Elastic Deflection Coupling for Implantable Medical Lead
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Solution Overview
Problem
Implantable medical leads used for electrical stimulation are prone to displacement and damage due to tissue movement, particularly in areas like the spine, where flexion and extension cause tension and compression forces that can lead to lead failure or migration.
Innovation Solution
Incorporating an elastic deflection component, such as a helical spring, between the lead body conductor and the electrode at the distal end of the lead, which electrically connects the conductor to the electrode and reduces the transfer of tension and compression forces, thereby minimizing the risk of lead failure or migration during spinal flexion and extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid lead structure is used to ensure electrical connection stability, then electrical connection reliability is improved, but the lead becomes susceptible to damage from spinal flexion and extension forces
Solution Approach 1:
The lead incorporates a dynamic spring mechanism that allows controlled movement and deflection. The spring can compress and extend to accommodate spinal flexion and extension, transforming the rigid structure into a dynamic one that adapts to mechanical stresses while maintaining electrical connectivity.
Solution Approach 2:
The spring component changes its physical parameters (length, compression) in response to mechanical forces. When the spine flexes or extends, the spring compresses or extends accordingly, changing its dimensional parameters to absorb mechanical energy while maintaining the electrical connection between the lead and electrode.
2Strength
If the lead is made flexible to accommodate spinal motion, then resistance to mechanical damage is improved, but electrical connection stability may be compromised
Solution Approach 1:
The spring provides controlled flexibility through its dynamic mechanical properties. It allows the lead to flex and move with spinal motion while its coiled structure inherently maintains continuous electrical contact, preventing disconnection even during significant deflection.
Solution Approach 2:
The lead employs a composite structure combining conductive materials (for electrical connectivity) with elastic spring materials (for mechanical flexibility). This composite design integrates both electrical and mechanical functions into a single component that simultaneously provides conductivity and shock absorption.
3Strength
If a spring mechanism is added to reduce force transfer, then resistance to mechanical damage is improved, but device complexity increases
Solution Approach 1:
The spring is integrated directly into the lead structure itself, merging the mechanical shock-absorption function with the electrical conduction function. Rather than adding a separate complex mechanism, the spring forms part of the lead's structural backbone, combining multiple functions in a single simplified design.
Solution Approach 2:
The spring utilizes a helical coil geometry that provides flexibility and shock absorption through its curved, thin-wire structure. This flexible geometric form factor allows the spring to deflect and compress easily, providing mechanical protection without requiring bulky or complex components.
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
The elastic deflection component increases the flexibility and robustness of the lead, allowing it to accommodate spinal motion without damage or migration, reducing mechanical failure rates and ensuring a secure attachment to the target tissue across varying anatomical curvatures and movements.
Implementation Method 1
The spring may include a helical spring. The helical spring may include an end region that is more tightly coiled than an intermediate region of the helical spring.
Data Source
AI summary
An implantable medical lead may include a lead body, a substrate, and an elastic deflection component. The lead body includes a proximal end configured to couple to an implantable pulse generator, a distal end opposite the proximal end, and an electrical conductor extending through the lead body. The substrate is at the distal end and supports an array of electrodes. The elastic deflection component physically and electrically connects the electrical conductor and an electrode of the array of electrodes. The elastic deflection component is configured to compensate for at least one of tension forces or compression forces transferred from the electrical conductor to the electrode of the array of electrodes.