Stent with Ratchet Mechanism for Controlled Dilation
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Solution Overview
Problem
Existing medical implants, such as stents, face challenges in achieving precise dilation and maintaining stability, often leading to over-dilation and complications during implantation due to irreversible length changes during dilation.
Innovation Solution
A medical implant design featuring a base body with diametrically opposed deflection points and an adjusting mechanism that allows for controlled extension in the circumferential direction, utilizing a combination of materials like stainless steel and Nitinol, with a second expansion mechanism to secure the expanded shape and prevent recoil, ensuring safe and stable implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a stent is dilated using a telescoping ratchet mechanism that irreversibly changes the length of struts, then the stent can be expanded to provide radial force, but the dilation cannot be precisely controlled and may lead to over-dilation
Solution Approach 1:
The stent employs a dynamic adjustment mechanism that allows the struts to be lengthened in a controlled manner through defined engagement steps of the ratchet mechanism, enabling precise control over the dilation process while maintaining the ability to generate sufficient radial force for anchoring
Solution Approach 2:
The invention changes the physical state and dimensions of the struts through controlled irreversible lengthening, where the ratchet mechanism provides discrete engagement steps that allow precise parameter adjustment of the strut length during dilation, preventing over-dilation while achieving the required radial force
2Ease of operation
If the stent struts are made long and slender to achieve flexibility, then the stent can be implanted easily, but the struts become prone to bending and breaking
Solution Approach 1:
The stent transitions from a compressed delivery state to an expanded functional state through controlled strut lengthening, where the ratchet mechanism provides progressive engagement that gradually increases strut length and radial force, allowing easy implantation followed by secure anchoring without excessive strut slenderness
Solution Approach 2:
The stent is pre-compressed to a small diameter for easy delivery through catheters, then expanded in-situ using the ratchet mechanism to lengthen struts and generate radial force, separating the implantation ease requirement from the anchoring strength requirement in time and space
3Force
If the stent is over-dilated to ensure adequate anchoring, then the radial force is sufficient, but the implantation site and vessel may be damaged
Solution Approach 1:
The ratchet mechanism provides inherent feedback through its engagement steps, allowing the operator to sense and control the dilation process in discrete increments, stopping when adequate anchoring is achieved without exceeding the safe dilation limit that would cause tissue damage
Solution Approach 2:
The invention enables controlled parameter change of strut length through defined ratchet engagement steps, allowing precise adjustment of radial force to match the requirements of the implantation site without excessive force that would cause tissue damage
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 design enables precise and safe expansion of the implant, preventing over-dilation and ensuring a strong radial force for secure anchoring, reducing material stress and failure rates, while allowing for versatile expansion mechanisms to adapt to the implant site dimensions.
Implementation Method 1
a base body (16) which comprises at least two struts (70) having at least two deflection points (24, 26) which are diametrically opposed in the axial direction (22)
Implementation Method 2
a combination of materials like stainless steel and Nitinol
Data Source
AI summary
A medical implant (10a, 10b), in particular a stent (12a, 12b), for implantation in an animal body and/or human body (14a, 14b), comprising a base body (16a, 16b) which includes at least two segments (18a, 18a′, 18b, 18b′; 20a, 20a′, 20b, 20b′) having at least two deflection points (24a, 24b; 26a, 26b) that are diametrically opposed in the axial direction (22a, 22b), and at least one adjusting means (28a, 28b; 30a, 30b) that acts on the deflection points (24a, 24b; 26a, 26b) to adjust an extension (32a, 32b) of the base body (16a, 16b) in the circumferential direction (34a, 34b).