Self-Expanding Stent-Graft with Segmented Sheath for Vessel Repair
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Solution Overview
Problem
Existing medical devices, such as stent-grafts, have been unsuccessful in effectively addressing the need for quick and effective emergency repair of body conduits like blood vessels to prevent substantial blood loss and potential loss of limb or life during traumatic injuries.
Innovation Solution
A self-expanding stent-graft device with a metal frame covered by biocompatible graft material, designed for temporary or permanent implantation to create sutureless anastomosis, which can be manually implanted under direct visualization, and features constraining sheaths that allow for controlled deployment from a compacted state to a larger diameter to fit within the body conduit, minimizing leakage and facilitating easy insertion and deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a stent-graft is inserted into a transected blood vessel under direct visualization, then the device can quickly stop blood loss and maintain perfusion, but the device complexity increases due to the need for constraining sheaths and deployment mechanisms
Solution Approach 1:
The stent-graft is divided into multiple segments or sections that can be independently constrained and deployed. The constraining sheath is segmented to allow sequential release of different portions of the stent-graft, enabling controlled deployment from proximal to distal ends while managing the complexity of the deployment mechanism.
Solution Approach 2:
The stent-graft is nested within a constraining sheath that is itself nested within a delivery system. This multi-layer nesting allows the complex deployment mechanism to be compacted to a small profile for insertion while providing controlled deployment capability when needed, resolving the contradiction between quick blood loss control and device complexity.
2Ease of operation
If the stent-graft is deployed from the middle toward the ends, then the deployment process is simplified, but the ends of the graft may be pushed out of the ends of the blood vessel
Solution Approach 1:
The proximal end of the stent-graft is deployed and secured within the blood vessel before deploying the distal end. This preliminary action ensures that the proximal end acts as an anchor, preventing the graft from being pushed out during subsequent deployment of the distal end, while still allowing simplified sequential deployment from proximal to distal.
Solution Approach 2:
Different portions of the stent-graft have different properties: the proximal end is designed with features for initial anchoring and securement, while the distal end is designed for subsequent deployment and sealing. This local differentiation allows simplified sequential deployment while maintaining precise positioning of both ends within the vessel.
3Ease of operation
If the stent-graft is inserted in a compacted small diameter, then insertion into the blood vessel is facilitated, but the device cannot provide adequate structural support until deployed
Solution Approach 1:
The stent-graft transitions dynamically from a compacted state with small diameter for easy insertion to an expanded state with large diameter for structural support. The constraining sheath maintains the compacted state during insertion, then releases to allow expansion, providing both ease of insertion and adequate structural support at different stages of the procedure.
Solution Approach 2:
The constraining sheath acts as an intermediary that protects the stent-graft during insertion in a compacted state while enabling controlled deployment to the expanded state. This intermediary mechanism facilitates easy insertion without compromising the eventual structural support capability of the deployed stent-graft.
4Reliability
If individual balloon expanded stents are used to secure the graft ends, then the graft can be anchored, but the procedure time increases and blood loss risk increases
Solution Approach 1:
The anchoring function and the graft securing function are merged into a single integrated stent-graft structure. The self-expanding stent framework provides both structural support and anchoring capability simultaneously as the graft expands, eliminating the need for separate balloon expansion steps and reducing procedure time while maintaining anchoring reliability.
Solution Approach 2:
The stent-graft is designed to be self-anchoring through its self-expanding mechanism. As the stent expands from its compacted to expanded state, it automatically engages with the vessel wall to provide anchoring, eliminating the need for additional anchoring steps and reducing both procedure time and blood loss risk while maintaining reliable anchoring.
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 device effectively reduces blood loss and re-establishes perfusion in damaged vessels, allowing for immediate intervention in emergency situations and potentially permanent repair with minimal risk of infection, and can be used in both emergency room and field settings by trained personnel.
Implementation Method 1
A self-expanding stent-graft device with a metal frame covered by biocompatible graft material
Implementation Method 2
features constraining sheaths that allow for controlled deployment from a compacted state to a larger diameter
Data Source
AI summary
A self-expanding stent-graft provided in a diametrically compacted state for implantation and retained preferably by a constraining sheath, useful for the temporary or permanent repair of injured, partially or entirely transected body conduits including blood vessels. It may be used under direct visualization to quickly stop or substantially reduce loss of blood from such damaged vessels and to quickly re-establish perfusion distal to the injury site. The device would typically be implanted under emergency room conditions but also be used in field situations by trained medical technicians. After an end of the device is inserted into a blood vessel through the injury access, deployment preferably initiates from the device end in a direction moving toward the middle of the length of the device by directionally releasing the constraining sheath. In a preferred embodiment, the two opposing ends of the device are individually deployable from the compacted, small diameter intended for insertion into a vessel, to the larger diameter at which they fit interferably into a portion of the vessel.