Expandable Introducer Sheath for Low-Trauma Large-Device Access
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Solution Overview
Problem
Percutaneous medical procedures often result in undesirable forces being applied to vessel walls due to the insertion of large medical devices, causing injury and blood leakage, necessitating the development of an introducer sheath with a reduced insertion profile and selective expansion capabilities.
Innovation Solution
An introducer sheath with a retractably expandable section featuring a layered construction, including an inner, intermediate, and outer layer, with a cut pattern that allows for radial expansion and contraction to accommodate medical devices, minimizing vessel trauma and blood leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a large medical device is inserted through the vasculature, then the device can be delivered to the target site, but undesirable forces are applied to the vessel walls causing injury
Solution Approach 1:
The introducer sheath incorporates an expandable section that can dynamically change its radial dimension. During insertion, the sheath maintains a collapsed low-profile configuration to minimize vessel trauma. Once positioned, the sheath expands to a larger diameter to accommodate the medical device, and then retracts after device delivery to minimize ongoing vessel wall forces.
Solution Approach 2:
The introducer sheath is divided into distinct functional sections: a proximal non-expandable section, a mid-section with expandable capability, and a distal section. The expandable mid-section contains frangible links that can be selectively broken to enable radial expansion, while the other sections remain structurally intact to provide stability and sealing functions.
2Ease of operation
If an introducer sheath is used to facilitate device insertion, then device delivery is enabled, but the sheath may cause blood leakage around its outer boundaries
Solution Approach 1:
The introducer sheath utilizes dynamic expansion and retraction of its mid-section to optimize both sealing and device passage capabilities. When expanded, the sheath creates an effective seal against the vessel wall to prevent blood leakage. After device delivery, the sheath retracts to minimize interference with blood flow and reduce the risk of leakage around the sheath boundaries.
3Object-affected harmful factors
If the introducer sheath is minimized in size, then vessel trauma is reduced, but the sheath cannot accommodate large medical devices
Solution Approach 1:
The introducer sheath employs a transformable structure with expandable frangible links that allow it to change its internal diameter dynamically. During insertion, the sheath maintains a small collapsed profile to minimize vessel trauma. Once positioned, the frangible links are broken to enable the sheath to expand to a larger diameter, accommodating the medical device. After device passage, the sheath retracts to its smaller configuration.
Solution Approach 2:
The expandable section of the introducer sheath utilizes a nested structure where the frangible links can be collapsed into a compact configuration during insertion, similar to nested dolls. Once expanded, these same links provide the necessary internal diameter to accommodate the medical device, effectively providing multiple size states from a single structure.
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 introducer sheath effectively reduces vessel trauma and blood leakage by expanding to accommodate large medical devices while minimizing radial force on vessel walls and ensuring adequate blood flow post-procedure.
Implementation Method 1
the outer layer of the retractably expandable section may include an elastomeric material elastically deformable when the retractably expandable section radially expands to the radially expanded configuration, and applies a radially inward force on the intermediate layer and the inner layer in the retracted configuration
Data Source
AI summary
An introducer sheath and associated methods are disclosed herein. An example introducer sheath may include an elongate shaft having a proximal end, a distal end and a lumen extending therebetween. The elongate shaft may further include a retractably expandable section disposed between the proximal end and the distal end, the retractably expandable section may include one or more layers. At least a portion of the retractably expandable section may include a cut pattern formed in the one or more layers. The retractably expandable section may accept passage of a device through the lumen along the retractably expandable section and transition from a radially collapsed configuration before passage of the device through the retractably expandable section, to a radially expanded configuration during passage of the device through the retractably expandable section, and to a radially retracted configuration after passage of the device therethrough.