Inner Insertion Member Stiffness for Kinking Prevention
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Solution Overview
Problem
Conventional medical tubular body delivering devices face issues with kinking and reduced operability due to excessive flexibility and stress concentration, which prevents effective deployment of medical tubular bodies in tortuous body lumens.
Innovation Solution
The device incorporates a second protection member that covers part of the inner insertion member between the fixing portion and the distal end of the first protection member, providing continuous stiffness and reducing the risk of kinking while maintaining operability by distributing stress and supporting the medical tubular body during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the inner insertion member is made flexible to navigate tortuous lumens, then followability is improved, but the device becomes prone to kinking and deformation
Solution Approach 1:
The patent applies local quality by providing protection members at specific locations along the inner insertion member rather than making the entire structure uniformly rigid or flexible. The first protection member is provided outside a part of the inner insertion member at a side proximal to a fixing portion, and a second protection member covers at least a part of the inner insertion member between a proximal end of the fixing portion and a distal end of a region where the first protection member is provided. This localized reinforcement allows the device to maintain flexibility where needed while preventing kinking at critical stress points.
2Reliability
If protection members are added to prevent kinking, then resistance to deformation is improved, but device complexity increases
Solution Approach 1:
The patent implements the nested doll principle by placing protection members inside the outer tube, which contains the inner insertion member. The first protection member is positioned outside the inner insertion member but within the outer tube's lumen, and the second protection member covers portions of the inner insertion member. This nested arrangement provides structural reinforcement without significantly increasing the overall device footprint or complexity, as the protection members utilize the existing spatial configuration of the delivery system.
3Strength
If the inner insertion member is reinforced to reduce kinking, then resistance to fracture is improved, but operability is reduced due to increased stiffness
Solution Approach 1:
The protection members are strategically positioned at specific locations along the inner insertion member rather than reinforcing the entire length. The first protection member is located at a side proximal to a fixing portion where the inner insertion member is fixed to the guidewire insertion member, and the second protection member covers the region between the proximal end of the fixing portion and the distal end of the first protection member's region. This localized reinforcement provides fracture resistance only where stress concentration occurs during navigation and deployment, while maintaining the flexibility and operability of the rest of the inner insertion member.
Data Source
AI summary
Provided is a medical tubular body delivering device that can prevent kinking and efficiently deploy a medical tubular body, while maintaining the reinforcing effect without reducing operability. The device has an outer tube through which the medical tubular body is disposed; a guidewire insertion member provided proximal to the medical tubular body; and an inner insertion member provided in the outer tube, and the guidewire insertion member has a penetration passage; a guidewire tube is provided in the penetration passage; the inner insertion member is partially fixed to the guidewire insertion member; a first protection member is provided outside a part of the inner insertion member proximal to a fixing portion; and at least a part of the inner insertion member between a proximal end of the fixing portion and a distal end of a region where the first protection member is provided is covered by a second protection member.