both the firing position and the reset position. Before a cartridge is ejected, the system is already prepared with the mechanical configuration to automatically return to the ready state. This preliminary arrangement ensures that when ejection occurs, the reset action follows naturally from the pre-established mechanical geometry, eliminating the need for separate manual reset controls.
Data Source
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AI summary
A surgical stapling instrument includes a shaft assembly and an end effector. The end effector includes a first jaw having an anvil, a second jaw configured to removably receive a staple cartridge, and a driving assembly translatable distally through the second jaw for pivoting the second jaw toward the first jaw to clamp tissue between the first jaw and the second jaw. The instrument also includes a lockout mechanism configured to transition between a first state in which the lockout mechanism prevents distal translation of the driving assembly through the second jaw, and a second state in which the lockout mechanism permits distal translation of the driving assembly through the second jaw. The lockout mechanism is configured to transition from the first state to the second state when the staple cartridge is removably received by the second jaw.