Virtual Target Pole Adjustment for Dorsal Root Trajectory

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Solution Overview

Problem

Current Spinal Cord Stimulation (SCS) systems face challenges in determining optimal stimulation parameters due to uncertainties in electrode placement and the complex electrical environment within the spinal column, making it difficult to deliver effective therapy for chronic pain management.

Innovation Solution

A system that includes a neurostimulator connected to implantable electrodes and an external device capable of determining the trajectory of dorsal roots by measuring neural responses, such as evoked compound action potentials, to adjust electrode configurations and ensure the stimulation field is parallel to the dorsal root trajectory, thereby optimizing stimulation therapy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional SCS systems use fixed electrode configurations, then device simplicity is maintained, but stimulation effectiveness is reduced due to uncertainties in electrode placement and inability to align with dorsal root trajectory

Engineering Contradiction:
Improvestimulation effectivenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary determination of dorsal root trajectory and electrode configuration optimization before actual stimulation therapy. The external device calculates the optimal electrode configuration based on measured neural responses and predetermined anatomical data, storing this configuration for subsequent therapy delivery. This preliminary setup ensures stimulation effectiveness is maximized from the start without requiring complex real-time adjustments during therapy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system measures neural responses (such as evoked compound action potentials) at multiple electrode locations and uses this feedback to determine the optimal electrode configuration. The external device receives neural response data, compares it against predetermined dorsal root trajectory information, and adjusts the electrode configuration accordingly. This feedback loop ensures reliable and effective stimulation by continuously optimizing electrode placement based on actual neural responses.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If electrode configuration is adjusted to align with dorsal root trajectory, then stimulation precision is improved, but measurement and detection difficulty increases

Engineering Contradiction:
Improvedorsal root trajectory measurementVSAvoidneural response measurement complexity
Core Design Contradiction:
Measurement precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The system obtains predetermined information about dorsal root trajectory and anatomical landmarks before performing measurements. This preliminary data serves as a reference framework that guides the measurement process, allowing the system to compare measured neural responses against known anatomical patterns. This preparation simplifies the measurement process by providing expected values and patterns to guide the detection of actual neural responses.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The external device acts as an intermediary that processes the complex neural response measurements and translates them into meaningful trajectory information. Rather than requiring direct complex measurements of the dorsal root trajectory, the system measures neural responses and uses the external device to interpret these responses in the context of predetermined anatomical data. This intermediary processing reduces measurement difficulty by working with more accessible neural response signals.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple neural response measurements are taken to determine trajectory, then measurement accuracy is improved, but time consumption increases

Engineering Contradiction:
Improvetrajectory determination accuracyVSAvoidsetup time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system obtains predetermined information about dorsal root trajectory and anatomical characteristics before the measurement process. This preliminary data allows the system to focus measurements on specific key locations and compare results against known patterns, rather than requiring exhaustive measurements across all possible locations. The predetermined information serves as a reference that accelerates the determination process while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system measures neural responses at multiple electrode locations, but uses predetermined trajectory information to identify which measurements are most critical for accurate determination. Rather than requiring equally detailed measurements everywhere, the system focuses measurement efforts on locations that provide the most information for trajectory determination, based on the predetermined anatomical framework. This selective measurement approach reduces time while maintaining precision.

Inventive Principle:
Principle #16Partial or excessive 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 approach allows for personalized and effective spinal cord stimulation by aligning the stimulation field with the dorsal root trajectory, improving pain management by ensuring the correct activation of neural elements and maintaining consistent stimulation intensity.

Implementation Method 1

Implantable stimulation devices deliver electrical stimuli to nerves and tissues for the therapy of various biological disorders

Methodology Applied
Scientific EffectElectrical stimulation: Electric Field

Implementation Method 2

determine a trajectory of each of one or more dorsal roots by measuring a neural response, such as an evoked compound action potential, to the stimulation at each of the plurality of sample stimulation locations

Methodology Applied
Scientific EffectEvoked compound action potential:

Data Source

PatentEP3536374B1Virtual target pole adjustment based on nerve root trajectory
Publication Date: 2022.06.29 BOSTON SCI NEUROMODULATION CORP
  • EP3536374B1 patent drawingFigure 1~2
  • EP3536374B1 patent drawingFigure 3
  • EP3536374B1 patent drawingFigure 4

AI summary

Techniques for determining the trajectory of a one or more dorsal roots and utilizing the trajectories to improve a spinal cord stimulation model are disclosed. A first improvement constructs a target stimulation field along a path that is parallel with the determined trajectory that is nearest to a specified desired location of stimulation. An allocation of stimulation among the electrodes to mimic the target field is computed. A second improvement models a response of neural elements at evaluation positions that are parallel with the trajectories based on the electric field that is generated for the computed allocation of stimulation among the electrodes. The stimulation amplitude is adjusted based on the neural element modeling to maintain stimulation intensity, and the stimulation amplitude and allocation of stimulation among the electrodes are compiled into an electrode configuration that is communicated to a neurostimulator.