Stapler End Effector Lockout for Unspent Cartridge Verification

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Solution Overview

Problem

Existing surgical instruments face issues where clinicians may inadvertently actuate the tissue cutting member without properly installing an unspent staple cartridge, leading to improper stapling or excessive tissue incision.

Innovation Solution

The surgical instruments are equipped with lockout mechanisms that prevent the actuation of the tissue cutting member unless an unspent staple cartridge is properly installed, using mechanisms such as threaded nuts, deflectable shafts, and engagement notches to ensure the sled is in the starting position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lockout mechanism is implemented to prevent cutting member actuation without proper cartridge installation, then surgical safety and precision are improved, but device complexity increases

Engineering Contradiction:
Improvesurgical safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lockout mechanism performs preliminary verification of staple cartridge installation before allowing cutting member actuation. The interlocking features (protrusions and recesses) must be properly engaged before the firing trigger can be actuated, ensuring the cartridge is correctly installed in advance of the cutting action.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sled acts as an intermediary component between the staple cartridge and the cutting member actuation system. The sled's position and engagement with the channel's locking features serve as a mediator that verifies proper cartridge installation before permitting the cutting member to advance, thus improving safety without directly modifying the cutting mechanism itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If lockout mechanisms with threaded nuts and deflectable shafts are used to ensure proper cartridge installation, then surgical precision is maintained, but ease of operation decreases

Engineering Contradiction:
Improvesurgical precisionVSAvoidease of operation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The lockout mechanism is designed to be self-verifying through the engagement of interlocking features. When the staple cartridge is properly installed, the sled automatically engages with the channel's protrusions and recesses, and the deflectable shaft naturally positions itself to either permit or prevent cutting member actuation based on the cartridge's presence and correctness, eliminating the need for separate verification steps.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The deflectable shaft introduces dynamic behavior to the lockout mechanism. The shaft can flex or deflect in response to the sled's position, automatically adjusting its state based on whether a proper cartridge is installed. This dynamic response simplifies operation by providing intuitive feedback and automatic engagement/disengagement based on cartridge installation status.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4292545B1Cartridge lockout arrangements for rotary powered surgical cutting and stapling instruments
Publication Date: 2025.11.19 ETHICON INC
  • EP4292545B1 patent drawingFigure 1
  • EP4292545B1 patent drawingFigure 2~3
  • EP4292545B1 patent drawingFigure 4~6

AI summary

A surgical cutting and stapling end effector. Various embodiments comprise a channel that is configured to operably support a removable staple cartridge. A rotary end effector drive shaft is supported within the channel and is configured to move a firing assembly longitudinally within the end effector to cause the sled to eject surgical staples from the staple cartridge. The firing assembly is prevented from moving distally through the channel unless a surgical staple cartridge that has a sled in a starting position has been seated within the channel.