Elastic Fixation Tines for Stable Electrode Contact
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Solution Overview
Problem
Existing implantable medical devices face challenges in securely fixing electrodes to epicardial surfaces for effective stimulation therapy, as current fixation methods may not ensure consistent and stable contact with the tissue.
Innovation Solution
An implantable medical device assembly featuring elastically deformable tissue-penetrating fixation tines, formed from super-elastic wire, which extend from a mounting structure to securely penetrate the tissue and maintain intimate contact with the electrode, allowing for reliable electrode fixation at the stimulation site.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixation methods are used to secure electrodes to epicardial surfaces, then the electrode can be positioned at the stimulation site, but the fixation is not consistent or stable enough to ensure reliable tissue contact
Solution Approach 1:
The fixation tines are designed to be elastically deformable, transitioning from a compressed delivery state to an extended deployed state. This dynamic transformation allows the tines to adapt to tissue contours and maintain stable fixation through elastic recovery forces, resolving the contradiction between fixation reliability and device complexity by using passive elastic mechanisms rather than complex active fixation systems
Solution Approach 2:
The tines utilize super-elastic material properties that allow significant deformation and recovery. By changing the physical state of the material from compressed to extended, the system achieves reliable fixation without requiring complex mechanical structures, thus improving fixation stability while keeping the device relatively simple
2Reliability
If the electrode is positioned offset from the distal end for optimal stimulation, then the stimulation therapy can be effectively delivered, but the fixation tines must extend beyond the distal end to reach tissue, requiring longer tine segments
Solution Approach 1:
The fixation tines are divided into distinct segments: a mounting segment that attaches to the mounting structure and a tine segment that extends to penetrate tissue. This segmentation allows the electrode to be positioned offset from the distal end for optimal stimulation while the separate tine segment reaches beyond the mounting structure to engage tissue, resolving the contradiction between positioning accuracy and tine length requirements
Solution Approach 2:
The fixation system extends in multiple dimensions: the electrode is positioned laterally offset from the distal end along the mounting structure, while the tines extend distally beyond the mounting structure in a different spatial dimension. This multi-dimensional arrangement allows both optimal electrode positioning and sufficient tine extension to reach tissue
3Reliability
If elastically deformable tines are used to penetrate tissue, then stable fixation is achieved, but the tines must be held in an extended condition during delivery and then released to engage tissue, adding complexity to the delivery process
Solution Approach 1:
The tines are pre-configured in a compressed state within the delivery catheter, ready for deployment. The delivery catheter maintains the tines in this preliminary compressed condition during insertion and positioning, then releases them to allow automatic extension and tissue penetration. This preliminary action resolves the contradiction by preparing the fixation mechanism in advance, making the actual deployment simple and intuitive
4Reliability
If the piercing tips are located distal to the distal end of the mounting structure to penetrate tissue, then effective fixation is achieved, but the tines must extend beyond the structure, requiring the mounting structure to accommodate longer tine segments
Solution Approach 1:
The mounting structure is designed with channels or pathways that accommodate the fixation tines in a nested configuration. The tines are contained within the mounting structure during delivery, then extend outward to penetrate tissue. This nesting approach allows the piercing tips to be located distal to the mounting structure for effective fixation while keeping the overall structure compact and minimizing volume
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 described solution ensures stable and effective fixation of electrodes to the epicardial surface, enhancing the delivery and efficacy of stimulation therapy by maintaining consistent tissue contact and reducing the risk of electrode dislodgment.
Implementation Method 1
Each fixation tine is a component formed from a super-elastic wire
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
An implantable medical device assembly includes a mounting structure, an electrode, and fixation tines. The electrode protrudes from a surface of the structure, offset proximally from a distal end of the structure, and approximately centered between first and second sides of the structure. Each tine extends away from the surface - a first adjacent the first side, and a second adjacent the second side. Each tine is elastically deformable from a relaxed condition, in which the tine extends toward a proximal end of the structure, to an extended condition, in which the tine extends away from the distal end of the structure. A delivery tool has first and second longitudinally extending sidewalls to receive passage of the structure therebetween. When the structure distal end is located between proximal ends of the sidewalls, a rail-like edge of each sidewall receives, and elastically deforms to the extended condition, a corresponding tine.