Active Fixation Cardiac Lead Integral Protrusion Design
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Solution Overview
Problem
Existing active fixation cardiac electrode leads face issues such as tissue being caught and torn during repositioning or explantation, limited helix diameter due to housing wall thickness, risk of pin loss, and material instability, which affects fixation strength and safety.
Innovation Solution
The solution involves replacing the traditional pin with an integral protrusion formed through a cold forming process, creating a single, strong housing component with a thin wall and embossed protrusion that follows the helix thread, eliminating undercuts and reducing friction, and providing a larger helix diameter for enhanced fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pin is used to mediate axial movement of the fixation helix, then the helix can be extended and retracted, but tissue can be caught and torn during repositioning or explantation
Solution Approach 1:
The pin and housing are merged into a single integral component through cold forming. The protrusion is formed directly from the housing material, eliminating the separate pin component. This integration ensures that tissue cannot be caught between separate parts, while still providing the necessary mechanical function of mediating axial movement of the fixation helix during extension and retraction operations.
Solution Approach 2:
The housing is formed with a thin wall through cold forming, allowing the protrusion to be created without requiring thick walls. This thin-walled design eliminates undercuts that could trap tissue, while the cold forming process creates a smooth, continuous surface that prevents tissue catching during lead manipulation.
2Ease of operation
If a pin is mounted in a metal housing, then axial movement can be mediated, but the wall thickness increases limiting the helix diameter
Solution Approach 1:
The pin and housing are merged into a single integral component through cold forming. The protrusion is formed directly from the housing material, eliminating the need for a separate mounted pin. This integration allows the housing wall to be made thinner while still providing the necessary mechanical function, thereby increasing the internal volume available for the fixation helix and allowing for a larger helix diameter.
Solution Approach 2:
The cold forming process changes the physical parameters of the housing material, allowing it to be shaped into an integral structure with thin walls and precise protrusion geometry. This process enables the housing to maintain structural integrity and mechanical function with reduced wall thickness, maximizing the space available for the fixation helix.
3Stability of the object's composition
If a pin is welded to a metal housing, then the pin can be fixed, but the wall thickness must be large for mounting
Solution Approach 1:
The pin and housing are merged into a single integral component through cold forming. The protrusion is formed directly from the housing material in a single manufacturing step, eliminating the need for separate mounting operations like welding. This integration provides stable fixation of the protrusion to the housing while eliminating the need for thick walls required for separate component mounting.
Solution Approach 2:
The separate pin component and its mounting process (welding, additional parts) are extracted from the design. The function of the pin is retained through the integral protrusion formed by cold forming, which provides equivalent or superior fixation stability without requiring additional wall thickness for mounting hardware.
4Ease of manufacture
If plastic housing is used, then material instability occurs requiring larger wall thickness
Solution Approach 1:
The cold forming process changes the physical parameters of the housing material (whether metal or plastic), allowing it to be shaped into an integral structure with thin walls. This process provides sufficient structural stability and dimensional accuracy without requiring thick walls, thereby maximizing the internal volume for the fixation helix while maintaining manufacturing feasibility.
Solution Approach 2:
The housing and protrusion are merged into a single integral component through cold forming. This integration eliminates the need for thick walls that would be required to separately mount a pin in plastic housing, as the protrusion is formed directly from the housing material with precise geometry and structural integrity.
5Ease of operation
If a pin is used as an additional component, then axial movement can be mediated, but there is risk of pin loss causing embolism
Solution Approach 1:
The pin and housing are merged into a single integral component through cold forming. The protrusion is formed directly from the housing material, eliminating the separate pin component that could become loose or detached. This integration ensures that the structure mediating axial movement of the fixation helix cannot be lost, eliminating the risk of embolism from detached components while maintaining the necessary mechanical function.
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 design minimizes tissue damage during lead repositioning, allows for a stronger fixation, prevents pin loss, and reduces deformation and friction, while being economically viable and safer for the patient.
Implementation Method 1
replacing the prior art pin by an integral protrusion of the housing formed into the housing by a cold forming process of the housing
Data Source
AI summary
An active fixation cardiac electrode lead having a fixation helix movably placed in a housing at the electrode lead's distal end so as to be extended out of the housing's distal end and retraced into an inner space enclosed by the housing. The housing has a wall and a protrusion formed in the wall that protrudes into the inner space into interspaces between windings of the fixation helix. The protrusion causes an axial movement of the helix when the helix is rotated around its longitudinal axis. The protrusion is an integral part of the housing's wall which is bent or embossed to form the protrusion.