Spinal Cord Stimulator Lead Offset Detection via Impedance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining the relative position of electrode leads in spinal cord stimulation systems are costly, time-consuming, and inefficient, often requiring medical imaging and significant energy consumption, with limited ability to detect lead shifts and adjust therapy parameters effectively.
Innovation Solution
A method and system that estimate the offset between electrode leads using impedance measurements, pre-conditioning to attenuate noise, and calculating pre-conditioned impedances to determine lead position with improved resolution and accuracy, allowing for early detection of lead shifts without the need for medical imaging or excessive energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If medical imaging methods (radiography, fluoroscopy) are used to determine lead position, then measurement accuracy is improved, but cost and time consumption increase significantly
Solution Approach 1:
The patent replaces mechanical imaging systems (radiography, fluoroscopy) with an electrical measurement system that uses impedance measurements between electrodes to determine lead position. The system measures impedance values between multiple electrode pairs and uses these electrical measurements to calculate lead offset, substituting complex mechanical imaging equipment with simple electrical measurement circuits already present in the implantable device.
Solution Approach 2:
The implantable device performs self-diagnosis by using its own electrodes and impedance measurement capabilities to determine lead position. The device automatically measures impedance between electrode pairs, processes the measurements to detect lead offset, and can trigger alerts without requiring external imaging equipment or hospital visits, enabling the system to monitor itself.
2Measurement precision
If impedance measurements between all inter-lead electrode pairs are taken, then measurement completeness is improved, but memory capacity and battery consumption increase significantly
Solution Approach 1:
The patent segments the set of all possible electrode pair measurements into a smaller, strategically selected subset. Instead of measuring all 64 possible pairs (8 electrodes × 8 electrodes), the system measures only 32 specific pairs that provide sufficient information for lead offset detection. This segmentation reduces the measurement burden while maintaining detection accuracy.
Solution Approach 2:
The patent applies partial action by measuring only the necessary subset of electrode pairs rather than all possible pairs. The 32 selected measurements represent exactly half of all possible combinations, providing sufficient data for lead offset determination while reducing energy consumption and memory requirements by 50% compared to complete measurement sets.
3Device complexity
If impedance measurements with one-electrode resolution are used, then device complexity is reduced, but detection resolution decreases preventing detection of shifts less than one electrode
Solution Approach 1:
The patent uses feedback by comparing impedance measurements from multiple electrode pairs and analyzing the pattern of measurements to determine lead offset. The system processes measurements from 32 electrode pairs and uses the collective information to achieve sub-electrode resolution (¼ electrode), where the combined feedback from multiple measurements enables detection of shifts smaller than any single measurement could detect.
Solution Approach 2:
The patent merges information from multiple impedance measurements to achieve higher resolution. By combining data from 32 different electrode pair measurements and analyzing their collective pattern, the system achieves ¼ electrode resolution, demonstrating how merging multiple lower-resolution measurements can produce higher-resolution information.
4Measurement precision
If electric field measurements are used to detect lead offset, then measurement capability is improved, but energy consumption increases due to requirement of sufficient current amplitudes
Solution Approach 1:
The patent substitutes electric field measurement methods with impedance measurement methods. Instead of using current amplitudes to induce measurable electric fields at non-active electrodes (which consumes significant energy), the system uses impedance measurements that can be performed with much lower current levels, reducing energy consumption while maintaining lead offset detection capability.
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
Enables better management of spinal cord stimulation therapy by detecting lead shifts early, preserving battery life, and reducing memory and energy consumption, with a resolution of ¼ electrode and accuracy of ½ electrode, facilitating effective corrective actions.
Implementation Method 1
measuring Impedances between the electrodes of each selected electrode pair
Data Source
AI summary
A method for estimating an offset between a first group and a second group of contacts with respect to a longitudinal direction. Each group of contacts includes a plurality of electrodes arranged along a surface of a body of a lead. The method includes the steps of: (a) Selecting a number of electrode pairs, each electrode pair including an electrode of the first contact group and an electrode of the second contact group, and measuring the impedances between the electrodes of each selected electrode pair; (b) pre-conditioning the measured impedances for attenuating unwanted noise to generate pre-conditioned impedances, and (c) determining the lead offset using the pre-conditioned impedances.