Surgical Stapler Knife Lockout for Stapling-Before-Cutting Control

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Solution Overview

Problem

Existing surgical stapling and cutting instruments lack effective safety mechanisms to prevent tissue cutting without prior stapling, and there is a need for improved control over knife motion to ensure proper sequencing of stapling and cutting operations.

Innovation Solution

The surgical instrument incorporates a firing lockout mechanism with a lockout pawl and sled system that prevents the firing member from advancing without an unfired staple cartridge, ensuring that stapling occurs before cutting, and includes a motor-driven control circuit to manage the firing bar and member movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a firing member is designed to advance freely to enable cutting, then cutting speed is improved, but safety is worsened due to risk of cutting without stapling

Engineering Contradiction:

Improvecutting speedVSAvoidsafety

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The lockout pawl mechanism performs a preliminary safety check before allowing the firing member to advance. It verifies that an unfired staple cartridge is present and properly positioned before permitting the cutting function to activate, ensuring that stapling occurs before cutting in the sequence of operations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The lockout pawl acts as an intermediary safety mechanism between the firing member and the tissue. It mediates the interaction by preventing the firing member from advancing unless the proper conditions (presence of unfired staple cartridge) are met, thus controlling the sequence of stapling before cutting

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a lockout pawl mechanism is added to prevent cutting without stapling, then safety is improved, but device complexity increases

Engineering Contradiction:

ImprovesafetyVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lockout pawl mechanism is merged with the existing firing member and staple cartridge assembly. The pawl integrates with the cam slot geometry and interacts with the sled, combining the safety function with the existing mechanical structure rather than adding a completely separate system

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lockout pawl mechanism is self-actuating through the cam slot geometry. As the firing member advances, the cam slot automatically moves the pawl between locked and unlocked positions without requiring external control systems, sensors, or additional actuators

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12533130B2Surgical stapler knife motion controls

Publication Date: 2026.01.27 CILAG GMBH INTERNATIONAL

AI summary

A surgical instrument includes an end effector, a firing member movable distally to effect a firing motion at the end effector, wherein the firing member comprises a cam slot, and a lockout pawl. The lockout pawl has a cam feature receivable in the cam slot, wherein the cam slot is configured to guide the cam feature to cause a rotation of the lockout pawl between a first position where the lockout pawl permits the distal movement of the firing member, and a second position where the lockout pawl prevents the distal movement of the firing member.