Lubricious Coating for Implantable Medical Device Tissue Friction

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Solution Overview

Problem

Implantable medical devices (IMDs) face challenges due to their rigid housing, which limits their implantation locations within the body, often requiring long leads that increase surgical complexity, risk of infection, and tissue erosion, especially when implanted near the brain, where friction and movement can cause device displacement and erosion.

Innovation Solution

The use of a lubricious material on the external surface or impregnated in the housing or member of the IMD to reduce friction between the device and tissue, allowing for smoother implantation and reducing the risk of skin erosion and infection, with embodiments including elastomeric materials like silicone and non-elastomeric materials such as polysulfone and polyurethane.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid housing is used for the IMD, then the device can be hermetically sealed and protect internal components, but the device cannot be implanted in certain locations and may cause tissue erosion and friction

Engineering Contradiction:

Improvehermetic sealingVSAvoidtissue erosion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies a flexible lubricious coating layer on the external surface of the rigid IMD housing. This coating acts as a flexible interface between the rigid device and surrounding tissue, reducing friction and preventing tissue erosion while maintaining the hermetic sealing properties of the rigid housing underneath.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure by combining a rigid hermetic housing material (such as titanium or plastic) with a lubricious coating material (such as silicone, polyurethane, or PTFE). This composite approach allows the device to simultaneously achieve hermetic sealing from the rigid housing and reduced friction/tissue protection from the lubricious coating layer.

Inventive Principle:

Principle #40Composite materials

2Length of moving object

If the IMD is implanted closer to the therapy site, then lead length is reduced and surgical complexity is minimized, but friction and movement cause device displacement and erosion

Engineering Contradiction:

Improvelead lengthVSAvoiddevice displacement

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The lubricious coating on the IMD housing creates a low-friction interface with surrounding tissue, allowing the device to be positioned closer to the therapy site without causing tissue erosion or device displacement. This enables shorter leads while maintaining device stability and reducing surgical complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

3Volume of moving object

If the IMD housing is made smaller, then implantation locations are expanded, but the housing may not accommodate all necessary components

Engineering Contradiction:

Improvehousing volumeVSAvoidcomponent accommodation

Core Design Contradiction:

Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The lubricious coating allows the IMD to be implanted in smaller, more accessible anatomical locations without causing tissue damage. This enables the use of smaller housing volumes while still accommodating necessary components and reducing the need for long leads extending to distant therapy sites.

Inventive Principle:

Principle #30Flexible shells and thin films

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 lubricious material facilitates easier insertion and reduces post-implantation friction, minimizing the risk of skin erosion and infection, enabling IMDs to be implanted closer to the therapy or monitoring site with shorter leads, improving surgical outcomes and patient safety.

Implementation Method 1

a lubricious material on the external surface or impregnated in the housing or member of the IMD to reduce friction between the device and tissue

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS9162072B2Implantable medical device with lubricious material

Publication Date: 2015.10.20 MEDTRONIC INC

AI summary

An implantable medical device with lubricious material permits implantable medical devices to have a reduced friction between the device and at least a portion of the surrounding tissue. The implantable medical device may have a housing or it may have a housing and a member for providing a smooth interface between the device and the tissue. The lubricious material may be provided on or impregnated in the housing or the member. In some embodiments, the device is configured for implantation in the head of a human body. In other embodiments, the device is configured for implantation between the cranium and the scalp. In some embodiments, the device includes a single module while in other embodiments a plurality of modules are coupled together to provide a smaller profile.