Bendable Delivery Sheath Pull Wire Segmentation
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Solution Overview
Problem
Current bendable sheaths used in medical procedures, such as heart valve replacement, face challenges in achieving precise bending and control due to limitations in pull wire design, particularly when the sheath needs to be bent extensively or when the implantable instrument is long and rigid, leading to laborious operations and reduced effectiveness.
Innovation Solution
A bendable sheath with a pull wire that has a movable section outside the tube, connected to the distal end and extending to the operating handle, and optionally accompanied by a guiding member to delimit the gap between the tube and the movable section, allowing for improved control and flexibility in bending the sheath to reach target positions within the body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pull wire is entirely constrained within the tube, then the sheath structure is simple, but the bending control effectiveness is insufficient when extensive bending is required
Solution Approach 1:
The pull wire is divided into two distinct segments: a first section extending within the tube from the distal end toward the proximal end, and a second section extending outside the tube from the proximal end to the operating handle. This segmentation allows the pull wire to effectively transmit bending forces even when the sheath is bent extensively, resolving the contradiction between simple structure and effective bending control.
Solution Approach 2:
The pull wire transitions from a one-dimensional path inside the tube to a two-dimensional path that extends outside the tube. By adding the external dimension, the pull wire can maintain effective tension and control the distal end of the sheath even when the sheath is bent at large angles, overcoming the limitation of internal constraint alone.
2Ease of operation
If the pull wire extends outside the tube, then the bending control is improved, but the risk of tissue damage increases
Solution Approach 1:
The tube serves as an intermediary protective barrier between the pull wire and the surrounding tissue. The pull wire extends outside the tube only in a controlled manner, and the tube wall protects the tissue from direct contact with the pull wire, thereby reducing the risk of tissue damage while maintaining bending control capability.
Solution Approach 2:
The tube acts as a flexible protective shell that allows the pull wire to extend externally while maintaining tissue protection. The tube's flexible nature enables it to accommodate the pull wire's external extension without compromising the protective barrier function, thus balancing control and safety.
3Ease of operation
If the sheath is pushed along the blood vessel wall, then the navigation is easier, but the ability to reach the center of the valve is compromised
Solution Approach 1:
The sheath is designed with dynamic bending capability through the pull wire mechanism. The operator can dynamically adjust the curvature and direction of the sheath by controlling the pull wire, enabling the distal end to transition from following the vessel wall to reaching the center of the valve with precise positioning control.
Solution Approach 2:
The pull wire allows changes in the sheath's geometric parameters (curvature radius, bending angle, and directional orientation). By adjusting these parameters through pull wire tension control, the sheath can adapt its path to either follow the vessel wall for easy navigation or redirect to the valve center for precise positioning.
4Manufacturing precision
If pre-shaped catheters are customized for specific blood vessel shapes, then the targeting is improved, but the adaptability to personalized anatomy is reduced
Solution Approach 1:
Instead of using fixed pre-shaped catheters, the invention employs a dynamic bending system with a pull wire that allows real-time adjustment of the catheter's shape. This enables the catheter to adapt to the specific anatomical variations of each patient while maintaining precise targeting capability through controlled bending.
Solution Approach 2:
The pull wire is segmented into internal and external sections, allowing independent control of the sheath's bending characteristics. This segmentation provides versatile control options that can be adjusted to match different personalized anatomical structures, overcoming the limitation of fixed pre-shaped designs.
Data Source
Figure 1
Figure 2a~2b
Figure 2c
AI summary
A bendable sheath and a delivery system using the bendable sheath. The bendable sheath comprises a tube body (3). The tube body (3) comprises a distal end and a proximal end. A tube wall of the tube body (3) is connected to a pull wire (8). One end of the pull wire (8) extends towards the proximal end of the tube body (3), and the other end is connected to the tube body (3) near the distal end of the tube body (3). The pull wire (8) comprises at least a section thereof disposed freely outside the tube body (3) and near the distal end of the tube body (3). The pull wire (8) in the bendable sheath comprises the section disposed freely outside the sheath tube body (3) and, when pulled, the section is disposed so as to facilitate the application of force. The section moves relative to the tube body (3), such that a force application point is adaptively changed. The present invention improves the safety and flexibility of operations when there is a large bending radius, or when using long, hard, or inflexible intervention apparatuses.