Expandable Sheath for Minimally Invasive Vascular Access
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Solution Overview
Problem
Minimally invasive medical procedures, such as TAVR, EVAR, and TEVAR, often cause trauma to the patient's vasculature due to shear and longitudinal forces applied by introducers with large bore access.
Innovation Solution
An introducer sheath with a coil or frame structure that can transition between a reduced diameter configuration for minimally invasive insertion and an expanded diameter configuration to accommodate larger medical devices, reducing vascular trauma while allowing for effective device delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an introducer with large bore access is used to accommodate larger medical devices, then the ability to deliver larger devices is improved, but vascular trauma increases due to shear and longitudinal forces
Solution Approach 1:
The introducer sheath employs a dynamic structure that can transition between compressed and expanded states. The coil or frame structure allows the sheath to dynamically adjust its diameter - compressed to a small profile for insertion and expanded to accommodate larger medical devices, thereby reducing vascular trauma during insertion while maintaining the ability to deliver large devices
Solution Approach 2:
The introducer sheath can be nested within a delivery system or covering sheath that provides additional support and containment. This nested configuration allows the introducer to be delivered through a smaller effective profile while still providing the necessary luminal space for large medical devices once deployed
2Object-affected harmful factors
If the outer diameter of the introducer is reduced to minimize vascular trauma, then vascular trauma is reduced, but the inner diameter becomes insufficient to accommodate larger medical devices
Solution Approach 1:
The introducer sheath transitions from a small compressed diameter for insertion (minimizing vascular trauma) to a large expanded diameter for device accommodation. The coil or frame structure enables this dynamic size change, allowing the sheath to provide both small profile during delivery and large luminal space during use
Solution Approach 2:
The physical parameters of the introducer sheath, specifically its diameter, are changed between two states: a small diameter state for insertion that minimizes vascular trauma, and a large diameter state that provides sufficient inner diameter to accommodate larger medical devices
Data Source
Figure 1
Figure 2A~2B
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AI summary
An introducer for providing access to a surgical site in a patient includes a sheath having an interior diameter that is expandable from a reduced diameter configuration to an increased diameter configuration. The introducer may be inserted into and removed from the patient while the sheath is in the reduced diameter configuration to minimize trauma to the patient's vasculature. Once inserted into the patient's vasculature, the sheath may be expanded to the expanded diameter configuration to allow for secondary devices, such as delivery devices, to be passed through the interior of the sheath. The sheath may include a frame having a mechanism to enable it to expand or collapse. The frame mechanisms may include coiled wires, flexible rings, spine structures with deflectable ribs, non-auxetic expandable and collapsible cellular patterns, and auxetic expandable and collapsible cellular patterns.