Surgical Stapler Firing Lockout for Cartridge Presence Detection
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Solution Overview
Problem
Existing surgical staplers lack a mechanism to prevent firing when the end effector is loaded with a spent staple cartridge or without any cartridge, potentially leading to unintended tissue severing without stapling.
Innovation Solution
Incorporation of a lockout assembly that includes a sensor and lockout mechanism to inhibit firing when a spent or absent staple cartridge is detected, ensuring the end effector is properly loaded before firing is enabled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surgical stapler is designed without a firing lockout mechanism, then the device complexity is reduced and ease of operation is improved, but the reliability deteriorates due to potential unintended firing with spent or absent cartridges
Solution Approach 1:
The lockout assembly prevents firing before the cartridge is properly loaded by requiring a preliminary loading action that releases the lockout. The biased lockout component remains in a locked position preventing knife movement until the cartridge is correctly inserted and engages the release feature, ensuring safety before operation.
Solution Approach 2:
The lockout assembly acts as an intermediary mechanism between the cartridge loading state and the firing capability. It mediates by physically blocking knife movement when the cartridge is absent or spent, and only allowing firing when the cartridge is properly loaded and the lockout is released through the engagement of loading features.
2Reliability
If a lockout assembly is added to prevent unintended firing, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The lockout assembly is merged with the existing end effector structure, integrating the safety function into the cartridge loading mechanism itself. The lockout component utilizes the same spatial and structural relationships as the cartridge loading features, combining multiple functions (loading guidance, presence detection, firing enablement) into a unified assembly rather than adding separate independent systems.
Solution Approach 2:
The lockout assembly serves multiple functions: it detects cartridge presence, verifies proper loading, prevents unintended firing, and enables firing when conditions are met. This multi-functional design consolidates several safety and operational roles into a single integrated mechanism, reducing the need for separate components for each function.
3Reliability
If the lockout mechanism requires precise engagement features for cartridge detection, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The cartridge and lockout assembly are segmented into distinct functional features with clear separation of responsibilities. The cartridge has dedicated loading engagement features that are structurally distinct from other components, allowing for modular manufacturing and assembly. This segmentation enables each feature to be manufactured and verified independently with appropriate tolerances.
Solution Approach 2:
The engagement features between cartridge and lockout assembly are designed with localized geometric properties optimized for their specific function. The features have specific shapes, sizes, and surface characteristics tailored to ensure reliable engagement and detection, while other parts of the components can have different quality requirements. This local optimization allows high precision only where absolutely necessary.
Data Source
AI summary
An apparatus includes a body, a shaft, an end effector, and a lockout assembly. The end effector includes a cartridge jaw, an anvil jaw, a knife and a distal retainer. The lockout assembly includes a sensor and a lockout. The lockout is vertically constrained. The sensor is associated with a first pivot and a second pivot. The first pivot is grounded with respect to a channel. The second pivot is a moving pivot. The lockout assembly includes an unlocked and locked position. The second pivot is positioned above the first pivot when the lockout assembly is in the unlocked position with the lockout providing no interference with respect to actuation of the knife. The first pivot and the second pivot are positioned at substantially the same height when the lockout assembly is in the locked position.