Surgical Anvil Lockout Mechanism Prevents Partial Assembly

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Solution Overview

Problem

Current surgical stapling instruments face challenges in ensuring proper assembly and operation, particularly in preventing partial assembly of the anvil to the trocar shaft, which can lead to detachment during tissue compression, and in ensuring sufficient clamping pressure before staple firing.

Innovation Solution

Incorporating lockout mechanisms, such as compliant arms and retraction locks, to prevent partial assembly of the anvil and requiring sufficient clamping pressure before allowing staple firing, ensuring secure attachment and proper operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the anvil is made detachable from the trocar shaft for sterilization and assembly flexibility, then ease of manufacture and sterilization are improved, but the risk of partial assembly and detachment during operation increases

Engineering Contradiction:
Improveassembly flexibilityVSAvoidattachment security
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The anvil assembly includes a lockout mechanism that performs preliminary action by preventing the anvil from being detached unless properly assembled. The compliant arm with lockout feature engages with the trocar shaft before operation, ensuring that any partial assembly attempts are blocked in advance, thus preventing detachment during use while maintaining assembly flexibility.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The compliant arm acts as an intermediary between the anvil and the trocar shaft. It provides a mechanical linkage that includes a lockout feature, serving as a mediator that ensures proper assembly while allowing detachment for sterilization. The intermediary mechanism translates assembly status into lockout engagement, resolving the contradiction between detachability and security.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If lockout mechanisms are added to prevent partial assembly, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveassembly correctnessVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lockout mechanism utilizes a compliant arm, which is a flexible mechanical element. This flexible component provides the lockout function through elastic deformation and engagement features, achieving reliable assembly verification without requiring complex rigid mechanical linkages or multiple separate components, thus minimizing added complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The lockout feature is merged directly into the compliant arm structure rather than being a separate mechanism. The compliant arm combines multiple functions: structural support, motion guidance, and lockout enforcement. This merging reduces the total number of components and simplifies the overall device while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If clamping pressure monitoring is implemented before staple firing, then surgical safety is improved, but device complexity and operation time increase

Engineering Contradiction:
Improvetissue damage riskVSAvoidprocedure time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system implements self-service clamping pressure monitoring where the mechanical closure action itself generates and monitors the clamping pressure. The anvil closure drive mechanism inherently provides the clamping force, and the lockout mechanism automatically verifies sufficient pressure is achieved before allowing staple firing. This self-verification eliminates the need for separate monitoring devices or manual checks, avoiding additional time loss.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3225192B1Circular stapling system comprising an incisable tissue support
Publication Date: 2022.04.06 ETHICON INC
  • EP3225192B1 patent drawingFigure 1
  • EP3225192B1 patent drawingFigure 2
  • EP3225192B1 patent drawingFigure 3

AI summary

A surgical instrument comprising an end effector is disclosed. The end effector comprises a staple cartridge including a cartridge body comprising an annular array of staple cavities, staples removably stored in the staple cavities, a firing drive configured to eject the staples from the staple cavities, and a cutting member circumscribed by the staple cavities. The end effector further comprises an anvil including a tissue compression surface, forming surfaces configured to deform the staples and a tissue block. The anvil is movable toward the cartridge body to compress tissue between the cartridge body and the tissue block and the cutting member is configured to incise the tissue and the tissue block during a cutting stroke of the cutting member.