Flexible Needle Jacketing With Decoupled Regions
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Solution Overview
Problem
Existing flexible medical needle assemblies face challenges in maintaining durability and flexibility while minimizing diameter, as conventional jacketing materials can restrict movement and lead to jacket rupture under bending stresses.
Innovation Solution
A medical flexible needle assembly with a selectively decoupled jacketing system, featuring coupled and decoupled regions that allow for optimal flexibility and durability, where decoupled regions are strategically placed to reduce strain and enhance angulation, using materials like Pebax, PTFE, and adhesives to control adhesion and mechanical joining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional jacketing materials are used to maintain vacuum seal and durability, then reliability is improved, but flexibility deteriorates and jacket rupture occurs under bending stresses
Solution Approach 1:
The jacket is divided into multiple segments that can move independently relative to each other. The jacket includes a first portion and a second portion that are separable, allowing the needle assembly to flex and bend without causing the entire jacket to rupture. This segmentation enables the vacuum seal to be maintained in the rigid portions while allowing flexibility in the segmented regions.
Solution Approach 2:
The jacket transitions from a static, rigid structure to a dynamic, flexible structure. The jacket portions can move, separate, and reconfigure during needle insertion and manipulation. This dynamic behavior allows the jacket to adapt to bending stresses and maintain both vacuum seal integrity and flexibility throughout the procedure.
2Ease of operation
If the needle assembly diameter is reduced for better anatomical navigation, then ease of operation is improved, but structural stability deteriorates
Solution Approach 1:
Different portions of the needle assembly have different mechanical properties. The needle shaft includes a rigid portion for stability and a flexible portion for navigation. The jacket also has varying degrees of rigidity and flexibility in different segments. This local differentiation allows the needle to maintain structural stability where needed while achieving the flexibility required for anatomical navigation.
Solution Approach 2:
The needle assembly uses composite construction combining materials with different mechanical properties. The needle shaft comprises rigid and flexible segments, and the jacket uses materials that provide both sealing capability and flexibility. This composite approach enables the overall assembly to achieve both structural stability and flexibility simultaneously.
3Ease of operation
If the jacket is made more flexible to allow needle movement, then ease of operation is improved, but durability deteriorates and jacket rupture risk increases
Solution Approach 1:
By segmenting the jacket into multiple portions that can move independently, the structure can flex and bend without concentrating stress on a single continuous material. This segmentation distributes mechanical stresses across multiple discrete portions, preventing rupture while maintaining flexibility.
Solution Approach 2:
The segmented jacket structure provides built-in stress distribution and stress relief mechanisms that prevent rupture before it occurs. The separable portions act as cushioning elements that absorb and distribute bending stresses, protecting the jacket from rupture during needle manipulation.
Data Source
AI summary
The present teachings relate generally to a medical flexible needle assembly (10), comprising a needle portion (20) disposed at a distal end (12) of the assembly; a stiff portion (30) disposed at a proximal end 14 of the assembly; an flexible portion disposed between and interconnecting the needle portion and the stiff portion, including a flex distal portion (42), a flex proximal portion (44); and a jacketing member (50) disposed about the assembly (10) over at least part of the flexible portion (40); characterized in that the jacketing member (50) includes one or more coupled regions (60) and one or more decoupled region (70), wherein in at least one or more of the one or more coupled regions (60) are located proximally, distally, or both of the flexible portion (40).