Atraumatic Mandrel with Rolling Membrane for Graft Application
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Solution Overview
Problem
Current arterial vein grafts (AVGs) suffer from high occlusion rates due to intimal hyperplasia, limiting their long-term patency and requiring additional surgical interventions, as they are prone to stenosis and diminished blood flow due to smooth muscle cell migration and proliferation in response to the arterial circulation environment.
Innovation Solution
A method involving a mandrel with a rolling membrane is used to atraumatically insert and apply a restrictive fiber matrix to a tubular conduit, such as a saphenous vein, to create a graft device that minimizes frictional forces and promotes reduced occlusion by applying a polymer or metal layer to the conduit, which can be electrospun to create a constrictive covering that matches the target vessel's diameter and reduces expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional mandrel is inserted into a tubular conduit to apply a fiber matrix, then the fiber matrix can be applied to the conduit, but the mandrel creates sliding frictional forces that cause trauma to the conduit and reduce graft patency
Solution Approach 1:
The mandrel is covered with a thin film or shell that allows it to flex and conform to the tubular conduit during insertion and application. This flexible covering reduces sliding frictional forces between the mandrel and conduit, thereby minimizing trauma while still enabling the mandrel to perform its function of applying the fiber matrix.
2Reliability
If the fiber matrix is applied to restrict conduit expansion, then occlusive events are reduced, but the application process requires precise matching to target vessel diameter
Solution Approach 1:
The system allows for adjustment of the fiber matrix properties (such as density, thickness, or composition) to match the specific requirements of the target vessel diameter. By changing these parameters, the fiber matrix can be optimized to provide the appropriate level of restriction for each patient's anatomy, preventing over-constraint or under-constraint.
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 solution enhances AVG patency by reducing occlusive events and minimizing surgical trauma, allowing for improved blood flow and reduced need for re-intervention by applying a customized, constrictive fiber matrix that matches the target vessel's diameter, thereby reducing friction and promoting stable graft integration.
Implementation Method 1
The mandrel can be constructed and arranged such that advancement of the elongate shaft causes the rolling membrane to fold over onto itself, such as to atraumatically engage the inner surface of the tubular conduit. The folding over action of the rolling membrane limits (e.g., minimizes) creation of sliding frictional forces between the rolling membrane and the tubular conduit.
Implementation Method 2
a fiber application device such as an electrospinning unit, and a restrictive fiber matrix is applied to surround the tubular conduit
Data Source
AI summary
In some aspects, a system for applying a fiber matrix on a tubular conduit is provided. The system can include a tubular conduit, a mandrel and a fiber matrix delivery assembly. The mandrel can comprise an elongate shaft and a rolling membrane configured to atraumatically engage the tubular conduit.