Welded Septum Assembly for Implantable Device Seal Integrity
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Solution Overview
Problem
Implantable electronic devices (IEDs) face challenges in maintaining a seal while allowing access to internal components, such as setscrews, to facilitate lead disconnection without compromising the integrity of the electrical and fluid seals within the header assembly.
Innovation Solution
The implementation of a septum assembly within the header body, which includes a retainer and a septum, allows for tool insertion and provides a seal when the tool is not present, with the retainer being ultrasonically or laser-welded to the header body using energy directors and sealing elements to ensure a secure and fluid-tight connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is provided to prevent communication of electrical signals and bodily fluids into the internal cavity of the header, then the electrical and fluid seal integrity is improved, but access to the set screw for lead disconnection is lost
Solution Approach 1:
The header is divided into sealed and accessible segments. The seal isolates the internal cavity containing electrical components from the external environment, while the set screw remains accessible through a designated access point that maintains the overall seal integrity of the header assembly.
Solution Approach 2:
The set screw acts as an intermediary element that provides controlled access to the internal cavity. It allows lead disconnection while maintaining the seal barrier, serving as a mediator between the sealed internal environment and the external access requirement.
2Reliability
If the header is hermetically sealed to prevent fluid ingress, then the device reliability is improved, but the ability to service internal components is reduced
Solution Approach 1:
The header assembly is segmented into sealed protective portions and controlled access portions. Critical electrical components remain protected within the hermetically sealed cavity, while the set screw access point provides a controlled interface for servicing without compromising the overall seal.
Solution Approach 2:
The set screw is pre-positioned and accessible before final sealing operations. This allows lead disconnection and component servicing to be performed on the external portion of the header while maintaining the hermetic seal of the internal cavity throughout the device lifecycle.
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
This solution enables secure access to internal components while maintaining a reliable seal, preventing electrical and fluid ingress, and enhancing the durability of the weld joint between the retainer and the header body, thereby ensuring the device's operational integrity.
Implementation Method 1
The retainer is coupled to the header body by ultrasonically welding the first welding surface to the second welding surface
Implementation Method 2
when welded, the energy director at least partially forms a joint between the retainer and the header body
Data Source
AI summary
An implantable medical device includes a header body and a septum assembly. The header body includes a first welding surface and a septum bore extending inwardly from an outer surface to an inner cavity. The septum assembly is at least partially disposed within the septum bore of the header assembly and includes a septum configured to allow insertion of a tool through the septum into the inner cavity and to otherwise provide a seal. The septum assembly further includes a retainer within which at least a portion of the septum is retained. The retainer includes a welding feature coupled to the retainer body, the welding feature providing a second welding surface. The retainer is coupled to the header body by welding the first welding surface to the second welding surface.