Formable Stylet for Disposable Catheter Systems
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Solution Overview
Problem
The high cost and complexity of reusing catheter stylets, particularly those made of expensive materials like Nitinol, due to their difficulty in machining and the need for sterilization, result in significant disposal costs, while existing catheters are often not designed for cost-effective single-use solutions.
Innovation Solution
A formable stylet made from low-cost, biocompatible materials like stainless steel or cobalt-chromium-nickel alloys with a distal portion of reduced stiffness, allowing manual shaping and retention of configuration, integrated with a low-cost catheter assembly for disposable use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed curve stylet is used, then the catheter can maintain a predetermined shape for steering, but the material cost and manufacturing complexity increase significantly
Solution Approach 1:
The stylet transitions from a fixed static curve to a dynamic formable structure. The distal portion is made with reduced stiffness, allowing it to be manually shaped by the clinician into the desired configuration before insertion, while the proximal portion maintains sufficient rigidity for steering. This dynamic adaptability eliminates the need for expensive fixed curve machining.
Solution Approach 2:
The stylet body is divided into regions with different stiffness characteristics. The proximal portion maintains full stiffness for steering control, while the distal portion has reduced stiffness to enable manual shaping. This local differentiation allows the stylet to achieve both formability and steering capability without requiring expensive fixed curve manufacturing throughout the entire structure.
2Stability of the object's composition
If expensive materials like Nitinol are used for the stylet, then the stylet can retain its shape and provide sufficient stiffness, but the disposal cost increases significantly
Solution Approach 1:
The stylet is designed as a disposable component made from cost-effective materials such as stainless steel or cobalt-chromium-nickel alloys. The reduced stiffness of the distal portion is achieved through geometric shaping rather than expensive material usage, enabling single-use disposal without significant cost impact. This eliminates the need for expensive Nitinol while maintaining adequate performance for the procedure.
Solution Approach 2:
Instead of changing the material composition to achieve shape retention, the invention changes the geometric parameters of the distal portion to reduce stiffness. By shaping the distal portion (e.g., flattening, reducing cross-sectional area), the stylet achieves formability and shape retention through geometry rather than expensive alloy materials, significantly reducing disposal costs.
3Ease of operation
If the distal portion is made with reduced stiffness, then the stylet can be manually shaped into desired configurations, but the overall stiffness for steering may be compromised
Solution Approach 1:
The stylet is segmented into two distinct portions with different stiffness characteristics: a proximal portion with full stiffness for steering control and a distal portion with reduced stiffness for manual shaping. This segmentation allows each portion to optimize its properties for its specific function, ensuring that steering capability is not compromised while enabling formability at the distal end.
Solution Approach 2:
Different portions of the stylet have different stiffness properties tailored to their specific functions. The proximal portion maintains high stiffness for steering, while the distal portion has reduced stiffness for shaping. This local quality differentiation resolves the contradiction by ensuring that steering stiffness is maintained where needed while formability is enabled where required.
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 formable stylet enables cost-effective, single-use catheter systems with reduced material costs and simplified disposal, while maintaining the necessary stiffness for steering and retaining desired shapes during use.
Implementation Method 1
the distal portion being able to be manipulated into a desired configuration... the distal portion may be machined into a flattened shape... the distal portion may be worked into the flattened shape by rolling
Implementation Method 2
By 'flexible' is meant that the elongate body member is able to be bent into a desired shape but still has sufficient rigidity or stiffness to enable a catheter in which the stylet is received to be steered
Data Source
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AI summary
A formable stylet 10 includes an elongate body member 12 of a flexible material, the body member having a proximal end 14 and a distal end 16. The body member 12 has a distal portion 18 of reduced stiffness in comparison with the remainder of the body member 12, the distal portion 18 being able to be manipulated into a desired configuration.