Steerable Catheter Shaft Reducing Foreshortening via Layered Compression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steerable endovascular delivery devices face limitations in navigating through small vessels and tight bends due to guide sheath deformation, such as kinking, foreshortening, and unpredictable movement, which hinders precise positioning of medical implants.
Innovation Solution
A steerable shaft delivery apparatus with a pull-wire conduit and a compression-resistance portion incorporated into the steerable portion, allowing for adjustable curvature and reduced foreshortening, featuring a layered structure with varying hardness and angular offset of the compression-resistance portion to enhance steerability and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the guide sheath is deflected or flexed to navigate bends in the vasculature, then steerability is improved, but the guide sheath deforms (kinks, pancakes, or foreshortens) reducing positioning precision
Solution Approach 1:
The guide sheath is divided into multiple discrete segments or layers that can move independently relative to each other. This segmentation allows the sheath to flex and navigate bends while maintaining overall structural integrity and preventing deformation of the distal end, thereby resolving the contradiction between steerability and positioning precision.
Solution Approach 2:
The guide sheath employs a nested multi-layer structure where inner layers are contained within outer layers. These nested layers can slide or flex independently, enabling the sheath to bend and steer through vasculature while the outer layers maintain the overall shape and prevent kinking or foreshortening, thus maintaining positioning precision during steering operations.
2Adaptability or versatility
If the guide sheath is made more flexible to navigate tight bends, then adaptability is improved, but structural integrity deteriorates causing unpredictable movement
Solution Approach 1:
The guide sheath utilizes composite material construction with multiple layers having different mechanical properties. The combination of flexible and structurally stable materials allows the sheath to adapt to tight bends while maintaining predictable movement characteristics and structural integrity, resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The guide sheath employs dynamic characteristics where different sections have varying degrees of flexibility and stiffness. This dynamic structure allows the sheath to adapt to bends by flexing in controlled manner while maintaining overall structural integrity and predictable movement, preventing unpredictable behavior during navigation.
3Reliability
If the guide sheath is made more rigid to maintain structural integrity, then reliability is improved, but steerability deteriorates
Solution Approach 1:
The guide sheath is segmented into multiple layers with different rigidity characteristics. This segmentation allows the sheath to maintain overall structural integrity while enabling localized flexing for steering, resolving the contradiction between reliability and steerability.
Solution Approach 2:
Different sections of the guide sheath have locally optimized properties where the proximal sections provide structural support and the distal sections provide flexibility for steering. This local quality differentiation allows the sheath to maintain structural integrity while achieving effective steerability.
Data Source
AI summary
A steerable catheter includes a shaft and a pull wire. The shaft includes a proximal portion and a distal portion. The shaft includes an inner layer that defines an inner lumen of the shaft. The shaft comprises an outer layer that defines an outer diameter of the shaft. The shaft comprises a pull-wire lumen between the inner layer and the outer layer. The pull wire extends through the pull-wire lumen. The pull wire has a proximal end portion and a distal end portion. The distal end portion of the pull wire is fixed to the distal portion of the shaft. The proximal end portion of the pull wire extends radially outward of the outer layer. Increasing tension in the pull wire curves the distal portion of the shaft.