Surgical Stapler Lockout Feature Prevents Inadvertent Cutting

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Solution Overview

Problem

Existing surgical staplers lack an effective lockout mechanism to prevent inadvertent firing when a staple cartridge is not loaded or after staples have been driven, which can lead to tissue being severed without being stapled.

Innovation Solution

Incorporating a lockout feature within the end effector that prevents the firing beam and cutting edge from advancing without a properly loaded staple cartridge, using a blade assembly with a resilient member and engagement features to visually indicate the lockout status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lockout mechanism is added to prevent inadvertent firing, then safety and reliability are improved, but device complexity increases

Engineering Contradiction:

Improveprevention of inadvertent firingVSAvoidstructure of end effector

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lockout feature is integrated into the blade assembly structure itself, combining the cutting function with the lockout function in a single unified component rather than adding a separate mechanism. The engagement features are built into the blade assembly walls, merging multiple functions into one assembly.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The resilient member automatically engages with the engagement features when the blade assembly is properly positioned, creating a self-locking mechanism that does not require external actuation or complex control systems. The system self-regulates based on the presence or absence of the staple cartridge.

Inventive Principle:

Principle #25Self-service

2Ease of operation

If engagement features are added to visually indicate lockout status, then ease of operation is improved, but device complexity increases

Engineering Contradiction:

Improvevisual indication of lockout statusVSAvoidblade assembly structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The engagement features are designed to be visually distinct, allowing the operator to easily see whether the lockout is engaged or disengaged. The resilient member's position can be observed to determine the lockout status, providing visual feedback without requiring additional indicators.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The engagement features serve multiple functions: they provide the mechanical lockout interface, they offer visual indication of status, and they guide proper assembly of the staple cartridge. This multi-functionality reduces the need for separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If a resilient member is used for the lockout mechanism, then reliability is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveconsistency of lockout engagementVSAvoidengagement feature alignment

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The resilient member allows for tolerance compensation by deforming elastically to accommodate variations in manufacturing precision. The engagement features are designed with dimensions that work with the resilient member's elastic properties to ensure reliable engagement even with normal manufacturing variations.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The resilient member acts as a cushion that absorbs dimensional variations and misalignments before they can cause engagement failures. This pre-compliance feature ensures reliable lockout engagement without requiring extremely tight manufacturing tolerances.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

Ensures that tissue is not inadvertently severed without being stapled, providing a secure mechanism to prevent misfiring and ensuring proper cartridge loading before tissue manipulation.

Implementation Method 1

a blade assembly with a resilient member... the resilient member is configured to bias the blade assembly in a first position and allow the blade assembly to move longitudinally from the first position to a second position

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP3117778B1Lockout feature for movable cutting member of surgical instrument

Publication Date: 2019.05.08 ETHICON INC

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AI summary

An end effector for use with a surgical instrument includes a first jaw, a second jaw, a blade assembly, and a lockout assembly. The first jaw removably couples with a staple cartridge. The second jaw is movably coupled with the first jaw. The blade assembly translates relative to the first jaw and includes a first tab. The lockout assembly includes a resilient member that biases the blade assembly to a lockout position. The lockout assembly engages the first tab of the blade assembly in the lockout position to prevent the blade assembly from translating distally relative to the first jaw when a staple cartridge is absent from the first jaw or when a spent staple cartridge is disposed in the first jaw.