Surgical Stapler Rotary Drive Lockout Mechanism

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Solution Overview

Problem

Surgical staplers lack a mechanism to prevent accidental firing after the staple cartridge is spent, which can lead to device damage and patient harm, especially in robotic systems where electrical failures may occur.

Innovation Solution

A lockout assembly that is linearly translatable and pivotable, coupled with a rotary drive member, prevents further rotation of the drive member after the sled has advanced through the end effector, ensuring the stapler remains locked in the open position post-firing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a sensor is utilized to determine end effector location or firing status, then automation and precision are improved, but reliability deteriorates due to potential electrical failures

Engineering Contradiction:

Improvesensor-based firing detectionVSAvoidelectrical failure vulnerability

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

A mechanical intermediary system (latch, drive member, and cam interactions) is introduced between the electrical sensor system and the firing mechanism. This mechanical intermediary provides a fail-safe physical intervention that prevents firing when the end effector is in an open position, regardless of sensor status or electrical system functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical lockout system is designed to prevent harmful effects before they can occur by establishing a physical barrier (latch engagement) that stops the firing sequence before it can initiate unintended firing. The system proactively prepares the mechanical intervention in advance of any potential electrical failure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If the sled can be freely advanced through the end effector, then ease of operation is improved, but harmful factors worsen due to potential damage from over-advancement

Engineering Contradiction:

Improvesled advancement freedomVSAvoiddevice damage from over-advancement

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The cam mechanism is designed to create preliminary anti-action by engaging the latch in a position that prevents further rotation of the drive member once the sled has completed its intended travel. This pre-established mechanical constraint stops the firing sequence before the sled can project through the distal end of the end effector, thereby preventing device damage.

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If a mechanical lockout system is added to prevent unintended firing, then reliability is improved, but device complexity worsens

Engineering Contradiction:

Improvefiring prevention capabilityVSAvoidlockout assembly structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The lockout assembly is merged with existing structural elements of the surgical stapler. The latch is integrated into the drive member assembly, and the cam mechanism utilizes the existing rotational motion of the drive member. This merging approach allows the lockout function to be achieved without adding entirely separate mechanical systems, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10363035B2Stapler tool with rotary drive lockout

Publication Date: 2019.07.30 CILAG GMBH INTERNATIONAL

AI summary

A surgical stapler including an end effector having various embodiments of a lockout assembly is described. The lockout assembly can control the rotation of a drive member that extends through the end effector. A sled can be positioned along the drive member and caused to translate along the drive member upon rotation of the drive member. As such, the lockout assembly can prevent movement of the sled by controlling the ability of the drive member to rotate. The lockout assembly can assist with preventing inadvertent firing of the end effector, such as when there is no cartridge present or a spent cartridge (e.g., the cartridge does not have any staples).