Self-Rolling Nerve Stimulation Sleeve With Stress Gradient

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Solution Overview

Problem

Existing implantable sleeves for stimulating or detecting elongated cylindrical nerves, such as the vagus nerve, face challenges including nerve damage during implantation, anatomical integrity issues post-implantation, manufacturing reproducibility problems, and the generation of virtual electrodes, which complicate the implantation process and affect the accuracy of nerve stimulation.

Innovation Solution

A self-rolling sleeve structure with prestressed elastomer sheets, featuring flared ends and a stress gradient to minimize nerve stress and prevent virtual electrode formation, allowing for efficient and reproducible production and improved anatomical compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a uniform prestressed sleeve is used, then the sleeve maintains tight contact with the nerve, but it causes excessive compression and potential nerve damage

Engineering Contradiction:
Improvecontact stabilityVSAvoidnerve compression damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different prestress levels to different zones of the sleeve. The middle region has higher prestress to maintain tight contact with the nerve, while the edge regions have lower prestress to avoid excessive compression and damage to the nerve tissue. This localized differentiation of mechanical properties resolves the contradiction between maintaining contact stability and preventing compression damage.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the sleeve is made from thin elastomer sheets, then the sleeve is flexible and biocompatible, but manufacturing reproducibility is compromised

Engineering Contradiction:
ImproveflexibilityVSAvoidproduction reproducibility
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The sleeve is manufactured by segmenting the elastomer sheet into multiple zones with different prestress characteristics. This segmentation allows independent control of manufacturing parameters for each zone, enabling reproducible production of the complex stress distribution pattern while maintaining the overall flexibility of the thin elastomer structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs parameter changes in the manufacturing process by applying different prestress levels to different zones of the elastomer sheet. This controlled variation of mechanical parameters during manufacturing enables reproducible production of sleeves with optimized flexibility and stress distribution, resolving the contradiction between thin-sheet flexibility and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the sleeve edges are sharp, then the sleeve structure is simple, but shearing forces and nerve damage occur during implantation

Engineering Contradiction:
Improvesleeve structureVSAvoidshearing forces on nerve
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The sleeve edges are pre-formed with rounded contours during manufacturing, eliminating the need for sharp edges. This preliminary action of shaping the edges before implantation prevents shearing forces and nerve damage while maintaining relative structural simplicity, as the rounding is integrated into the manufacturing process rather than requiring additional complex components.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If the sleeve is tightly wrapped around the nerve, then electrode contact is improved, but virtual electrodes are generated

Engineering Contradiction:
Improveelectrode contact accuracyVSAvoidvirtual electrode generation
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies different prestress levels to different zones of the sleeve to optimize electrode contact while preventing virtual electrode generation. The middle region maintains higher prestress for good electrode-nerve contact, while the edge regions have reduced prestress to minimize stress concentration that would otherwise create virtual electrodes, thus resolving the contradiction between contact accuracy and harmful factor generation.

Inventive Principle:
Principle #3Local quality

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

Facilitates rapid and stress-free implantation, maintains anatomical integrity, suppresses virtual electrode generation, and ensures effective nerve contact, enhancing the reliability and safety of nerve stimulation therapies.

Implementation Method 1

The sheet is prestressed so as to allow it to be self-rolled up, from an initial position where the sheet is held under stress in the expanded state, to a final position where the sheet is freely rolled up in a spiral forming a sleeve around the organ

Methodology Applied
Scientific EffectPrestress: Stress Relaxation

Implementation Method 2

the sheet comprises at least one zone having a stress near the first and/or the second transverse edge on the longitudinal edges lower than the stress of a zone located in a middle region of the sheet so as to create at least one end of the flared sheet

Methodology Applied
Scientific EffectStress distribution: Stress Relaxation

Data Source

PatentEP3389761B1Implantable probe comprising a sleeve, particularly for the stimulation of a nerve, and methods for producing said sleeve
Publication Date: 2021.10.13 SORIN CRM
  • EP3389761B1 patent drawingFigure 1~4
  • EP3389761B1 patent drawingFigure 5~6
  • EP3389761B1 patent drawingFigure 7~11

AI summary

The invention relates to an implantable probe comprising a sleeve that can be wound around a long cylindrical body, said sleeve comprising a film (26) consisting of an elastically deformable material carrying at least one detection/stimulation electrode (28). The film is pre-stressed so as to allow the self-winding thereof from an initial position in which the film is maintained under stress in the deployed state to an end position in which the film is freely wound in a spiral forming a sleeve. In the end position of the sleeve, the film (26) comprises at least one zone which is under less stress close to the first and/or second transverse edge on the longitudinal edges, than a zone located in a central region of the film, in such a way as to create at least one end of the opened film. The invention also relates to a method for producing such a sleeve for an implantable probe.