Percutaneous Lead With Optical Fiber Coupling for Stable SCS Signals

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Solution Overview

Problem

Existing spinal cord stimulation systems face challenges with inaccurate lead coupling during optical reflectometry, leading to unstable optical signals, device erosion, and prolonged recharge times, which affect the precision and longevity of spinal cord stimulation treatments.

Innovation Solution

The design incorporates a non-metallic IPG case with a super ellipse shape to reduce erosion, uses canted coil connector springs for stable lead fixation, and employs a non-metallic case for inductive charging to minimize eddy currents, along with a hermetically sealed ceramic or glass casing to maintain biocompatibility and optical integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If percutaneous lead arrays are used with multiple cylindrical electrode contacts, then spinal cord stimulation can be achieved, but lead coupling accuracy deteriorates leading to unstable optical signals

Engineering Contradiction:

Improveoptical signal stabilityVSAvoidlead coupling accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an optical fiber as an intermediary element that transmits light signals between the IPG and the spinal cord stimulation system. This optical intermediary enables precise measurement of lead coupling accuracy through optical reflectometry, allowing the system to detect and compensate for coupling variations, thereby stabilizing the optical signals while maintaining accurate lead positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If metal IPG case is used for structural strength, then device durability is improved, but eddy currents are generated during inductive charging causing heating and reduced charging efficiency

Engineering Contradiction:

ImproveIPG case durabilityVSAvoidcharging efficiency

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The patent replaces the traditional metal IPG case with a non-metallic material (such as biocompatible polymer or ceramic). This substitution eliminates the generation of eddy currents during inductive charging, as non-metallic materials do not conduct electricity. The non-metallic case maintains sufficient structural strength and durability while allowing efficient wireless charging without energy loss to eddy currents or harmful heating.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Duration of action of stationary object

If standard lead fixation methods are used, then lead attachment is achieved, but device erosion occurs over time affecting long-term implant stability

Engineering Contradiction:

Improveimplant stabilityVSAvoiddevice erosion

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs composite materials for the IPG case, combining biocompatible polymers with reinforcement elements or coating layers that resist tissue erosion. The composite structure provides both the necessary mechanical strength for long-term stability and resistance to degradation from surrounding tissues. This may include using medical-grade silicones, polyurethanes, or ceramic-composite materials that resist erosion while maintaining flexibility and biocompatibility.

Inventive Principle:

Principle #40Composite materials

4Measurement precision

If optical reflectometry is implemented for precise stimulation, then stimulation accuracy is improved, but recharge time is prolonged due to signal processing requirements

Engineering Contradiction:

Improvestimulation accuracyVSAvoidrecharge time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements preliminary calibration of the optical reflectometry system during the initial implantation procedure. The lead coupling characteristics are measured and stored in memory before clinical use. During subsequent operations, the system uses these pre-established parameters to quickly assess coupling status without requiring extensive real-time signal processing, thereby reducing recharge time while maintaining high stimulation accuracy.

Inventive Principle:

Principle #10Preliminary action

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

This configuration stabilizes optical signals, reduces device erosion, and enables continuous charging, thereby enhancing the accuracy and longevity of spinal cord stimulation treatments while minimizing tissue degradation and recharge time.

Implementation Method 1

uses canted coil connector springs for stable lead fixation, and employs a non-metallic case for inductive charging to minimize eddy currents

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

employs a hermetically sealed ceramic or glass casing to maintain biocompatibility and optical integrity

Methodology Applied

Scientific EffectHermetic sealing:

Data Source

PatentUS12478780B2Electrode and percutaneous lead and method of use

Publication Date: 2025.11.25 WAVEGATE CORP

AI summary

A percutaneous lead is provided which includes a generally tubular, multi-duct, flexible lead body. The lead body supports a distal set of electrodes and a proximal set of contacts which are connected by conductors in the ducts. The lead body further houses an optical fiber with a side firing section. The side firing section is held adjacent an optical transmission window, integrally formed with the flexible lead body. A cylindrical ferrule is provided to position the fiber in the header of an IPG.