Dual-Layer TIPS Stent for Adjustable Shunt Diameter Control
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Solution Overview
Problem
Existing TIPS surgery is limited by the risk of hepatic encephalopathy due to uncontrolled shunt channel size, which can be either too large, increasing hepatic encephalopathy risk, or too small, failing to reduce portal pressure effectively.
Innovation Solution
A stent system comprising a first stent body and a second stent body, where the first stent body controls the self-expansion range of the second stent body, using connectors and materials like stainless steel or cobalt-chromium alloy to ensure mechanical stability and flexibility, and a second stent body made of nickel-titanium alloy with a coating structure for controlled diameter adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the shunt channel size is increased to reduce portal pressure effectively, then the portal hypertension control is improved, but the risk of hepatic encephalopathy increases
Solution Approach 1:
The stent employs a dual-layer structure with an inner self-expanding stent and an outer constraint stent that can be adjusted independently. The outer stent's expansion can be controlled dynamically to regulate the shunt channel diameter, allowing the system to adapt between providing sufficient portal pressure reduction and limiting hepatic encephalopathy risk based on patient response
Solution Approach 2:
The invention enables continuous adjustment of the shunt channel diameter parameter by controlling the expansion degree of the outer constraint stent. This parameter change capability allows optimization of the balance between portal pressure reduction and ammonia bypass control, directly addressing the contradiction between effective treatment and complication prevention
2Object-affected harmful factors
If the shunt channel size is decreased to reduce hepatic encephalopathy risk, then the hepatic encephalopathy risk is reduced, but the portal pressure reduction effectiveness decreases
Solution Approach 1:
The adjustable dual-stent system allows dynamic modification of the shunt channel size. When hepatic encephalopathy risk arises, the outer constraint stent can be compressed to reduce the channel diameter, limiting ammonia bypass while maintaining sufficient portal pressure reduction capability through the inner stent's structural support
3Device complexity
If a fixed-size stent is used for TIPS surgery, then the device complexity is reduced, but the ability to control shunt channel size flexibly is lost
Solution Approach 1:
The stent system is divided into two functional segments: an inner self-expanding stent that provides baseline structural support and a outer constraint stent that enables size adjustment. This segmentation allows the complex function of adjustable shunt channel control to be achieved through modular components, managing overall device complexity while providing flexible adaptability
Solution Approach 2:
The inner self-expanding stent is nested within the outer constraint stent, creating a compact dual-function device. This nesting arrangement allows the adjustable size control capability to be integrated within the overall stent structure without significantly increasing the device's external complexity or deployment complexity
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 system provides stable and flexible control over shunt channel size, reducing the risk of hepatic encephalopathy while effectively managing portal hypertension.
Implementation Method 1
a first stent body and a second stent body, wherein during use, the first stent body sleeves the second stent body, and a diameter size of the first stent is used to control a self-expansion range of the second stent body
Implementation Method 2
The second stent body is formed by weaving a single strand of memory alloy
Data Source
AI summary
The present disclosure relates to a stent for a TIPS surgery, including a first stent body and a second stent body. During use, the first stent body sleeves the second stent body, to control a self-expansion range of the second stent body. The first stent body includes first connectors, intermediate connectors, and second connectors. The second stent body is formed by weaving a single strand of memory alloy. The second stent body includes a first segment and a second segment which are connected. The first segment is of a woven spiral structure, and the second segment is of a woven self-locking structure. By arranging the first stent body to include the first connectors, the intermediate connectors, and the second connectors, the first stent body can shorten to a minimal extent in a length direction during expansion. Moreover, the design of the structure, combined with a stainless steel or cobalt-chromium alloy material, facilitates mechanical diameter control and prevents creep deformation within a long period under physiological conditions, thereby effectively improving the stability of the stent for the TIPS surgery.