Steerable Stylet with Reinforcing Sleeve for Kink Resistance
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Solution Overview
Problem
Current steerable medical instruments face challenges in imparting acute bends and resisting kinking, especially in larger diameter styles, which complicates navigation through tortuous pathways in the body.
Innovation Solution
A steerable elongated medical device featuring an outer tube with a cutaway slot and a reinforcing sleeve, combined with a pull wire mechanism, allows for controlled bending and anchoring within vessels, enhancing torqueability and reducing fabrication costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a small diameter stylet body is used to facilitate navigation through tortuous pathways, then the ability to impart acute bends and resist kinking is improved, but the structural strength and resistance to deformation deteriorate
Solution Approach 1:
The stylet body combines an outer tube with a reinforcing sleeve made of different materials having complementary properties. The outer tube provides flexibility and steerability, while the reinforcing sleeve adds structural strength and kink resistance. This composite structure allows the stylet to navigate tortuous pathways and impart acute bends without sacrificing structural integrity.
Solution Approach 2:
The reinforcing sleeve is positioned within the outer tube, creating a nested structure where the inner sleeve reinforces the outer tube. This nested configuration allows the stylet to maintain a compact profile while providing enhanced strength and kink resistance through the inner reinforcing element.
2Strength
If the stylet body diameter is increased to improve structural strength, then resistance to kinking is improved, but the ability to navigate tortuous pathways and impart acute bends deteriorates
Solution Approach 1:
The composite structure of outer tube and reinforcing sleeve allows optimization of each component's properties. The outer tube can be designed with smaller diameter for flexibility, while the reinforcing sleeve provides the necessary strength and kink resistance, eliminating the need to increase overall diameter.
Solution Approach 2:
The reinforcing sleeve is strategically positioned within the outer tube at locations where strength is most needed, such as the distal segment and transition zones. This localized reinforcement provides kink resistance and structural support without increasing the overall diameter or compromising flexibility in other regions.
3Strength
If a reinforcing sleeve is added to prevent kinking and enable acute bends, then structural strength is improved, but device complexity and manufacturing cost deteriorate
Solution Approach 1:
The reinforcing sleeve is inserted within the outer tube in a nested configuration, which is a straightforward assembly process. This nested design allows the components to be manufactured separately and then assembled by simple insertion, minimizing manufacturing complexity despite the added functional capability.
4Ease of operation
If the outer tube wall is made thinner to reduce diameter and improve flexibility, then ease of navigation is improved, but resistance to kinking and structural strength deteriorates
Solution Approach 1:
The outer tube can have a thinner wall for flexibility, while the reinforcing sleeve provides the necessary structural strength and kink resistance. The combination of these two components allows the stylet to achieve both flexibility for navigation and strength to prevent kinking, resolving the contradiction between thin wall design and structural integrity.
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 device enables precise steering and anchoring of medical instruments in tortuous pathways, improving the implantation of cardiac leads and guide catheters by allowing sharper bends and increased torqueability without kinking, while being cost-effective to manufacture.
Implementation Method 1
the pull wire proximal end is adapted to be manipulated to separate the pull wire proximal end from the outer tube proximal end to induce a bend in the cutaway portion
Implementation Method 2
a reinforcing sleeve positioned within the outer tube lumen and extending between a reinforcing sleeve proximal end and a reinforcing sleeve distal end, wherein the reinforcing sleeve forms a reinforcing sleeve slot portion aligned with and extending along the first portion of the outer tube slot and includes a reinforcing sleeve overlap portion extending over the second portion of the outer tube slot
Data Source
AI summary
According to an embodiment of the present invention, a steerable elongated medical device includes an outer tube extending between an outer tube proximal segment and an outer tube distal segment, and having an outer tube wall forming an outer tube lumen and an elongated outer tube slot through the outer tube wall to the outer tube lumen. The elongated outer tube slot has a first portion and a second portion and is formed between an outer tube slot proximal end and an outer tube slot distal end and extends axially along the outer tube distal segment through an outer tube slot length to define a cutaway portion of the outer tube. A reinforcing sleeve is positioned within the outer tube lumen and extends between a reinforcing sleeve proximal end and a reinforcing sleeve distal end. The reinforcing sleeve forms a reinforcing sleeve slot portion aligned with and extending along the first portion of the outer tube slot and includes a reinforcing sleeve overlap portion extending over the second portion of the outer tube slot. A handle is coupled to the outer tube proximal end, and a pull wire is positioned within the outer tube lumen and extends between a pull wire proximal end coupled to the handle and a pull wire distal end comprising a guidewire tip. The pull wire extends through the reinforcing sleeve lumen, the outer tube lumen, and a distal pull wire stop, and the guidewire tip extending distally from the distal pull wire stop and the pull wire proximal end is adapted to be manipulated to separate the pull wire proximal end from the outer tube proximal end to induce a bend in the cutaway portion.