Eversion Resistant Gastrointestinal Sleeve Design
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Solution Overview
Problem
Existing gastrointestinal sleeves are prone to eversion when subjected to retrograde pressures, leading to potential blockages and complications, as they are thin-walled and have a low friction coefficient, which makes them susceptible to folding inward and obstructing the digestive tract.
Innovation Solution
The implementation of an anchor with an eversion-resistant feature, such as increased stiffness and friction coefficient, is achieved by using multiple layers of material or reinforcing members like soft, flexible wires, and texturing the surface to prevent the sleeve from everting, while maintaining a thin-walled and floppy design to avoid irritation and resistance during peristalsis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the sleeve is made thin-walled and floppy, then it causes minimal irritation and resistance during peristalsis, but it becomes prone to eversion under retrograde pressures
Solution Approach 1:
The sleeve is constructed using composite materials that combine the benefits of thin-walled flexibility with eversion resistance. The multi-layer construction includes an inner layer made of a flexible, low-friction material (such as silicone rubber or polyurethane) that minimizes irritation during peristalsis, and an outer layer or embedded reinforcement made of a stiffer material (such as polyester mesh, Dacron, or metal wire) that provides structural support and resistance to eversion under retrograde pressures.
Solution Approach 2:
The sleeve incorporates local quality variations by concentrating stiffness and reinforcement only in specific regions where eversion resistance is most needed, such as at the proximal end or at strategic intervals along the length. This allows the majority of the sleeve to remain thin-walled and floppy for minimal peristaltic resistance, while localized reinforced zones provide targeted protection against eversion forces.
2Ease of operation
If the sleeve material has a low friction coefficient, then it allows smooth passage during peristalsis, but it increases susceptibility to eversion
Solution Approach 1:
The sleeve employs composite materials where the inner surface layer maintains a low friction coefficient for smooth passage during peristalsis, while the outer layer or embedded reinforcement structures provide the necessary friction and mechanical strength to resist eversion. The combination allows the sleeve to slide smoothly through the digestive tract while the reinforced outer layer anchors it securely against retrograde forces.
3Reliability
If reinforcing members are added to increase stiffness, then eversion resistance is improved, but device complexity increases
Solution Approach 1:
The sleeve utilizes flexible shells and thin films as reinforcing members instead of bulky rigid structures. The thin-walled construction incorporates embedded mesh layers, woven fabrics, or fine wire reinforcements that provide eversion resistance while maintaining flexibility and minimizing overall device complexity. These thin-film reinforcements integrate seamlessly into the sleeve structure without requiring complex assembly or additional 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 eversion-resistant feature effectively inhibits the sleeve from everting, even under retrograde pressures, enhancing its functionality and reducing the risk of obstruction, with eversion pressures increased to 30-60 inches H2O, significantly reducing the occurrence of eversions in animal testing.
Implementation Method 1
The eversion-resistant feature may provide an increased stiffness relative to the sleeve's stiffness
Implementation Method 2
a surface of the eversion-resistant feature provides an increased coefficient-of-friction relative to that provided by the surface of the floppy sleeve itself
Data Source
AI summary
The invention relates to improved means for preventing eversion and subsequent obstruction of thin-walled, floppy gastrointestinal liners implanted in the digestive tract of an animal. The implantable devices include an anchor adapted for attachment within a natural body lumen and a thin-walled, floppy sleeve open at both ends and defining a lumen therebetween. A substantial length of the sleeve has material characteristics that result in the sleeve being prone to eversion in the presence of retrograde pressures. Exemplary eversion-resistant features provide an increased stiffness and/or an increased friction coefficient between the anchor and the proximal end of the sleeve to resist eversion. In some embodiments, the eversion-resistant feature includes an anti-buckling element, such as a wire coupled along the substantial length of the sleeve.