Helical Electrode Arrangements for Selective Nerve Stimulation
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Solution Overview
Problem
Current implantable medical leads face challenges in selectively targeting nerve fascicles due to the unpredictable alignment of fascicles within nerves, leading to undesired motor side effects during pain treatment.
Innovation Solution
The development of implantable medical leads with helical electrode configurations along the distal end portion, allowing for selective application of electrical signals by overlapping and offsetting electrodes to ensure that any circumferential line intersects at least one electrode, thereby improving the likelihood of capturing desired nerve fascicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electrode configurations are used, then the lead structure is simple, but the selective targeting of nerve fascicles is difficult
Solution Approach 1:
The electrode array is segmented into multiple discrete helical electrodes spaced along the lead shaft, allowing independent control of each electrode to selectively target specific fascicles. This segmentation enables precise spatial control of electrical stimulation to differentiate between adjacent nerve fascicles.
Solution Approach 2:
The electrodes are arranged helically around the lead shaft, adding a circumferential dimension to the longitudinal lead structure. This three-dimensional helical arrangement creates distinct electrical field zones that can selectively engage specific fascicles based on their spatial location around the nerve.
2Object-affected harmful factors
If broad targeting of nerve is used, then the treatment is simpler, but undesired motor side effects occur
Solution Approach 1:
Different regions of the nerve are differentiated by local electrical field properties. The helical electrode arrangement creates localized stimulation zones that can be independently activated to target specific fascicles containing afferent fibers while avoiding efferent fibers, thereby eliminating motor side effects.
Solution Approach 2:
The system dynamically selects which helical electrodes to activate based on real-time feedback and treatment requirements. This dynamic control allows the system to adaptively target specific fascicles during pain treatment while avoiding stimulation of motor-containing fascicles.
3Reliability
If helical electrodes are arranged to ensure circumferential coverage, then the selective capture of fascicles is improved, but the device complexity increases
Solution Approach 1:
Multiple helical electrodes are merged into a continuous or near-continuous helical wraparound configuration, where adjacent electrodes are positioned close together to create overlapping electrical fields. This merging ensures comprehensive circumferential coverage of the nerve, maximizing the reliability of fascicle capture while maintaining a relatively simple overall structure.
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 enhances the selective stimulation of afferent fibers, reducing motor side effects and improving the effectiveness of pain treatment through precise targeting of nerve fascicles, making it suitable for peripheral nerve stimulation.
Implementation Method 1
Electrical signals generated by the devices may be delivered to the tissue of a patient via one or more electrodes disposed at a distal end portion of a medical lead
Data Source
AI summary
A medical lead includes a lead body having a proximal end for electrical connection to an implantable electric signal generator and a distal end portion having a plurality of electrodes extending in a helical manner longitudinally along the distal end portion. Adjacent helical electrodes may be offset, for example, 90 degrees or 180 degrees. The helical electrodes may extend less than, greater than, or 360 degrees. The electrode arrangement provides increased surface area, improving the capability of positioning the lead against the nerve as desired.