Break-Away Tethering Feature for Implantable Medical Devices
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Solution Overview
Problem
Existing implantable cardiac pacemakers face mechanical complications and MRI compatibility issues due to elongate lead wires, prompting the development of compact devices that require improved tethering features for easier deployment and removal from delivery catheters.
Innovation Solution
A tethering feature with an elongate break-away member and base, where the break-away member's ends are wrapped around supports and can deform to separate from the base when a pull force is applied, assisted by a back-up force from the catheter shaft, allowing for efficient tethering and untethering of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compact implantable medical device is deployed from a delivery catheter, then the device can be positioned at the implant site, but the device becomes difficult to remove or reposition if fixation is too strong
Solution Approach 1:
The tethering feature transitions from a fixed, strong fixation state to a releasable state through the break-away mechanism. The break-away member remains intact during normal fixation but can be separated when removal force is applied, allowing the device to transition between secured and removable states dynamically.
Solution Approach 2:
The tethering feature is divided into separable components: the break-away member that can be detached from the base. This segmentation allows the tethering system to provide strong fixation when needed while enabling easy separation for device removal or repositioning by pulling the tether.
2Ease of operation
If the tethering feature uses a break-away member wrapped around supports, then the device can be easily untethered, but the structure becomes more complex
Solution Approach 1:
The break-away member is designed to automatically separate from the base when sufficient pull force is applied to the tether. The structure itself provides the release mechanism through its geometry and material properties, eliminating the need for additional active release components or complex control systems.
3Ease of manufacture
If the break-away member is made from a single piece of metal, then manufacturing is simplified, but the ability to deform and separate from the base is reduced
Solution Approach 1:
The break-away member is designed with specific geometric parameters including deformable portions with reduced cross-sectional areas or modified material properties in specific zones. These parameter changes create predetermined weak points that facilitate controlled deformation and separation while maintaining overall structural integrity during normal operation.
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
Enhances the ease of tethering and untethering of compact implantable medical devices, ensuring secure fixation and easy repositioning without mechanical complications, while maintaining device stability and MRI compatibility.
Implementation Method 1
the break-away member's ends are wrapped around supports and can deform to separate from the base when a pull force is applied
Data Source
AI summary
A tethering feature includes an elongate break-away member and a base, and forms a proximal end of an implantable medical device housing. A tether attachment zone of the break-away member extends between break-away member ends, and the base includes a pair of supports, wherein each end of the break-away member is wrapped around a corresponding support. A delivery catheter tether may be attached to the device tethering feature by passing a looped portion of the tether around the tether attachment zone. The device may be untethered from the catheter by applying a pull force through the attached tether, while a distal end of a shaft of the catheter, which abuts the device proximal end, provides a back-up force, the pull force unwrapping each end of break-away member from the corresponding base support.