Guidewire Stiff-Middle Structure for Catheter Needle Tip Blunting
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Solution Overview
Problem
The insertion of needles through catheter lumens can cause punctures in the catheter walls, rendering them unfit for use, due to the flexibility and sharpness of the needles.
Innovation Solution
A guidewire with a flexible distal section, a stiff middle section, and a flexible proximal section, where the middle section is designed to blunt the needle tip by constraining the catheter away from the sharp point, using a cannula or material to define a longitudinal sliding fit, ensuring the needle tip does not pierce the catheter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sharp needle is inserted through the lumen of a flexible catheter, then the needle provides a sharp tip for effective insertion, but the needle tip may pierce the catheter wall rendering it unfit for use
Solution Approach 1:
A blunting element is introduced as an intermediary component between the sharp needle tip and the catheter wall. This blunting element contacts the catheter wall first during insertion, preventing the sharp needle tip from directly piercing the catheter while still allowing effective insertion through the lumen.
Solution Approach 2:
The catheter assembly is segmented into distinct functional zones: a flexible distal section for navigation, a stiff middle section containing the blunting element to protect the catheter wall, and a proximal section for manipulation. This segmentation allows different parts to perform different functions simultaneously.
2Ease of operation
If the catheter tubular portions are made flexible to facilitate insertion, then the catheter can be easily positioned, but the flexible nature increases the risk of needle tip puncture
Solution Approach 1:
The blunting element serves as a protective intermediary that contacts the flexible catheter wall during needle insertion, preventing the sharp needle tip from piercing the wall while the flexible catheter maintains its ease of positioning characteristics.
Solution Approach 2:
The blunting element is positioned beforehand in the catheter lumen to cushion or absorb the potential puncturing action of the needle tip before it can contact and damage the catheter wall, thereby preventing harm in advance.
3Reliability
If a stiff middle section is added to the guidewire to blunt the needle tip, then the catheter wall is protected from puncture, but the device complexity increases
Solution Approach 1:
The guidewire is divided into three distinct sections with different properties: a flexible distal section for navigation, a stiff middle section containing the blunting element for protection, and a flexible proximal section for manipulation. This segmentation provides functional differentiation while maintaining manageable complexity.
Solution Approach 2:
Different sections of the guidewire have different mechanical properties localized to their specific functions: the middle section is stiff to protect the catheter wall, while the distal and proximal sections remain flexible for navigation and manipulation, respectively.
Data Source
AI summary
Guidewires include a distal section, a proximal section and a middle section disposed between the distal section and the proximal section, wherein the middle section has a flexural stiffness that is greater than a flexural stiffness of both of the distal section and the proximal section. The distal section is configured for insertion into a vasculature of a patient. A diameter of the middle section may be greater than a diameter of the distal section. The guidewires may include a tapered distal transition portion disposed between the distal section and the middle section and a solid core wire extending a length of the guidewires, the solid core wire including a first diameter extending along the distal section, a second diameter extending along the proximal section, and a third diameter extending along the middle section, wherein the third diameter is greater than the first diameter and the second diameter.