Shape Sensing Fiber Integration in Catheters
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Solution Overview
Problem
Current methods for integrating shape sensing fibers into elongate medical instruments, such as catheters, face challenges with accuracy due to strain changes from mechanical structures, which disrupt the precision of shape algorithms and affect the instrument's performance.
Innovation Solution
The integration and registration of a shape sensing fiber within an elongate instrument involve positioning a portion of the fiber within a lumen and fixing another portion in a known location relative to the instrument, allowing for coordinate system matching to register the fiber accurately, using techniques like sliding or floating the fiber to minimize strain and maintain shape sensing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical fiber is integrated into an elongate instrument such as a catheter, then real time 3-dimensional spatial shape detection is enabled, but large strain changes induced by mechanical structures (such as pinching, twisting) disrupt the accuracy of shape algorithms
Solution Approach 1:
A lumen is introduced as an intermediary structure between the optical fiber and the mechanical environment of the catheter. The lumen provides a protective pathway that isolates the fiber from direct mechanical strain, pinching, and twisting forces, allowing the fiber to maintain its optical properties while the catheter performs its mechanical functions.
Solution Approach 2:
The optical fiber is extracted from the main catheter body and positioned within a separate lumen. This separation allows the fiber to be protected from the mechanical deformations that the catheter undergoes during use, while still enabling shape detection functionality.
2Measurement precision
If components are added to a catheter to enable shape sensing, then shape detection capability is achieved, but the performance of the catheter (such as stiffness, inner and outer diameters) is negatively affected
Solution Approach 1:
The lumen serves multiple functions simultaneously: it provides a protective pathway for the optical fiber, maintains the structural integrity of the catheter, and allows for shape sensing capability. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The optical fiber is nested within the lumen, which itself is integrated into the catheter structure. This nested arrangement allows the shape sensing fiber to be protected and positioned without adding significant external complexity to the catheter design.
3Ease of manufacture
If the fiber is fixed rigidly to the elongate instrument, then coordinate system registration is simplified, but strain changes from mechanical structures disrupt shape algorithm accuracy
Solution Approach 1:
The fiber is allowed to move dynamically within the lumen rather than being rigidly fixed. This dynamic positioning allows the fiber to maintain its shape sensing accuracy by avoiding direct transmission of mechanical strains from the catheter's bending and twisting, while still enabling coordinate system registration through appropriate anchoring at specific locations.
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
This approach enhances the accuracy of shape detection for elongate instruments by reducing strain on the fiber, ensuring precise spatial positioning and shape measurement while maintaining the instrument's functionality and performance.
Implementation Method 1
optical fibers containing optic shape sensors
Implementation Method 2
optical fibers containing optic shape sensors
Data Source
AI summary
Systems and methods for integrating and/or registering a shape sensing fiber in or to various instruments are described herein. Registration fixtures and registration techniques for matching the coordinate system of a fiber to the coordinate system of an elongate instrument or other device are provided. Various systems and methods for integrating a shape sensing fiber into an elongate instrument or other device are also described herein.