Optical Force Sensing Assembly for Intravascular Catheters
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Solution Overview
Problem
Current medical optical force sensing assemblies for intravascular devices are costly and complex, limiting their effectiveness and reliability for precise force measurement during procedures like catheter ablation for atrial fibrillation treatment.
Innovation Solution
A medical optical force sensing assembly using a wafer-level camera with a pixel array and an elastic element, such as a helical spring, to measure contact forces applied to the distal end of the device, allowing for 3D sensing and continuous monitoring of forces, which is inexpensive to produce and reduces the risk of fatal side effects during procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a triaxial force sensor with multiple optical fibres is used to measure contact forces, then measurement precision is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent uses a single optical fiber that is routed to reflect multiple copies of light onto different segments of a linear CCD sensor array. This creates multiple measurement channels from a single fiber, replacing the need for multiple separate optical fibers and reducing manufacturing cost while maintaining measurement precision across multiple axes
Solution Approach 2:
A single optical fiber serves multiple functions by providing light for measuring forces in multiple directions (x, y, z axes) through strategic routing and reflection. The same fiber that would traditionally measure only one axis is configured to measure all three spatial dimensions, reducing component count and cost
2Reliability
If force sensing catheters are used to control catheter positioning pressure, then safety is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical triaxial force sensors with an optical measurement system using a single optical fiber and linear CCD array. This substitution simplifies the mechanical structure while enabling three-dimensional force measurement capabilities, reducing device complexity while maintaining safety
Solution Approach 2:
The optical fiber and CCD sensor are integrated into a flexible distal portion of the catheter that can conform to vascular structures. The flexible design allows the sensing assembly to navigate complex anatomical paths without requiring rigid mechanical support structures, reducing overall device complexity
3Object-affected harmful factors
If water irrigation is used to keep endothelial tissue free of lesions, then tissue protection is improved, but manufacturing cost and system complexity increase
Solution Approach 1:
The distal portion of the catheter integrates multiple functions including force sensing, ablation delivery, and water irrigation through a unified flexible structure. The same flexible housing that protects the optical sensing elements also serves as the irrigation channel, eliminating the need for separate irrigation components and reducing system complexity
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 enables precise and continuous measurement of contact forces, improving the safety and efficacy of intravascular procedures by reducing the risk of tissue damage and clotting, while being cost-effective and fault-prone resistant.
Implementation Method 1
optical fibres associated with the housing that measure changes in the intensity of light reflected from the lateral surfaces of the housing resulting from deformation caused by forces applied to a distal extremity of the housing
Implementation Method 2
a sensor tube of an elastic material, contained inside the distal end of the insertion tube and configured to deform in response to forces exerted by the tissue on the distal end
Data Source
Figure 1
Figure 2~2b
Figure 3
AI summary
The present invention concerns an elongated medical device (1 ) suitable for intravascular insertion. Said device comprising a flexible elongated body (2) having a distal portion (3) with a distal end (4) and a proximal portion (5) and an optic force sensing assembly (20) disposed within said flexible elongated body (2) proximate said distal end. The optical force sensing assembly (20) comprises a light source (30), which defines a linear optical light source axis (A), and an optical sensor (40), which faces the light source (30) and which defines a linear optical sensor axis (B) and whereat the optical sensor (40) is arranged in a distance (d0, d1) to the light source along the optical sensor axis (B), a mounting assembly (50) for the optical sensor (40) and the light source (30) which allows for relative movement of the light source (30) against the optical sensor (40) at least in the directions X, Y, Z of the Cartesian coordinate system, wherein direction Z is parallel to the direction of the optical sensor axis (B) at least in an initial state of the optical force sensing assembly (20) and whereby X and Y directions are perpendicular to each other as well as perpendicular to Z direction.