Flexible Shaft Surgical Instrument Locking Mechanism

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Solution Overview

Problem

Surgical instruments require multiple angled configurations and orientations, leading to the need for a large variety of instruments, which is costly and inefficient.

Innovation Solution

A flexible-shaft surgical instrument with a semi-rigid tube composed of links that can be bent and locked into various angles using a compression mechanism, allowing for user-selectable orientations without significant plastic deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple surgical cutting blades with different fixed angles are provided, then the surgeon can precisely orient the cutting blade at specific angles, but the cost increases and inventory management becomes complex

Engineering Contradiction:
Improveorientation precisionVSAvoidnumber of blades
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The surgical cutting blade is designed with a flexible shaft portion that can be dynamically bent to different angles and locked into position. This allows a single blade to provide multiple orientation configurations rather than requiring multiple fixed-angle blades, resolving the contradiction between orientation precision and quantity of blades needed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The blade's orientation parameter is made variable through the flexible shaft mechanism. The shaft can be bent to change the angle parameter, and the locking mechanism maintains the changed parameter. This transforms a fixed-parameter system (multiple blades with different angles) into a variable-parameter system (single blade with adjustable angle)

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a flexible shaft portion is provided to allow bending, then the instrument can be oriented at various angles, but the shaft may undergo significant plastic deformation affecting future bending capability

Engineering Contradiction:
Improvebending flexibilityVSAvoidrepeatability of bending
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The shaft is segmented into multiple rigid segments connected by articulation points. This segmentation allows the shaft to bend in a controlled manner through discrete segment movements rather than continuous deformation, enabling the shaft to return to its original configuration after bending and locking, thus maintaining reliability for repeated use

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking mechanism is engaged before significant plastic deformation can occur. The mechanism includes features such as detents or clamps that secure the shaft segments in position during bending, preventing excessive deformation that would compromise future bending capability. This preliminary locking action preserves the shaft's reliability

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3695795B1Locking flexible surgical instruments
Publication Date: 2023.10.04 GYRUS ACMI INC
  • EP3695795B1 patent drawingFigure 1
  • EP3695795B1 patent drawingFigure 2A~2B
  • EP3695795B1 patent drawingFigure 3A~3B

AI summary

A flexible-shaft surgical instrument has a compression member that is distally movable to provide a compression force between the compression member and a distal compression bearing to compress a plurality of links and rigidly lock a semi-rigid tube formed by those links at any of a variety of user-selectable predetermined positions. The semi-rigid tube is configured to be bent and locked at the user-selectable predetermined position and, upon proximal movement of the compression member, returned to an unlocked state without significant plastic deformation of the semi-rigid tube.