Implantable Sensor Fixation With Asymmetric Multi-Loop Strain Relief
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Solution Overview
Problem
Existing implantable medical devices face challenges in maintaining stable positioning and minimizing mechanical strain on sensing elements within the body, particularly in vascular environments, which affects their operational accuracy and durability.
Innovation Solution
The use of a fixation assembly with asymmetric fixation members, each comprising multiple loops of varying pitches, allows the device to be compressed for delivery and expands for secure positioning within the vessel, minimizing strain on the sensing element while ensuring stable placement and unobstructed blood flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixation assembly with rigid structure is used to secure the implantable sensor, then positioning stability is improved, but mechanical strain on the sensing element increases
Solution Approach 1:
The fixation assembly is divided into multiple fixation members (first and second fixation members) that can independently engage with the vessel wall at different locations. Each fixation member has a structure with multiple loops that can be compressed for delivery and expand for fixation, allowing distributed mechanical support without concentrating strain on a single rigid structure.
Solution Approach 2:
The fixation members are designed to be compressible during delivery and expandable at the implant site. The loops in each fixation member can dynamically adjust their configuration - compressed to a narrow profile for delivery through the delivery catheter, then expanded to provide secure anchoring in the vessel wall, adapting the fixation mechanism to different operational requirements.
2Ease of operation
If the fixation assembly is made compressible for delivery, then ease of delivery through catheter is improved, but fixation strength at implant site may be compromised
Solution Approach 1:
The fixation members utilize superelastic material properties to change their dimensional parameters - the loops are compressed to reduce the pitch and width dimensions for delivery through the catheter, then expand to their full dimensions at the implant site. This parameter transformation allows the same structure to serve both delivery and fixation requirements effectively.
Solution Approach 2:
The fixation members are formed from superelastic material that combines flexibility with high strength characteristics. This material allows the structure to be compressed for delivery while maintaining the capability to expand and provide strong fixation. The superelastic property enables reversible deformation without permanent damage, ensuring both deliverability and fixation strength.
3Object-affected harmful factors
If multiple loops of varying pitches are used in fixation members, then strain relief is improved, but device complexity increases
Solution Approach 1:
Different loops within each fixation member have different pitch characteristics - some loops have larger pitch while others have smaller pitch. This local variation in quality allows specific loops to engage with the vessel wall at different depths and locations, providing distributed strain relief across the fixation member while maintaining overall structural coherence.
Solution Approach 2:
The fixation members feature asymmetric loop configurations where the loops are not uniformly spaced or sized. The first loop has a different maximum pitch than the second loop, creating an asymmetric structure that better conforms to the curved geometry of blood vessels and provides more effective strain distribution while maintaining a manageable overall structure.
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 configuration ensures durable and accurate sensing by reducing mechanical loads on the sensing element, maintaining positional integrity, and allowing unobstructed blood flow, thereby enhancing the longevity and performance of implantable medical devices.
Implementation Method 1
The fixation assembly may be formed from a superelastic material and the multi-loop structure is compressible to a delivery configuration that has a narrower profile in relation to a deployment configuration
Data Source
AI summary
An implantable medical device, such as a sensor for monitoring a selected internally detectable physiological parameter of a patient, is attached to a fixation assembly that is deployable within the patient to position and orient the sensor to enable it to perform its function. The fixation assembly is formed having at least one flexible asymmetric connector where each fixation member includes a plurality of loops, wherein a first loop of the plurality of loops has a maximum pitch that is different from a maximum pitch of a second loop of the plurality of loops. The attachment of the housing and the fixation assembly includes providing a tubular member that is welded to the housing and crimped over a section of the fixation assembly.