Frictional Lumen Design for Optical Shape Sensing
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Solution Overview
Problem
Optical shape sensing fibers integrated into medical devices face challenges such as limited space, susceptibility to external forces like tension, twist, and vibration, which degrade performance and accuracy in dynamic environments like vascular navigation.
Innovation Solution
A flexible lumen design with frictional contact between longitudinal members to maintain dimensions and house a shape sensing optical fiber, featuring a textured, braided, or non-uniform inner surface to reduce stick-slip behavior and ovalization, and twisted filars for vibration dampening, allowing the fiber to slide freely and decouple torque from twisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the optical fiber is integrated into a medical device with small cross-sectional footprint, then the device can be used in vascular navigation, but the shape sensing performance degrades due to susceptibility to tension, twist, vibration and pinching
Solution Approach 1:
The lumen is divided into multiple longitudinal members (e.g., 3-7 individual walls) that are held together to form a complete circular structure. Each longitudinal member independently contacts and supports the optical fiber, distributing mechanical stresses and preventing pinching while maintaining structural integrity for device flexibility and navigability
Solution Approach 2:
The longitudinal members act as intermediary protective elements between the external dynamic environment (tension, twist, vibration) and the optical fiber. These members absorb and distribute mechanical stresses, preventing direct transmission of harmful forces to the fiber while maintaining the lumen's structural stability
2Stability of the object's composition
If the longitudinal members have frictional contact to maintain lumen dimensions, then structural stability is improved, but stick-slip behavior and rotational friction increase
Solution Approach 1:
The inner surface of the longitudinal members features localized texturing or non-uniformities at specific contact points. This creates controlled friction zones that maintain lumen dimensional stability while allowing smooth rotational movement of the fiber in other areas, reducing overall stick-slip behavior
Solution Approach 2:
The longitudinal members are designed to dynamically adjust their contact pressure with the fiber based on external forces. During rotation or vibration, the contact points shift and pressure redistributes, preventing sustained stick-slip interactions while maintaining structural stability under static or slowly varying loads
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 enhances shape sensing performance by minimizing external influences, maintaining a smooth lumen, reducing stick-slip and rotational friction, and effectively dampening vibrations, thereby improving accuracy and stability of shape reconstruction.
Implementation Method 1
The longitudinal members have frictional contact therebetween and are configured to engage neighboring longitudinal members during bending, twisting or external pressure to maintain dimensions of the lumen
Implementation Method 2
featuring a textured, braided, or non-uniform inner surface to reduce stick-slip behavior
Implementation Method 3
twisted filars for vibration dampening, allowing the fiber to slide freely and decouple torque from twisting
Data Source
AI summary
A shape sensing enabled instrument includes a flexible longitudinal body (300) including a plurality of longitudinal members (310) held together to form a lumen (205). The longitudinal members have frictional contact therebetween and are configured to engage neighboring longitudinal members during bending, twisting or external pressure to maintain dimensions of the lumen. A shape sensing optical fiber (302) is disposed within the lumen.