Vitrectomy Cutter Stop for Precision Port Positioning

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Solution Overview

Problem

Vitrectomy instruments face precision issues due to dimensional changes caused by thermal cycling and adhesive connections, leading to inefficiencies in removing vitreous fibers, especially those close to the retina, due to increased distances between components and imprecise cutting edge positioning.

Innovation Solution

The design incorporates a reciprocating cutter with a diaphragm-driven inner tube and metal components welded together, reducing dimensional variations by minimizing the use of plastic parts and adhesive connections, ensuring precise control of the cutting edge's position relative to the port.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If plastic parts and adhesive connections are used in the vitrectomy instrument, then ease of manufacture is improved, but manufacturing precision deteriorates due to dimensional changes from thermal cycling

Engineering Contradiction:
Improveease of manufactureVSAvoiddimensional stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the material parameter from plastic to metal for the needle and cutter components. This material substitution fundamentally alters the dimensional stability parameter, eliminating thermal cycling effects and adhesive-related dimensional changes while maintaining manufacturing capability through established metal fabrication processes

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes the adhesive connections from the instrument structure entirely. By eliminating the adhesive layer between the needle and cutter components, the design eliminates the dimensional instability caused by adhesive curing and thermal expansion differences, achieving precise dimensional control without requiring adhesive bonding

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If the cutting edge is positioned farther from the distal end of the needle, then ease of manufacture is improved, but productivity deteriorates due to increased distance affecting fiber removal efficiency

Engineering Contradiction:
Improveease of manufactureVSAvoidvitreous fiber removal efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent utilizes pneumatic pressure differentials to control the precise positioning of the cutter assembly relative to the needle. By applying controlled air pressure, the system achieves accurate positioning of the cutting edge at minimal distance from the needle tip, enabling efficient vitreous fiber removal while maintaining manufacturing feasibility through pneumatic actuation mechanisms

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 approach enhances the precision and efficacy of vitreous fiber removal by maintaining consistent dimensions and reducing positional variations, allowing the cutting edge to be positioned closer to the distal end of the needle, facilitating the removal of fibers near the retina.

Implementation Method 1

The diaphragm may be connected to the inner tube of the reciprocating cutter such that the inner tube is movable with the diaphragm

Methodology Applied
Scientific EffectPneumatic pressure: Pressure Increase

Implementation Method 2

metal components welded together, reducing dimensional variations by minimizing the use of plastic parts and adhesive connections

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 3

dimensional changes caused by thermal cycling

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3790518B1Vitrectomy instrument with precision cutter stop
Publication Date: 2023.08.16 ALCON INC
  • EP3790518B1 patent drawingFigure 1
  • EP3790518B1 patent drawingFigure 2~4
  • EP3790518B1 patent drawingFigure 5~6

AI summary

Provided herein are vitrectomy instruments and related systems and methods in which the vitrectomy instruments may include a forward needle stop and a cutter stop to reduce dimensional variation of a cutter of the vitrectomy instruments, allowing for a location of the port formed in a needle of the cutter to be positioned closer to a distal tip of the cutter. With the port located closer to a distal end of the cutter, the port is able to be positioned closer to the retina of an eye.