Stent Graft Diameter Reduction Constraint Arrangement
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Solution Overview
Problem
The positioning of stent grafts is complicated due to their larger diameter design, making accurate placement challenging, and existing diameter reducing ties are difficult to sew and prone to errors, which can lead to adverse effects such as occlusion of branch arteries.
Innovation Solution
A temporary diameter reduction constraint arrangement for stent grafts using serpentine wires that cross each other in a criss-cross pattern within the graft material tube, secured by a guide wire cannula and adjustable sutures, allowing for precise sizing and easier deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stent graft diameter is made larger than the vessel diameter to allow for accurate sealing and relaxation, then sealing accuracy is improved, but positioning precision deteriorates
Solution Approach 1:
The constraint arrangement is pre-assembled on the stent graft before delivery, establishing precise positioning controls in advance. The wires and receiver are configured to maintain the stent graft at a controlled diameter during delivery, preventing premature expansion and ensuring accurate placement at the target site before the constraint is released
2Ease of operation
If traditional diameter reducing ties are used to assist positioning after release, then positioning capability is improved, but manufacturing complexity and time consumption increase
Solution Approach 1:
The diameter constraint function and the positioning guidance function are merged into a single integrated arrangement. The receiver serves both as a structural support during delivery and as a guide for accurate positioning at the target site, eliminating the need for separate tying operations
Solution Approach 2:
The constraint arrangement is designed to be self-retaining through the serpentine wire pattern that repeatedly loops over the receiver, creating friction and mechanical interlocking that maintains the constraint without requiring additional tying or securing operations
3Ease of operation
If diameter reducing ties are sewn during manufacture to assist positioning, then positioning assistance is improved, but manufacturing time and error risk increase
Solution Approach 1:
The manual sewing operation is replaced with a pre-configured mechanical constraint system. The serpentine wires are pre-formed and attached to the stent graft in a controlled manufacturing process, replacing the need for manual tying operations during or after implantation
Data Source
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AI summary
A temporary diameter reduction constraint arrangement for a stent graft in combination with a stent graft is disclosed. The stent graft has a proximal end and a distal end and comprises a biocompatible graft material tube and a plurality of longitudinally spaced apart self-expanding stents fastened thereto, including at least an end stent and a plurality of intermediate stents. The constraint arrangement comprises: an elongate receiver extending longitudinally within the graft material tube; a first wire extending longitudinally along the graft material tube in a first serpentine pattern; and a second wire extending longitudinally along the graft material tube in a second serpentine pattern, wherein at least one of the first and second wires repeatedly loops over the receiver along a longitudinal length of the stent graft thereby securing the stent graft to the receiver. In one embodiment there is also a plurality of loops of thread to reduce the stent graft.