Surgical End Effector Lockout for Missing Staple Cartridges

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Solution Overview

Problem

Existing surgical instruments lack a mechanism to prevent accidental advancement of the firing member when a staple cartridge is missing from the end effector, which can result in tissue being cut without being sealed by staples.

Innovation Solution

A lockout mechanism is introduced that includes a lockout lever movable between unlocked and locked orientations, preventing the advancement of the firing member if a cartridge is not present, and a spring intermediate the proximal and distal portions of the firing assembly to sense the position of the firing assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lockout mechanism is added to prevent accidental advancement of the firing member, then safety is improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lockout lever is merged with the existing firing assembly components. The lever integrates with the notched portion of the firing member and the spring mechanism, combining the lockout function with the existing firing control structure rather than adding a completely separate system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spring-loaded lockout lever automatically engages with the notched portion when the firing member is in the retracted position, and automatically disengages when the firing member advances. The mechanism self-regulates based on the firing member's position without requiring external control.

Inventive Principle:
Principle #25Self-service

2Reliability

If a spring mechanism is added to sense the position of the firing assembly, then reliability is improved, but device complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring mechanism serves multiple functions: it biases the lockout lever toward engagement, senses the position of the firing assembly through its deformation, and provides the force necessary for the lockout mechanism to operate. This multi-functional design reduces the need for separate sensing and actuation systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The spring acts as an intermediary element between the firing member and the lockout lever. It translates the position of the firing member into mechanical force that either engages or disengages the lockout lever, providing a simple mechanical sensing and actuation interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Prevents accidental advancement of the firing member when a cartridge is missing, ensuring that tissue is both cut and sealed by staples, enhancing safety and functionality of the surgical instrument.

Implementation Method 1

a spring intermediate said proximal portion and said distal portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4183350B1Lockout arrangements for surgical end effectors and replaceable tool assemblies
Publication Date: 2026.02.25 ETHICON INC
  • EP4183350B1 patent drawingFigure 1
  • EP4183350B1 patent drawingFigure 1A
  • EP4183350B1 patent drawingFigure 2

AI summary

Surgical end effectors are disclosed. The surgical end effectors can include a first jaw, a second jaw rotatably coupled to the first jaw, and a lockout arrangement configured to prevent rotational movement of the second jaw toward the first jaw unless an unfired staple cartridge is positioned in the first jaw. The lockout arrangement can comprise a pivotable lock configured to pivot between a locked orientation and an unlocked orientation, a shiftable lock bar, and/or a spring-loaded lockout lever.