Stylet Stiffness Profile Modulation via Strand Variation
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Solution Overview
Problem
Stylets used for guiding catheters require a balance of rigidity and flexibility to navigate vascular pathways effectively, but existing materials often fail to meet these mechanical properties, limiting their suitability for both handling and navigation.
Innovation Solution
A stylet design featuring a core member with varying stiffness characteristics along its length, incorporating A228 carbon steel and a magnetic element with coiled or braided copper wires, allowing for modulated stiffness and enhanced tracking capabilities while maintaining conductive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stylet uses uniform rigid material throughout, then it maintains structural strength and rigidity for handling, but it cannot navigate tortuous vascular pathways effectively
Solution Approach 1:
The stylet is constructed with varying material properties along its length: the proximal portion uses a first material with first mechanical properties optimized for handling and rigidity, while the distal portion uses a second material with second mechanical properties optimized for flexibility and navigation. This local differentiation allows each section to perform its specific function optimally without compromising the other.
Solution Approach 2:
The stylet employs a composite structure combining two different materials with distinct mechanical properties. The proximal portion utilizes a material providing higher rigidity and strength, while the distal portion incorporates a material offering enhanced flexibility and trackability, creating a composite device that balances contradictory requirements throughout its structure.
2Ease of operation
If a stylet uses flexible material to navigate tortuous pathways, then it improves maneuverability, but it loses the rigidity needed for effective manipulation by the clinician
Solution Approach 1:
The stylet is constructed with varying material properties along its length: the proximal portion uses a first material with first mechanical properties optimized for handling and rigidity, while the distal portion uses a second material with second mechanical properties optimized for flexibility and navigation. This local differentiation allows each section to perform its specific function optimally without compromising the other.
Solution Approach 2:
The stylet is divided into distinct segments: a proximal portion for manipulation and a distal portion for navigation. Each segment is engineered with specific material properties tailored to its functional requirements, allowing the proximal segment to provide rigidity for handling while the distal segment provides flexibility for navigating vascular pathways.
3Reliability
If the stylet includes a magnetic element for tracking functionality, then it enables tip tracking and confirmation, but it increases device complexity
Solution Approach 1:
The magnetic element is integrated directly into the distal portion of the stylet wire, merging the tracking functionality with the structural component. This integration eliminates the need for separate tracking devices or additional components, reducing overall system complexity while maintaining reliable tip tracking and confirmation capabilities.
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 stylet achieves improved maneuverability and navigation through tortuous vascular pathways while maintaining effective electrical signal transmission and tracking functionality, leveraging the unique mechanical and conductive properties of the materials used.
Implementation Method 1
The magnet wire can be coiled around the core wire and transmits alternating current pulses, which generates a magnetic field for the system to track.
Data Source
AI summary
A stylet for use in guiding a catheter to a predetermined location within the body of a patient includes a continuous core member for transmitting an electrical signal from a distal section of the stylet to a proximal end. The stylet includes a differing stiffness profile along its length. The differing stiffness characteristics are achieved by varying the number of strands of a wire, the diameter of each individual strand, twisting or braiding the strands, or varying the number of turns per unit length of the twisted strands. The stiffness of the stylet may decrease intermittently or continuously from the proximal end to the distal section. By using multiple strands bundled together, the beneficial conductive and, optionally, magnetic properties can be maximized while at the same time the stiffness characteristics can be modified.