Optical Force Sensing Catheter Tip Design

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Solution Overview

Problem

Existing catheter-based diagnostic and treatment systems lack the ability to accurately sense forces applied to the distal tip of a catheter, leading to inaccurate mapping and potential tissue damage due to unstable contact with the organ wall, especially during procedures like cardiac ablation.

Innovation Solution

A force sensing system utilizing a deformable body near the distal tip of a medical catheter, coupled with fiber-optic sensors and processor circuitry, which detects deformation to determine the force applied, and a manifold that transmits and absorbs forces to prevent plastic deformation and improve measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a rigid catheter tip is used to maintain stable contact with the organ wall, then contact stability is improved, but the ability to sense applied force is worsened due to lack of deformation

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

Solution Approach 1:

The catheter tip is designed with spatially varying properties: the distal portion is made compliant and deformable to enable force sensing through deformation, while the proximal portion remains rigid for structural stability and catheter control. This local differentiation allows the tip to simultaneously achieve contact stability and force measurement capability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

A deformable body acts as an intermediary element between the rigid catheter shaft and the organ wall. This intermediate component transmits contact forces to fiber-optic sensors while maintaining compliant contact with the tissue, enabling force sensing without compromising contact stability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If excessive contact force is applied to ensure effective treatment, then treatment efficacy is improved, but tissue damage risk is worsened

Engineering Contradiction:
Improvetreatment efficacyVSAvoidtissue damage risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system incorporates real-time force sensing that provides feedback to the operator about the actual contact force applied to the tissue. This feedback enables the operator to adjust the contact force to an optimal level that ensures effective treatment while avoiding excessive force that could cause tissue damage or puncture.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The catheter tip is designed with dynamic compliance, allowing it to adapt its contact force based on tissue conditions. The deformable body can flex and deform in response to tissue variations, enabling the system to maintain appropriate contact force ranges dynamically throughout the procedure.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If minimal contact force is applied to avoid tissue damage, then tissue safety is improved, but treatment efficacy is worsened due to unstable contact

Engineering Contradiction:
Improvetissue safetyVSAvoidtreatment efficacy
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The distal portion of the catheter tip is designed with localized compliance and deformability, allowing it to conform to tissue surfaces and maintain stable contact even with minimal applied force. This local quality enhancement ensures that treatment efficacy is maintained while minimizing the risk of tissue damage from excessive force.

Inventive Principle:
Principle #3Local quality

4Measurement precision

If a deformable body is added to enable force sensing, then force measurement capability is improved, but device complexity is worsened

Engineering Contradiction:
Improveforce measurement capabilityVSAvoidcatheter structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical force sensing mechanisms with a fiber-optic-based sensing system. The deformable body is instrumented with fiber-optic sensors that detect deformation optically, eliminating the need for complex mechanical transducers, strain gauges, or electronic sensors, thereby reducing overall device complexity.

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

Solution Approach 2:

The deformable body serves multiple functions simultaneously: it provides compliant contact with tissue, transmits contact forces to sensors, and acts as a structural element of the catheter tip. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.

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

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

Enables precise force measurement and feedback to clinicians, ensuring consistent and controlled tissue contact, reducing the risk of tissue damage and improving the efficacy of ablation therapies by maintaining uniform lesion lines.

Implementation Method 1

The fiber-optic force sensor detects various components of the deformation

Methodology Applied
Scientific EffectOptical deformation detection:

Data Source

PatentEP3624717B1Optical force sensing catheter system
Publication Date: 2022.02.09 ST JUDE MEDICAL INT HLDG SARL
  • EP3624717B1 patent drawingFigure 1
  • EP3624717B1 patent drawingFigure 1A~1C
  • EP3624717B1 patent drawingFigure 2A

AI summary

Aspects of the present disclosure are directed toward systems and methods for detecting force applied to a distal tip of a medical catheter. In some embodiments, a medical catheter with a deformable body near a distal tip of the catheter deforms in response to a force applied at the distal tip, and a force sensor detects various components of the deformation. Processor circuitry may then, based on the detected components of the deformation, determine a force applied to the distal tip of the catheter.