Pre-molded Cylindrical Sub-assemblies for Implantable Medical Leads
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Solution Overview
Problem
Existing implantable medical leads face challenges in protecting elongated conductors during assembly, leading to potential damage and low impedance conditions, which can affect the performance and reliability of electrical stimulation therapy.
Innovation Solution
The use of pre-molded cylindrical sub-assemblies with a conductive element and an insulative element molded onto the interior surface, which centers and protects the conductors, preventing damage and ensuring proper electrical connections, thereby enhancing the mechanical properties and AC impedance of the leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional assembly methods are used without pre-molded sub-assemblies, then manufacturing flexibility is maintained, but conductor protection is insufficient leading to damage and low impedance conditions
Solution Approach 1:
The insulative element is pre-molded onto the cylindrical conductive element before assembly, creating a pre-molded cylindrical sub-assembly that centers and protects the elongated conductor during insertion. This preliminary action prevents conductor damage and low impedance conditions that would otherwise occur during assembly.
Solution Approach 2:
The lead assembly is divided into modular pre-molded cylindrical sub-assemblies, each containing a cylindrical conductive element with an insulative element molded onto its interior surface. This segmentation allows for standardized protective units that can be assembled systematically, improving both conductor protection and manufacturing efficiency.
2Ease of manufacture
If conductors are exposed during assembly, then manufacturing process is simpler, but conductor damage occurs leading to low impedance conditions
Solution Approach 1:
The insulative element acts as an intermediary component between the cylindrical conductive element and the elongated conductor. It provides a protective interface that centers the conductor within the lumen and prevents direct contact that could cause damage, while still allowing for straightforward assembly processes.
3Reliability
If insulative element extends entire longitudinal length, then conductor protection is maximized, but material usage and complexity increase
Solution Approach 1:
The insulative element is strategically positioned to extend only along specific portions of the cylindrical conductive element where conductor protection is most critical, rather than covering the entire longitudinal length. This local quality approach provides adequate protection while optimizing material usage and reducing unnecessary complexity.
Data Source
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AI summary
Pre-molded cylindrical sub-assemblies for inclusion in an implantable medical lead are described. The pre-molded cylindrical sub-assemblies comprise a cylindrical conductive element formed from a conductive material to define a substantially continuous interior surface and a substantially continuous exterior surface, and an insulative element formed from an insulative material molded onto the interior surface of the cylindrical conductive element. An interior surface of the insulative element defines a lumen of the pre-molded cylindrical sub-assembly configured to receive one or more elongated conductors of the implantable medical lead, and the cylindrical conductive element is configured to be electrically connected to one of the elongated conductors with the elongated conductors within the lumen. The cylindrical conductive element may act as an electrode, e.g., on a distal portion of the lead, or a connector, e.g., on a proximal portion of the lead.