Optical Fiber Lumen Design for Torque Decoupling in Shape Sensing
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Solution Overview
Problem
Optical shape sensing fibers face challenges in medical devices due to limited cross-sectional area, susceptibility to external environment changes, and torque-induced twist, which affect performance and accuracy in navigation and localization during surgical interventions.
Innovation Solution
A flexible medical instrument design with a hollow lumen that encapsulates the optical fiber, allowing rotation and translation, and is configured to dampen vibrations and decouple torque from fiber twist, using existing structural elements like guide wires or pull wires as the lumen to optimize space and reduce friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical fiber is integrated directly into the medical device without a protective lumen, then the device complexity is reduced, but the fiber is susceptible to external environment changes, torque-induced twist, and friction which deteriorate sensing accuracy
Solution Approach 1:
The patent implements a nested structure where the optical fiber is placed within an optical fiber lumen, which is in turn positioned inside a hollow mechanical member (guide wire or pull wire). This multi-layer nesting provides progressive protection: the optical fiber lumen protects the fiber from direct environmental exposure, while the mechanical member provides additional structural protection and torque isolation. The nested arrangement resolves the contradiction by ensuring measurement precision through layered protection while maintaining reasonable device complexity by utilizing existing structural elements.
Solution Approach 2:
The patent introduces an intermediary optical fiber lumen between the optical fiber and the external environment. This intermediary structure serves as a protective barrier that isolates the fiber from harmful external factors including torque, friction, and environmental changes. The lumen acts as a mediator that allows the fiber to maintain its sensing function while being protected from direct interaction with adverse conditions, thereby improving measurement precision without requiring direct integration of the fiber into the device structure.
2Area of moving object
If the cross-sectional area of the medical device is reduced to improve deliverability, then the device can be delivered through smaller vessels, but the space available for the optical fiber and its protective structures is limited
Solution Approach 1:
The patent applies multi-functionality by utilizing the hollow mechanical member (guide wire or pull wire) to serve dual purposes: it provides structural support and torque transmission for the medical device while simultaneously housing the optical fiber lumen. This universal use of existing structural elements eliminates the need for additional dedicated space for fiber protection, allowing the device to maintain a small cross-sectional area for deliverability while still providing adequate protection and space for the optical fiber to ensure measurement precision.
Solution Approach 2:
The patent merges the protective lumen structure with the existing mechanical member (guide wire or pull wire) by positioning the optical fiber lumen inside the hollow interior of these components. This merging combines the protective function with the structural function, allowing the device to maintain a compact cross-sectional area. The optical fiber and its protective lumen are integrated within the existing mechanical architecture, optimizing space utilization and ensuring measurement precision without increasing the overall device size.
3Reliability
If the optical fiber is constrained within a rigid lumen to protect it, then the fiber is protected from damage, but the fiber cannot rotate or translate freely which affects shape sensing performance
Solution Approach 1:
The patent implements dynamics by designing the optical fiber lumen as a movable, flexible structure rather than a rigid constraint. The lumen is positioned within the hollow mechanical member in a manner that allows it to move, rotate, and translate freely along with the optical fiber. This dynamic arrangement ensures the fiber remains protected within the lumen while maintaining the freedom of movement necessary for accurate shape sensing, resolving the contradiction between protection and performance.
Solution Approach 2:
The patent employs a flexible lumen structure that can deform and move with the optical fiber rather than constraining it rigidly. This flexible shell approach allows the lumen to provide protective enclosure while accommodating the fiber's rotational and translational movements. The flexible nature of the lumen ensures both fiber protection and freedom of movement, maintaining measurement precision while preventing damage to the optical fiber.
Data Source
AI summary
A shape sensing enabled instrument includes a flexible guide wire or support rod including an outer surface which encapsulates interior features. The interior features include an optical fiber lumen (105) configured to receive one or more optical fibers for optical shape sensing, and a guide wire support rod or the support rod forming a hollow extending longitudinally along the instrument. The guide wire support rod or the support rod is configured to receive the optical fiber lumen therein to permit rotation and translation of an optical fiber and to protect the optical fiber.