Adjustable Annuloplasty Ring with Malleable Core for Sizing Precision
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Solution Overview
Problem
Current annuloplasty rings for mitral and tricuspid valve repair lack the ability to be accurately adjusted post-implantation, leading to potential poor outcomes such as residual mitral regurgitation and the need for reoperation, due to imprecise sizing during surgical procedures.
Innovation Solution
An adjustable annuloplasty ring system featuring a malleable metal core with a cable and housing arrangement that allows real-time reshaping during or after the procedure, enabling precise adjustment of the anterior-posterior diameter to optimize valve function without requiring re-exposure of the patient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed-size annuloplasty ring is implanted during surgery, then the surgical procedure is simple and quick, but the sizing is imprecise leading to poor repair outcomes such as residual mitral regurgitation
Solution Approach 1:
The annuloplasty ring incorporates an adjustable mechanism that allows the ring size to be dynamically changed after implantation. A delivery system with a pullable cord enables the ring to be contracted from a larger implantable size to a smaller final size, allowing precise sizing to be achieved post-implantation without requiring complex pre-surgical planning or multiple ring sizes.
2Reliability
If the annuloplasty ring size is reduced to improve repair precision, then coaptation is restored, but the risk of residual regurgitation increases if the size is not precisely correct
Solution Approach 1:
The ring is delivered in a pre-expanded, easy-to-implant configuration that simplifies the surgical insertion process. After implantation, the adjustment mechanism allows the surgeon to gradually contract the ring to the precise size needed, eliminating the need to choose the exact final size beforehand and reducing the risk of improper sizing.
Solution Approach 2:
The adjustable mechanism allows for iterative adjustment of the ring size based on observed repair outcomes. The surgeon can make incremental adjustments and assess the effect on coaptation and regurgitation, providing feedback control to achieve the optimal repair without requiring perfect initial sizing.
3Strength
If a larger annuloplasty ring is implanted to ensure adequate size, then the valve structure is supported, but the anterior-posterior diameter may be excessive preventing proper coaptation
Solution Approach 1:
The ring provides strong structural support in its expanded implantable configuration, then dynamically contracts to reduce the anterior-posterior diameter to the precise level needed for proper coaptation. This allows the ring to maintain both strength during implantation and precise dimensional control during the adjustment phase.
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
This solution allows for customized fitting of the annuloplasty device to the patient's anatomy, reducing the risk of poor repair outcomes and the need for reoperation by enabling incremental adjustments to minimize regurgitation and optimize valve function post-pump.
Implementation Method 1
an inner core formed of an elastic-plastic metal having a yield strength... a dimension between the first and second sides is permanently reduced by a predetermined tension on the cable
Data Source
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Figure 4A~4B
AI summary
An annuloplasty ring for repair of mitral and tricuspid valves that can be shape adjusted once installed to fine-tune the shape and correct for small errors in the inherently imprecise sizing process. The ring has an adjustable 3D ring core of malleable metal that can be reshaped in real-time during the procedure before or after the patient is weaned off-pump by applying simple displacements to a cable and housing arrangement. The shape of the annuloplasty ring is adjusted incrementally in steps until an optimum level of regurgitation reduction is attained. Once the surgeon is satisfied with the result, the delivery system can be can easily detached from the implant and removed. The thickness of the core could be continuously variable to control how and where deformation occurs. The ring may also incorporate an expansion joint to enable a subsequent valve -in-ring procedure.