Segmented Neurostimulation Lead Impedance Positioning

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Solution Overview

Problem

Current implantable neurostimulation systems face challenges in precisely determining the location and orientation of segmented circumferential electrodes relative to target tissue, particularly in spinal cord stimulation, due to the limitations of imaging tools which cannot accurately show the position of electrodes relative to soft tissue like the spinal cord.

Innovation Solution

The method involves measuring the impedance of each electrode on a neurostimulation lead, determining the impedance difference, and re-positioning the lead based on this comparison to ensure correct placement relative to the target tissue, using an impedance monitor and processor to suggest adjustments such as displacement or rotation to achieve optimal positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If imaging tools are used to guide lead placement, then the placement process can be visualized, but the imaging tools cannot accurately show the position of electrodes relative to soft tissue like the spinal cord

Engineering Contradiction:

Improveelectrode position measurement precisionVSAvoidsoft tissue position detection difficulty

Core Design Contradiction:

Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces mechanical/imaging-based positioning systems with an electrical impedance-based detection system. By measuring impedance values between electrodes and using these to calculate lead position and orientation relative to the spinal cord, the system overcomes the limitation of imaging tools that cannot visualize soft tissue positions accurately.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If segmented circumferential electrodes are used on the lead, then more precise stimulation targeting is possible, but the ability to determine lead orientation and electrode-tissue proximity becomes more difficult

Engineering Contradiction:

Improvestimulation targeting precisionVSAvoidlead orientation detection difficulty

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs feedback by measuring impedance values between the segmented circumferential electrodes and using these measurements to determine lead orientation and electrode-tissue proximity. The system continuously monitors impedance changes and uses this feedback information to calculate precise positioning data, enabling both versatile stimulation targeting and accurate orientation determination.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If impedance measurements are taken to determine electrode position, then precise placement can be achieved, but additional measurement and processing steps are required

Engineering Contradiction:

Improveelectrode placement precisionVSAvoidmeasurement and processing system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent makes the neurostimulator device multi-functional by enabling it to perform both its primary function of delivering electrical stimulation and the secondary function of measuring impedance and calculating lead position. This integration eliminates the need for separate measurement devices and reduces overall system complexity while achieving precise electrode placement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 approach allows for precise placement of electrodes, enhancing the effectiveness of neurostimulation therapy by ensuring that electrical stimulation is directed to the correct tissue area, thereby improving pain relief outcomes.

Implementation Method 1

measuring an impedance of each of the electrodes

Methodology Applied

Scientific EffectElectrical Impedance: Electrical Resistance

Data Source

PatentUS11064898B2System and method for using impedance to determine proximity and orientation of segmented electrodes

Publication Date: 2021.07.20 BOSTON SCI NEUROMODULATION CORP

AI summary

A method for implanting a neurostimulation lead within a patient includes measuring impedances of electrodes on the lead in order to correctly position the lead relative to a target tissue region. The electrodes are circumferentially segmented electrodes that are spaced from each other about the longitudinal axis of the lead. When the difference between the impedances of the electrodes exceeds a threshold value, the lead is in the correct position. In accordance with another embodiment, impedance measurements are used to select which one of the electrodes is closest to the target tissue region. By determining which electrode has the highest impedance and which electrode has the lowest impedance, the type of tissue adjacent to each electrode can be determined based on the conductivity properties of the tissue. The target tissue region may be a spinal cord, a posterior longitudinal ligament, white matter, or gray matter.