Hydrogel Cuff Stent-Graft Resists Migration
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Solution Overview
Problem
Conventional stent-grafts face issues with migration and leakage, leading to potential rupture in abdominal aortic aneurysm repair and discomfort in ureteral applications, due to inadequate fixation and peristaltic action.
Innovation Solution
A stent-graft design featuring radially expandable cylindrical bodies with hydrophilic polyurethane hydrogel cuffs that expand upon exposure to bodily fluids, exerting a sealing force against the vessel wall to prevent migration and leakage, and reduce patient discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stent-grafts are used with frictional forces or fixation barbs for initial securing, then the device can be initially placed in position, but migration occurs away from the original position leading to leakage and potential rupture
Solution Approach 1:
The hydrogel material undergoes parameter change by absorbing water from bodily fluids, causing it to expand in volume and exert increased sealing force against the vessel wall. This dynamic parameter change transforms the cuff from a passive friction-based seal to an active expansion-based seal that adapts to physiological conditions.
Solution Approach 2:
The stent-graft combines conventional materials (metal or polymer stent body) with a hydrogel material layer. This composite structure allows the stent to provide structural support while the hydrogel provides dynamic sealing through water absorption and expansion, creating a synergistic effect that improves both position stability and sealing reliability.
2Stability of the object's composition
If curled extensions are added to ureteral stent-graft prostheses to prevent migration, then migration is reduced, but patient discomfort and irritation of the bladder or kidney increases
Solution Approach 1:
Instead of using rigid curled extensions that cause mechanical irritation, the hydrogel cuff dynamically changes its physical state by absorbing water and expanding. This parameter change provides migration prevention through controlled expansion force rather than rigid structural protrusions, thereby eliminating patient discomfort while maintaining position stability.
Solution Approach 2:
The invention replaces the mechanical curling extension system with a hydrogel-based sealing mechanism. The hydrogel absorbs water and expands to create a seal that prevents migration without requiring rigid protruding structures that would cause bladder or kidney irritation, thus substituting a biochemical mechanism for a mechanical one.
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 stent-graft effectively maintains its position, reduces migration and leakage risks, and minimizes patient discomfort by exerting a sealing force, enhancing the reliability of endovascular repairs and ureteral drainage.
Implementation Method 1
Upon exposure to an aqueous environment, the polyurethane hydrogel expands so that the outer diameter of the cuff increases by about 10-30% and exerts a sealing force against the wall of the body vessel
Implementation Method 2
A hydrophilic polyurethane hydrogel layer is disposed about at least one of the proximal and distal cuffs. Upon exposure to an aqueous environment, the polyurethane hydrogel expands so that the outer diameter of the cuff increases by about 10-30%
Data Source
AI summary
The present disclosure generally provides a stent-graft for insertion into a body vessel that comprises hydrophilic polyurethane hydrogel cuffs and an elongated cylindrical body. This stent-graft exhibits an enhanced ability to maintain its original position when placed into a patient and resist the potential of migration without causing excessive discomfort to the patient. Upon exposure to bodily fluids, the cuffs of the stent-graft expand to exert a sealing or anchoring force against the wall of the body vessel. Such a stent-graft overcomes many of the problems associated with conventional stent-grafts as currently used in many different applications, for example, endovascular repair and ureteral drainage.