Pulsed Fluid Tissue Separation Minimizing Retinal Shear Stress

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Solution Overview

Problem

Current ophthalmic surgical methods for separating the vitreous humor from the retina, such as using standard vitrectomy probes or enzymes, often cause significant shear stress on the retina and may lead to unwanted side effects, making them unsatisfactory for precise procedures like posterior vitreous detachment.

Innovation Solution

A tissue separation system comprising a flexible elongate member with a fluid reservoir and pump system that delivers pulsed fluid to separate tissues, minimizing shear stress and using a control system to manage fluid pressure and pulses for precise detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard vitrectomy probes are used to mechanically detach the vitreous from the retina, then the vitreous can be separated from the retina, but significant shear stress is applied to the retina which may cause retinal tears or detachment

Engineering Contradiction:

Improvevitreous detachment effectivenessVSAvoidshear stress on retina

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical cutting and pulling action of vitrectomy probes with a chemical enzymatic system. Ocriplasmin enzyme is delivered through the flexible elongate member to chemically cleave the adhesion bonds between the vitreous and retina, eliminating the need for mechanical traction that causes shear stress and retinal damage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an enzymatic intermediary (ocriplasmin) that mediates the separation process. Instead of directly mechanically separating the vitreous from the retina, the enzyme acts as an intermediary that breaks down the adhesive proteins, allowing separation to occur through chemical dissolution of bonds rather than mechanical force.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If enzymes are used to chemically separate the vitreous from the retina, then separation can be achieved without mechanical stress, but unwanted side effects are generated

Engineering Contradiction:

Improveshear stress on retinaVSAvoidunwanted side effects from enzymes

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the parameters of enzymatic treatment by controlling the concentration, delivery rate, and exposure time of ocriplasmin. The pump system delivers the enzyme at controlled rates, and the flexible elongate member allows precise positioning, ensuring the enzyme acts only where needed and minimizing systemic side effects while maintaining effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies the enzymatic treatment locally to specific areas of vitreomacular adhesion rather than throughout the entire eye. The flexible elongate member can be positioned to deliver ocriplasmin precisely to the site of adhesion, ensuring the enzyme acts only where separation is needed and minimizing exposure to healthy tissues.

Inventive Principle:

Principle #3Local quality

3Reliability

If mechanical vitrectomy is performed to treat vitreomacular traction, then the adhered vitreous can be detached, but the procedure becomes complex and carries risk of retinal damage

Engineering Contradiction:

Improvevitreomacular adhesion resolutionVSAvoidsurgical procedure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical vitrectomy procedures with a simpler enzymatic injection approach. Instead of requiring sophisticated vitrectomy machines and complex surgical maneuvers, the treatment involves delivering ocriplasmin through a simple flexible catheter, significantly reducing procedural complexity while maintaining therapeutic effectiveness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

The system effectively separates the vitreous from the retina with reduced risk of retinal damage, addressing the limitations of existing methods by using controlled fluid pulses to alleviate vitreomacular adhesion and treat retinal detachment without causing significant shear stress.

Implementation Method 1

a pump system coupled to the proximal end of the flexible elongate member and to the fluid reservoir, and configured to pressurize the fluid to a pressure suitable for separating a first body tissue from a second body tissue

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS10507134B2Systems and methods for pulsed posterior vitreous detachment creation

Publication Date: 2019.12.17 ALCON INC

AI summary

This disclosure relates to a tissue separation system to separate the posterior vitreous cortex from the inner limiting membrane in the eye, and to the separation of other body tissues. A system includes a flexible elongate member having a proximal end and a distal end. The flexible elongate member is coupled to a fluid reservoir and has a lumen configured to deliver fluid from the reservoir for use in a surgical procedure and further includes a pump system coupled to the proximal end of the flexible elongate member and to the fluid reservoir, configured to pressurize the fluid to a pressure suitable for separating tissues. The system also includes a control system arranged to control the pump system to provide a series of pulses of fluid through the flexible elongate member and out from the distal end thereof to suitably separate the tissues during the surgical procedure.