Cerebrospinal Fluid Shunt with Sustained Anti-occlusion Agent Delivery

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Solution Overview

Problem

Hydrocephalic shunts often experience occlusion due to tissue proliferation and immune responses, leading to ineffective drainage of cerebrospinal fluid, with approximately 40% failing within 5 years due to tissue growth into the shunt lumen.

Innovation Solution

A biocompatible medical shunt with a long-term delivery system for occlusion-resistant materials, such as rapamycin, is designed to prevent occlusion by incorporating a source of these agents at the proximal and distal ends, utilizing a biocompatible elastomer material and absorptive surfaces to minimize tissue attachment and blockage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a hydrocephalic shunt is implanted to drain cerebrospinal fluid, then fluid drainage function is improved, but tissue proliferation into the shunt lumen occurs causing occlusion

Engineering Contradiction:

Improvefluid drainage functionVSAvoidocclusion resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The shunt is pre-loaded with occlusion-resistant agents (such as dexamethasone sodium phosphate, proteases, or other bioactive substances) before implantation. These agents are incorporated into the shunt structure in advance to prevent tissue proliferation and occlusion from occurring after implantation, thereby maintaining reliability while preserving drainage function.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Bioactive substances serve as intermediaries between the shunt and the surrounding tissue. These substances (including corticosteroids, proteases, and other pharmacological agents) mediate the interaction by preventing tissue adhesion and proliferation, thus protecting the shunt lumen from occlusion while allowing the shunt to perform its drainage function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Duration of action of stationary object

If the shunt remains implanted for the lifetime of the patient, then long-term functionality is improved, but occlusion occurs due to chronic immune response and tissue growth

Engineering Contradiction:

Improveimplant durationVSAvoidocclusion resistance

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The shunt incorporates agents that change the local biochemical parameters around the shunt over time. These agents (such as sustained-release corticosteroids or proteases) continuously modify the tissue environment to prevent fibrosis and cellular proliferation, thereby maintaining occlusion resistance throughout the lifetime of the implant.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The shunt provides continuous delivery of occlusion-resistant agents throughout its entire implantation period. This continuous action ensures that the protective effect against tissue proliferation and occlusion is maintained consistently over the lifetime of the patient, rather than being limited to a short initial period.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If anti-inflammatory agents are loaded on the catheter tip, then encapsulation prevention is improved, but the duration of protection is limited

Engineering Contradiction:

Improveencapsulation preventionVSAvoidprotection duration

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The shunt incorporates a sustained-release mechanism that periodically delivers anti-inflammatory agents over an extended period. This periodic action ensures continuous protection against encapsulation and tissue proliferation, extending the duration of protection from a short initial period to the lifetime of the implant.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The shunt is self-sustaining by incorporating a reservoir or matrix that continuously releases occlusion-resistant agents without requiring external intervention. This self-service mechanism ensures long-term protection against encapsulation and occlusion throughout the entire implantation period.

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

The shunt effectively resists occlusion for the lifetime of the implant, reducing the frequency of blockages and extending the device's functionality, potentially up to 10 years or the patient's lifetime, by maintaining a consistent delivery of occlusion-resistant agents.

Implementation Method 1

utilizing a biocompatible elastomer material and absorptive surfaces to minimize tissue attachment and blockage

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS11623073B2Cerebrospinal fluid shunt having long term anti-occlusion agent delivery

Publication Date: 2023.04.11 MEDTRONIC PS MEDICAL INC

AI summary

The invention includes a shunt for at least partial implantation into a patient that includes an elongated conduit having at least one lumen therethrough, that includes a proximal end for receipt of bodily fluids for flow through the shunt and a distal end for discharge of the bodily fluids from the shunt, and a long term source of at least one occlusion resistant agent, wherein said at least a portion of the at least one occlusion resistant agent can permeate through at least a portion of the elongated conduit. The invention also includes kits and systems.