Extra-Vascular Electrode Lead Strain Relief
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Solution Overview
Problem
Existing electrode leads for implantable medical devices, particularly extra-vascular leads, face challenges in providing reliable strain relief and securing electrical conductors to individual electrodes without causing mechanical or electrical damage to nerves, as they can lead to abrasion, swelling, and axonal degeneration due to inadequate anchoring and movement-related stress.
Innovation Solution
The design incorporates a dual connection structure for the extra-vascular electrode lead body, with a first anchor point that moves in concert with the body part and a second anchor point that is independent of its movement, offset to provide strain relief and secure the lead body to the body, using suture pads or similar mechanisms to distribute stress and prevent direct strain on the electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single anchor point is used to secure the lead body, then the electrode assembly can be fixed in position, but mechanical stress and movement-related strain are concentrated on the electrode-nerve interface, causing abrasion, swelling, and axonal degeneration
Solution Approach 1:
The patent divides the anchoring function into two separate connection structures: a first connection structure that anchors the lead body to tissue that moves with the nerve, and a second connection structure that anchors the lead body to tissue that is relatively independent of nerve movement. This segmentation distributes mechanical stress away from the electrode-nerve interface, preventing the concentrated strain that causes abrasion, swelling, and axonal degeneration.
Solution Approach 2:
The patent introduces an intermediary anchoring mechanism where the lead body is secured to surrounding tissue through suture pads or similar mechanisms rather than directly to the nerve. This intermediary anchoring system absorbs and distributes mechanical forces, preventing direct transmission of stress to the vulnerable electrode-nerve interface while maintaining lead stability.
2Reliability
If the lead body is rigidly secured to prevent movement, then strain relief is improved, but the electrode assembly may cause compressive force on the nerve when the nerve swells or moves
Solution Approach 1:
The patent employs dynamic anchoring where the first connection structure anchors to tissue that moves with the nerve, allowing the lead to move dynamically with nerve swelling and pulsation. This dynamic configuration prevents compressive forces from building up against the nerve while maintaining adequate strain relief through the offset between anchor points.
3Strength
If the first and second anchor locations are placed close together, then the lead body is securely anchored, but strain relief for the electrode assembly is reduced
Solution Approach 1:
The patent applies local quality by differentiating the functional characteristics of the two anchor points: the first anchor location is positioned to move with the nerve for local compliance, while the second anchor location is positioned in relatively independent tissue for stable anchoring. The offset distance between these differently characterized anchor points creates the necessary strain relief loop without compromising overall anchoring strength.
Data Source
AI summary
Connection structures on an extra-vascular electrode lead body improve strain relief and strengthen the transition region where electrical conductors carried by the lead body are joined to individual electrodes at the distal end of the lead. The electrodes include structure or mechanisms for externally securing the electrode assembly to a body part. A first connection structure is located on the lead body proximal the electrodes to anchor the lead body to a first anchor location in the body that generally moves in concert with the body part. A second connection structure is located on the lead body proximal to the first connection structure to anchor the lead body to a second anchor location that is at least partially independent of movement of the body part. The first and second anchor location are offset by a distance that is less than a distance between the first and second connection structures to provide strain relief for the electrodes.