Tubular Moisture Barrier for Medical Force Sensor

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Solution Overview

Problem

Existing catheter-based diagnostic and treatment systems for organs or vessels lack precise measurement of contact forces with the vessel or organ wall, leading to imprecise treatment and potential tissue damage due to inadequate force sensing capabilities.

Innovation Solution

A medical device with a force sensor and a tubular moisture barrier that extends along the catheter shaft, featuring a coaxially bonded inner and outer layer to prevent moisture interference with the force sensor, ensuring accurate force measurements by maintaining the integrity of the optical interferograms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the force sensor is exposed to the external environment, then the device structure is simpler, but moisture interference degrades measurement precision

Engineering Contradiction:
Improvedevice structureVSAvoidforce measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

A moisture barrier layer is introduced as an intermediary component between the force sensor and the external environment. This barrier layer prevents moisture from reaching the optical components of the force sensor, thereby maintaining measurement precision without requiring complex sealing mechanisms or environmental control systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A flexible moisture barrier film is applied over the force sensor. This thin film structure provides moisture protection while maintaining the sensor's ability to detect force through the film, thus preserving measurement precision without significantly increasing device complexity

Inventive Principle:
Principle #30Flexible shells and thin films

2Stability of the object's composition

If expandable baskets or hooks are used to stabilize the catheter, then the catheter position is stabilized, but the system cannot sense the load applied by tissue wall movement

Engineering Contradiction:
Improvecatheter position stabilityVSAvoidforce sensing capability
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The force sensor is integrated directly into the distal extremity of the catheter, merging the stabilization function (through contact with tissue) and the force sensing function into a single component. This allows the catheter to both stabilize its position and simultaneously sense the load applied by tissue wall movement

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The distal extremity of the catheter is designed to perform multiple functions: it provides mechanical stabilization through contact with the tissue wall and simultaneously acts as a force sensor to detect tissue movement and applied load, eliminating the need for separate stabilization and sensing mechanisms

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If manual feedback or impedance measurements are used for positioning, then the mapping can be completed, but the process is time-consuming and cannot detect contact forces

Engineering Contradiction:
Improvemapping efficiencyVSAvoidcontact force detection
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

Manual feedback mechanisms are replaced with an automated optical force sensor that directly measures contact forces. This substitution enables real-time detection of contact forces between the catheter and tissue wall, significantly improving mapping efficiency and providing precise force measurement data that was previously unavailable

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution provides precise force sensing capabilities, minimizing tissue damage and ensuring effective treatment by preventing moisture interference, thus enhancing the accuracy and reliability of catheter-based procedures.

Implementation Method 1

A tubular moisture barrier extends along the shaft longitudinal axis between the shaft distal end and the tip, and wherein the force sensor is disposed within the barrier lumen

Methodology Applied
Scientific EffectPhysical barrier (moisture barrier): Physical Containment

Implementation Method 2

maintaining the integrity of the optical interferograms

Methodology Applied
Scientific EffectOptical interferometry: Interference

Data Source

PatentEP3565458B1Elastomeric moisture barrier for force sensor
Publication Date: 2022.11.02 ST JUDE MEDICAL INT HLDG SARL
  • EP3565458B1 patent drawingFigure 1
  • EP3565458B1 patent drawingFigure 2
  • EP3565458B1 patent drawingFigure 3

AI summary

A medical device can include an elongate shaft extending along a shaft longitudinal axis, which can include a shaft proximal end and a shaft distal end. A force sensor can be disposed on the shaft distal end and can include a sensor proximal end and a sensor distal end. A tip can be disposed on the sensor distal end. A tubular moisture barrier can define a barrier lumen, wherein the tubular moisture barrier extends along the shaft longitudinal axis between the shaft distal end and the tip, and wherein the force sensor is disposed within the barrier lumen.