Calibrated Tether Test Segment for Implant Fixation Verification

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

There is a need for a calibrated tug test verification method to ensure adequate fixation of implantable medical devices at a target implant site, as the current simple tug test does not provide consistent force application, leading to variability in operator-assessed fixation quality.

Innovation Solution

A tether subassembly with a test segment is integrated into the delivery tool, where a predetermined force is required to pull the test segment through an aperture, ensuring that the device is adequately fixed to the tissue, with the force corresponding to a minimum adequate fixation force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a simple tug test is used to verify fixation, then the operation is simple and quick, but the measurement precision and reliability of fixation verification are insufficient due to lack of calibrated force application

Engineering Contradiction:
Improvesimplicity of tug testVSAvoidfixation verification accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

A force transmission element (tether) is introduced as an intermediary between the operator's pulling action and the fixation verification. This tether transmits the applied force through the device to the fixation member, enabling indirect but measurable force application that bridges the gap between simple operation and precise measurement

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameter of force measurement from uncalibrated operator perception to calibrated force verification. By establishing a predetermined force threshold that corresponds to minimum adequate fixation force, the system transforms the tug test from a qualitative assessment to a quantitative measurement with defined parameters

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If uncalibrated tug force is applied by operators, then the operation remains simple, but the reliability and consistency of fixation verification vary between operators

Engineering Contradiction:
Improveoperator independenceVSAvoidconsistency of fixation verification
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system establishes a predetermined force parameter that serves as a standardized threshold for adequate fixation. This calibrated force level ensures that all operators verify fixation against the same objective criterion, eliminating variability between operators while maintaining procedural simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system provides feedback through the force transmission mechanism, allowing operators to sense when the predetermined force threshold has been reached. This tactile feedback loop enables consistent verification without requiring complex measurement instruments, maintaining ease of operation while improving reliability

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3125995B1Interventional medical systems, tools, and subassemblies
Publication Date: 2018.05.16 MEDTRONIC INC
  • EP3125995B1 patent drawingFigure 1A~1B
  • EP3125995B1 patent drawingFigure 2A~2B
  • EP3125995B1 patent drawingFigure 3A~3B

AI summary

A tether subassembly, which may be employed by a tool that deploys an implantable medical device, includes a test segment for verification of adequate fixation of the device at an implant site. When the device is located in proximity to a distal opening of the tube, a tether first length extends through an attachment structure of the device and within an elongate tube of the tool, a tether second length extends alongside the tether first length within the tube, and the test segment is located in proximity to the distal opening. The test segment is configured so that only a tug force, applied to the tether first length, and greater than or equal to a predetermined force, can pull the test segment through an aperture, either of the delivery tool or of the device. The predetermined force corresponds to a minimum adequate fixation force for the device.