Small Gauge Tissue Cutter Probe for Glaucoma Surgery

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Solution Overview

Problem

Current surgical procedures for glaucoma, such as removing or bypassing the trabecular meshwork, have drawbacks, and there is a need for a more effective method to restore aqueous humor flow by removing trabecular meshwork tissue without causing damage to the eye structures.

Innovation Solution

A small gauge mechanical tissue cutter/aspirator probe with a retractable pick is designed to be guided into Schlemm's canal, where the cutting port is positioned at the trabecular meshwork to cut and remove the obstructive tissue, utilizing a cylindrical outer cannula and a reciprocating inner cannula for effective tissue aspiration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing surgical procedures are used to remove or bypass the trabecular meshwork, then aqueous humor flow can be restored, but damage to eye structures may occur

Engineering Contradiction:
Improvesurgical effectivenessVSAvoiddamage to eye structures
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The outer cannula functions as a flexible protective shell that shields the inner cannula and retractable pick during insertion and positioning. This flexible protective structure allows the device to navigate the delicate eye anatomy while preventing direct contact between rigid cutting components and surrounding tissues, thereby restoring aqueous humor flow without causing damage to eye structures.

Inventive Principle:
Principle #30Flexible shells and thin films

2Productivity

If a mechanical tissue cutter is used to remove trabecular meshwork, then tissue removal is effective, but precision in positioning the cutting port is required

Engineering Contradiction:
Improvetissue removal efficiencyVSAvoidcutting port positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The retractable pick is extended before insertion to pierce the trabecular meshwork and create a pilot opening. This preliminary action establishes the correct positioning and orientation of the device before the inner cannula is advanced to the cutting position, ensuring that the cutting port is accurately positioned at the trabecular meshwork for effective tissue removal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The retractable pick can be extended and retracted dynamically during the procedure. It is extended for initial penetration and tissue engagement, then retracted to allow the inner cannula to advance to the precise cutting position. This dynamic adjustment enables both effective tissue removal and accurate positioning of the cutting port.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the inner cannula reciprocates within the outer cannula, then tissue aspiration is effective, but device complexity increases

Engineering Contradiction:
Improvetissue aspiration efficiencyVSAvoidcannula reciprocation mechanism
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The inner cannula is connected to a diaphragm that reciprocates the cannula automatically through pressure differential. During aspiration, negative pressure causes the diaphragm to flex outward, pushing the inner cannula forward; during discharge, the diaphragm returns to its original position, pulling the inner cannula backward. This self-service mechanism eliminates the need for complex external actuators while maintaining effective tissue aspiration.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution allows for precise removal of trabecular meshwork tissue, effectively restoring aqueous humor flow and reducing intraocular pressure, while minimizing damage to the eye structures, thus addressing the limitations of existing surgical methods.

Implementation Method 1

a second smaller gauge cannula located within first outer cannula connected to a diaphragm that reciprocates the second inner cannula within and along the axis of the first outer cannula

Methodology Applied
Scientific EffectReciprocating motion:

Implementation Method 2

small gauge mechanical tissue cutter/aspirator probe

Methodology Applied
Scientific EffectAspiration: Suction

Data Source

PatentEP2303203B1Small gauge mechanical tissue cutter/aspirator probe for glaucoma surgery
Publication Date: 2012.06.20 ALCON RESEARCH LTD
  • EP2303203B1 patent drawingFigure 1~2B
  • EP2303203B1 patent drawingFigure 3~5A
  • EP2303203B1 patent drawingFigure 5B~6B

AI summary

A small gauge mechanical tissue cutter/aspirator probe useful for removing the trabecular meshwork of a human eye has a generally cylindrical outer cannula, an inner cannula that reciprocates in the outer cannula, a port located near or at the distal end of the outer cannula on a side or tip of the outer cannula, and a guide with a distal surface located on the distal end of the outer cannula. A distance between the distal surface of the guide and the port is approximately equal to the distance between the back wall of Schlemm's canal and the trabecular meshwork.