Endoluminal Prosthesis Deployment with Rotational Control
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Solution Overview
Problem
Current endoluminal stent graft deployment systems face challenges such as retroflex and 'bird's beak' formation due to improper alignment and curvature of the aortic arch, leading to incomplete sealing and potential failure of the prosthesis to conform to the arterial wall, especially in areas with extreme tortuosity or near the aortic valve.
Innovation Solution
The system employs a control lumen with a nose cone and supporting wires that provide longitudinal support to prevent rotation of the stent graft's proximal end during deployment, along with a retractable nose cone and inner sheath with a through-hole for perfusion, allowing for precise placement and full expansion of the stent graft within the artery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a self-expanding stent graft is constrained within a narrow diameter sheath for delivery, then the prosthesis can be delivered to the deployment site, but the proximal end of the stent graft fails to properly align with the arterial wall due to retroflex rotation
Solution Approach 1:
The delivery system pre-positions the proximal end of the stent graft against the arterial wall before full deployment. The system maintains the stent graft in a constrained state within the delivery catheter until the proximal end is properly aligned, then selectively releases the distal end first to expand while maintaining proximal alignment, preventing retroflex rotation.
Solution Approach 2:
The delivery system separates the release mechanism into proximal and distal control zones. The proximal end remains constrained against the arterial wall while the distal end is released for expansion. This segmented release allows the stent graft to expand distally while the proximal end maintains alignment, preventing rotation and ensuring proper sealing.
2Adaptability or versatility
If the stent graft is deployed in a tortuous aorta with extreme curvature, then the prosthesis reaches the target site, but the proximal end rotates backward causing failure to form a seal
Solution Approach 1:
The system pre-aligns the proximal end of the stent graft against the arterial wall in tortuous anatomy before deployment. The delivery catheter maintains the stent graft in a pre-positioned state that accounts for the curvature, ensuring the proximal end is properly oriented before selective release and expansion occurs.
Solution Approach 2:
The delivery system applies different mechanical properties to different portions of the stent graft. The proximal end is maintained in a constrained, alignment-critical state while the distal end is released for expansion. This localized control ensures proper sealing at the proximal end even in tortuous anatomy where uniform expansion would cause rotation.
3Productivity
If the nose cone and sheath are advanced to the surgical site and then retracted to deploy the prosthesis, then deployment is achieved, but the proximal end of the stent graft rotates backward toward the surgeon
Solution Approach 1:
The proximal end of the stent graft is pre-positioned and constrained against the arterial wall before the retraction and deployment sequence. This preliminary alignment ensures that when the delivery catheter is retracted and the stent graft expands, the proximal end remains fixed in the correct position and does not rotate backward toward the surgeon.
Solution Approach 2:
The system transitions from a static constrained state to a dynamic selective release state. The proximal end remains constrained during the retraction phase, then the distal end is released for expansion while the proximal end maintains its position. This dynamic control prevents the proximal end from rotating backward during the deployment process.
4Adaptability or versatility
If the stent graft is forced to conform to an inferior portion curve of the aorta, then the prosthesis reaches the curved anatomy, but a gap or bird's beak formation occurs
Solution Approach 1:
The delivery system pre-positions the stent graft to account for the inferior portion curve of the aorta before deployment. The proximal end is constrained against the arterial wall in the correct orientation, allowing the stent graft to expand and conform to the curvature without creating gaps or bird's beak formations.
Solution Approach 2:
The system applies localized control to different portions of the stent graft during deployment. The proximal end is maintained in a fixed, alignment-critical state while the distal end expands to conform to the curvature. This localized differential control allows the stent graft to adapt to the inferior portion curve while maintaining seal integrity at the proximal end.
Data Source
AI summary
A system for implanting a prosthesis includes a control lumen and a nose cone affixed at a distal end of the control lumen. At least one supporting wire is affixed at one end, is substantially parallel to a major axis of the control lumen and is free at an opposite end, wherein the free end of at least one of the supporting wires is arcuate. Alternatively, a system for implanting a prosthesis includes at least one suture extending from a nose cone affixed to a distal end of a control lumen. The suture extends from the nose cone to a proximal end to a stent graft extending about the control lumen and from the stent graft to a fixed location on the control lumen. The suture is releasable from the stent graft by remote activation, whereby the suture separates from the nose cone to thereby deploy the stent graft.