Torque Limiting Knob for Circular Stapling Instruments

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Solution Overview

Problem

Current surgical stapling instruments lack effective mechanisms for ensuring precise tissue clamping and stapling while preventing excessive force that could damage tissue during end-to-end anastomosis procedures.

Innovation Solution

The development of a circular stapling surgical instrument featuring a torque limiting adjustment knob and override feature, which allows for controlled clamping force and prevents excessive force application, ensuring secure tissue stapling and minimizing tissue damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If clamping force is increased to ensure secure tissue stapling, then stapling reliability is improved, but tissue damage risk increases

Engineering Contradiction:
Improvestapling reliabilityVSAvoidtissue damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by implementing a torque limiting mechanism that controls the clamping force parameter. The torque limiting adjustment knob restricts the rotational torque to a predetermined maximum, thereby limiting the clamping force to a safe range that ensures reliable stapling while preventing tissue damage. This directly addresses the contradiction by modifying the force parameter to operate within optimal boundaries.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates feedback through the torque limiting mechanism that provides real-time control over clamping force application. When the predetermined maximum torque is reached, the mechanism prevents further force increase, creating a feedback loop that maintains clamping force within safe limits. This feedback system ensures that stapling reliability is maintained without exceeding tissue damage thresholds.

Inventive Principle:
Principle #23Feedback

2Object-affected harmful factors

If clamping force is limited to prevent tissue damage, then tissue safety is improved, but stapling security may be compromised

Engineering Contradiction:
Improvetissue damage preventionVSAvoidstapling security
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The torque limiting mechanism optimizes the clamping force parameter by setting it to a predetermined maximum that is sufficient for secure stapling while preventing tissue damage. This parameter optimization resolves the contradiction by identifying and maintaining the optimal force level that simultaneously achieves stapling security and tissue safety.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies partial action by providing an override feature that allows temporary exceeding of the predetermined torque limit when thicker tissues require additional force. This partial override capability ensures that stapling security is maintained even in challenging cases, while the default limited force prevents tissue damage in normal circumstances.

Inventive Principle:
Principle #16Partial or excessive action

3Object-affected harmful factors

If torque limiting mechanism is added to control clamping force, then tissue damage prevention is improved, but device complexity increases

Engineering Contradiction:
Improvetissue damage preventionVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The torque limiting adjustment knob integrates multiple functions into a single component: it limits torque to prevent tissue damage, allows adjustment of the torque limit, and provides an override capability when needed. This multi-functionality reduces overall device complexity compared to having separate mechanisms for each function.

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

Solution Approach 2:

The patent merges the torque limiting mechanism with the existing adjustment knob structure, combining the force limitation function with the adjustment interface. This integration approach minimizes additional components and structural complexity while achieving tissue damage prevention.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If override feature is added for thicker tissues, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improveadaptability to different tissue typesVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The override feature implements partial action by allowing temporary exceeding of the predetermined torque limit only when needed for thicker tissues. This selective override capability enhances adaptability to different tissue types while maintaining the default torque limit for normal cases, thereby minimizing the impact on device complexity.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The override mechanism is designed to be self-contained within the existing adjustment knob structure, allowing the user to manually override the torque limit when needed without requiring additional external mechanisms. This self-service approach maintains adaptability while avoiding significant complexity increases.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3461430B1Circular stapling instrument with torque limiting feature
Publication Date: 2021.09.15 ETHICON INC
  • EP3461430B1 patent drawingFigure 1
  • EP3461430B1 patent drawingFigure 2~3
  • EP3461430B1 patent drawingFigure 4~5

AI summary

An apparatus includes a body, an anvil, a firing assembly, and a closure assembly. The firing assembly includes a staple driver, a deck member, and an annular array of staples. The closure assembly includes a trocar, a knob, and a limiting adjustment feature. The trocar is configured to actuate the anvil relative to the body to capture tissue between the anvil and the deck member. The knob is configured to rotate relative to the body to actuate the trocar relative to the body. The limiting adjustment feature is configured to selectively rotate the knob to actuate the trocar and the anvil proximally until tissue captured between the anvil and the deck member is compressed under a predetermined maximum clamping force. The limiting adjustment feature is configured to slip relative to the knob when tissue captured between then anvil and the deck member is compressed over the predetermined maximum clamping force.