Helical Electrode Fixation for Stable Tissue Contact
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Solution Overview
Problem
Existing electrode assemblies for implantable medical devices face challenges in achieving stable and intimate contact with tissue, particularly in providing efficient fixation and effective stimulation therapy, as conventional helical structures may not suffice for all types of implant sites.
Innovation Solution
The design incorporates a fixation member with a tissue engaging portion extending along a circular path, combined with a helical structure and a piercing distal tip, allowing both to engage within tissue when the device is rotated, along with a bipolar pace-sense pair configuration for enhanced contact and stimulation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional helical structure is used for fixation, then the device can be implanted, but stable and intimate contact with tissue is not achieved
Solution Approach 1:
The patent combines the helical fixation structure and the electrode surface into a single integrated component. The helical structure itself forms the electrode surface, eliminating the need for separate fixation members and electrode components. This merging provides both mechanical fixation and electrical contact simultaneously, achieving stable intimate contact with tissue while simplifying the overall device structure.
Solution Approach 2:
The helical structure serves multiple functions: it provides mechanical fixation by screwing into tissue, creates intimate contact with the tissue surface, and simultaneously acts as the electrode surface for stimulation and sensing. This multi-functionality resolves the contradiction by achieving reliable tissue contact without adding separate fixation mechanisms.
2Use of energy by moving object
If electrode surface is formed directly on helical structure, then fixation is adequate, but energy utilization is not minimized
Solution Approach 1:
The patent applies different surface characteristics to different regions of the helical structure. The electrode surface is formed with specific material properties (such as conductive coatings) optimized for electrical stimulation and sensing, while the helical structure itself provides mechanical engagement. This local differentiation allows energy-efficient electrical contact while maintaining fixation stability.
3Volume of moving object
If a compact capsule design is used, then device size is reduced, but implantation at various sites becomes more difficult
Solution Approach 1:
The patent segments the implantable device into a compact hermetically sealed capsule containing the pulse generator and power source, with the electrode assembly as a separate but directly coupled component. This segmentation allows the capsule to be miniaturized for reduced device size while the electrode assembly can be configured to accommodate various implantation sites and tissue types.
Data Source
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AI summary
A fixation member of an electrode assembly for an implantable medical device includes a tissue engaging portion extending along a circular path, between a piercing distal tip thereof and a fixed end of the member. The circular path extends around a longitudinal axis of the assembly. A helical structure of the assembly, which includes an electrode surface formed thereon and a piercing distal tip, also extends around the longitudinal axis and is located within a perimeter of the circular path. The tissue engaging portion of the fixation member extends from the distal tip thereof in a direction along the circular path that is the same as that in which the helical structure extends from the distal tip thereof. The electrode assembly may include a pair of the fixation members, wherein each tissue engaging portion may extend approximately one half turn along the circular path.