Calibrated Tug Test for Implantable Device Fixation
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Solution Overview
Problem
Operators face challenges in verifying the adequate fixation of implantable medical devices due to variability in the force applied during simple tug tests, as the existing methods do not provide a standardized way to ensure the device is securely fixed to the tissue.
Innovation Solution
A calibrated tug test verification system is introduced, where a core tool is temporarily attached to the device, and a tether with a test segment is used to create a temporary attachment that only releases when a predetermined force greater than or equal to the adequate fixation force is applied, ensuring the device is securely engaged with the tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple tug test is performed by an operator, then the device fixation can be tested, but the force applied varies between operators leading to unreliable verification
Solution Approach 1:
The patent transforms the qualitative tug test into a quantitative measurement by introducing a force sensor that measures the exact force required to displace the device. This changes the parameter from subjective operator perception to objective force measurement, eliminating operator variability while maintaining ease of operation.
Solution Approach 2:
The patent replaces the purely mechanical tug test with a hybrid system that incorporates electronic sensing and digital processing. The force sensor, processor, and display system substitute for manual operator judgment, providing reliable and repeatable fixation verification without compromising operational simplicity.
2Manufacturing precision
If no standardized force is applied during tug test, then the procedure remains simple, but adequate fixation cannot be reliably ensured
Solution Approach 1:
The patent introduces electronic force sensing and digital processing to replace manual force estimation. The force sensor, processor, and display system provide precise measurement and communication of fixation force, ensuring manufacturing precision while managing device complexity through integrated electronic components.
Solution Approach 2:
The patent creates a digital representation of the physical fixation force through the force sensor and processor. This digital copy of the mechanical force allows for precise measurement, comparison against thresholds, and clear communication to the operator, achieving precision without excessive complexity.
3Reliability
If a calibrated tug test system is implemented, then reliable fixation verification is achieved, but the device complexity increases
Solution Approach 1:
The force sensor and processing system serve multiple functions: measuring fixation force, comparing against thresholds, generating visual feedback, and potentially guiding the implantation process. This multi-functionality justifies the added complexity by providing comprehensive verification and control capabilities within a single integrated system.
Solution Approach 2:
The patent implements a feedback loop where the force sensor continuously monitors fixation force, the processor compares it against predetermined thresholds, and the display provides real-time visual feedback to the operator. This feedback mechanism enhances reliability by providing continuous verification while managing complexity through automated processing and clear information presentation.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A
AI summary
A tool of an interventional medical systems system includes a core configured to be temporarily attached to the implantable medical device, as the tool deploys the device to expose a fixation member of the device for engagement with tissue at a target implant site; the core is then employed to verify adequate fixation of the deployed device via a tug test. An operator determines that the device is adequately fixed by the engaged fixation member, if a tug force that is applied to the core modifies the temporary attachment between the core and the device, to allow release of the device from the temporary attachment. A tether, which is fixedly attached to the core, may be employed to create the temporary attachment between the core and the device, or the temporary attachment may be created by a snap fit formed between the core and the attachment structure of the device.