Stent With Positioning Arms For TIPS Placement
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Solution Overview
Problem
In TIPS procedures, accurately positioning the transition between the uncovered and covered portions of a stent-graft is crucial to prevent stenosis and blood clotting, as improper placement can lead to obstructed blood flow or excessive clotting, respectively.
Innovation Solution
A stent with self-expanding arms is used to facilitate precise positioning at the junction between the portal vein and the shunt, providing visual and tactile cues for accurate deployment, ensuring the transition between the covered and uncovered portions is correctly aligned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transition between uncovered and covered portions is positioned inaccurately, then the stent-graft can be implanted quickly, but stenosis or blood clotting occurs leading to shunt failure
Solution Approach 1:
The patent uses radiopaque markers that appear as distinct radiopaque lines or patterns under fluoroscopic imaging. These markers are positioned at specific locations (such as at the transition between covered and uncovered portions, or at the distal end of the stent-graft) to provide visual cues for accurate positioning during the TIPS procedure, enabling the physician to precisely locate the stent-graft relative to the shunt and portal vein junction.
2Reliability
If the uncovered portion extends into the shunt, then blood flow through the shunt is maintained, but the shunt opening stenoses and obstructs blood flow
Solution Approach 1:
Radiopaque markers are positioned to indicate the transition zone between covered and uncovered portions. By visualizing these markers fluoroscopically, the physician can control the deployment depth to ensure the uncovered portion extends sufficiently into the shunt for blood flow while stopping before the shunt opening stenoses, thus preventing the harmful effect while maintaining the beneficial blood flow.
3Reliability
If the covered portion is located within the portal vein, then blood flow is sealed within the lumen, but the covered portion blocks blood flow into the lumen and past the stent-graft
Solution Approach 1:
The radiopaque markers provide visual reference points that allow the physician to precisely position the covered portion at the appropriate location within the portal vein. This ensures the covered portion seals blood flow effectively while maintaining adequate uncovered length to allow blood flow into the lumen and past the stent-graft into the liver, preventing blockage while achieving sealing.
4Manufacturing precision
If radiopaque markers are added to the stent-graft for positioning, then positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The radiopaque markers are integrated into the stent-graft structure as simple radiopaque lines, patterns, or shapes formed during the manufacturing process. These markers provide clear fluoroscopic visibility for accurate positioning while adding minimal structural complexity to the device, as they can be incorporated into the existing stent framework or coating layers without requiring additional complex components.
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 self-expanding arms enhance the accuracy of stent-graft placement, minimizing the risk of stenosis and blood clotting, thereby maintaining effective blood flow and preventing bile duct exposure, thus ensuring the longevity of the shunt.
Implementation Method 1
A stent with self-expanding arms is used to facilitate precise positioning at the junction between the portal vein and the shunt
Data Source
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AI summary
A stent is provided with arms for positioning the stent between two passageways. The stent may also be a stent-graft with a transition between a covered portion and an uncovered portion that is positioned relative to the junction between the two passageways. The arms are self-expanding and are biased outward from the tubular wall of the stent structure. The arms engage the wall of the first passageway around the junction to the second passageway to position a portion of the stent in the first passageway and another portion of the stent in the second passageway.