Foldable Electrode Array for Spinal Cord Stimulation

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Solution Overview

Problem

Current electrode arrays for spinal cord stimulation have limited spatial resolution and require invasive surgical procedures for implantation, leading to inefficiencies in pain management due to imprecise targeting and potential for unnecessary nerve stimulation.

Innovation Solution

A foldable electrode array with a curved, superelastic frame and densely packed electrodes arranged in rows and columns, allowing for precise placement and adjustment of current flow paths to optimize therapeutic effects while minimizing side effects, and can be deployed minimally invasively through a cannula.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrode arrays are densely packed to improve spatial resolution, then therapeutic targeting precision is improved, but the complexity of implantation procedure increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidimplantation procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The electrode array is divided into multiple independently controllable electrode groups or segments along the array. This segmentation allows the system to activate only specific regions as needed, achieving high spatial resolution and selective nerve targeting without requiring the entire dense array to be implanted and activated, thereby reducing implantation complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The electrode array is designed with a collapsible or nested structure that allows the dense electrode configuration to be compressed into a smaller form factor for implantation. The electrodes and connections are arranged in a nested or folded configuration that can be introduced through a minimally invasive catheter, then deployed to achieve the full dense configuration post-implantation.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Stability of the object's composition

If electrode arrays are made more invasive to ensure stable placement, then positioning stability is improved, but patient trauma and procedural risk increase

Engineering Contradiction:
Improvepositioning stabilityVSAvoidpatient trauma
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The electrode array is designed with a curved or flexible configuration that can conform to the anatomical contours of the spinal cord or target tissue. This curved design allows the array to be introduced through a minimally invasive catheter while maintaining stable contact with the tissue surface, eliminating the need for invasive anchoring mechanisms.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The electrode array utilizes a flexible substrate or thin-film construction that allows the device to be introduced through a small catheter and then deployed to conform to the target tissue surface. The flexibility enables minimally invasive delivery while the ability to conform to anatomical surfaces provides stable positioning without requiring traumatic anchoring.

Inventive Principle:
Principle #30Flexible shells and thin films

3Area of stationary object

If current flow paths are expanded to cover larger tissue areas, then therapeutic coverage is improved, but selectivity for target nerves decreases

Engineering Contradiction:
Improvetherapeutic coverage areaVSAvoidnerve targeting selectivity
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The electrode array employs independent control of different electrode segments or groups, allowing the system to activate only specific local regions as needed. This local quality control enables the therapist to target specific nerve roots or spinal cord segments while keeping adjacent areas inactive, achieving high selectivity even with a large overall array coverage area.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The array is divided into multiple independently controllable electrode groups that can be activated selectively. This segmentation allows current to be confined to specific anatomical regions by activating only the relevant electrode segments, maintaining high targeting selectivity while the physical array spans a large area for comprehensive coverage capability.

Inventive Principle:
Principle #1Segmentation

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 electrode array provides improved spatial resolution and stability, allowing for more targeted and efficient delivery of therapeutic currents with reduced side effects and invasive procedures, enhancing pain management outcomes.

Implementation Method 1

the frame can be folded without sustaining substantial permanent deformation and, once unfolded, returns to its unfolded, curved, profile

Methodology Applied
Scientific EffectSuperelasticity: Pseudoelasticity

Data Source

PatentEP2249919B1Foldable, implantable electrode array assembly
Publication Date: 2019.05.22 STRYKER CORP
  • EP2249919B1 patent drawingFigure 1
  • EP2249919B1 patent drawingFigure 2
  • EP2249919B1 patent drawingFigure 2A

AI summary

An electrode array assembly (28) with a frame that is foldable or bendable (32) on which electrodes (36) are disposed. The frame includes tabs (55) that are spaced from adjacent portions of the frame; the electrodes are disposed on the tabs.