Helical Stent Orthogonal Ends Segmentation

Solution Overview

Problem

Helically wound stents with ends not substantially perpendicular to the longitudinal axis are inefficient to manufacture, often requiring multiple waveform changes and resulting in raw wire ends that can damage vessels or catheters.

Innovation Solution

A helically wrapped stent design featuring a central segment with a first waveform and end segments with distinct second waveforms, connected using crimp connectors to ensure ends are orthogonal to the stent axis without exposed raw wire ends, allowing bulk manufacturing and efficient assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a single wire is used with multiple waveform changes to create end segments, then the stent ends can be orthogonal to the longitudinal axis, but the manufacturing process becomes complex and time-consuming

Engineering Contradiction:

Improveorthogonal end orientationVSAvoidmanufacturing process complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The stent is divided into three distinct segments: a central segment with constant amplitude waveform and two end segments with varying amplitude waveforms. This segmentation allows each segment to be manufactured separately using standardized processes, then assembled together. The end segments are formed by wrapping wire around a mandrel with pins arranged to create the desired varying amplitude pattern, while the central segment uses a different pin arrangement, enabling modular manufacturing without complex waveform changes in a single continuous wire.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A mandrel with specifically arranged pins serves as an intermediary tool during the forming process. The pins on the mandrel define the waveform pattern by contacting the wire at specific points during helical wrapping. By changing the pin arrangement on the mandrel, different waveform patterns (constant amplitude for central segment, varying amplitude for end segments) can be created using the same basic wrapping process, simplifying manufacturing compared to directly forming complex waveforms in a single wire.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Shape

If a single wire with multiple waveform changes is used, then orthogonal ends can be achieved, but the manufacturing time and efficiency decrease

Engineering Contradiction:

Improveorthogonal end orientationVSAvoidmanufacturing efficiency

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The stent is divided into three distinct segments: a central segment with constant amplitude waveform and two end segments with varying amplitude waveforms. This segmentation allows each segment to be manufactured separately using standardized processes, then assembled together. The end segments are formed by wrapping wire around a mandrel with pins arranged to create the desired varying amplitude pattern, while the central segment uses a different pin arrangement, enabling modular manufacturing without complex waveform changes in a single continuous wire.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The end segments are pre-formed with the correct varying amplitude waveform pattern using a mandrel with appropriately arranged pins before assembly. This preliminary formation of standardized end segment components allows for efficient batch production of end segments that can be quickly assembled with central segments of different lengths, rather than forming complete stents with multiple waveform changes in a single continuous process for each individual stent.

Inventive Principle:

Principle #10Preliminary action

3Shape

If end segments are made separately and attached to the central segment, then orthogonal ends can be achieved, but exposed raw wire ends may damage vessels or catheters

Engineering Contradiction:

Improveorthogonal end orientationVSAvoidvessel damage from raw wire ends

Core Design Contradiction:

ShapeVSObject-affected harmful factors

Solution Approach 1:

The raw wire ends at the junctions between segments, which could potentially cause damage, are converted into a beneficial feature by being enclosed within crimp connectors. These connectors contain the wire ends and provide a smooth, biocompatible surface that eliminates the harmful effect of exposed raw wires while maintaining the orthogonal end orientation benefit of segmented construction.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Crimp connectors serve as intermediary components between the wire segments. These connectors encapsulate the raw wire ends, providing a protective interface that prevents direct contact between the potentially harmful wire ends and the vessel or catheter, while still allowing the structural benefits of segmented construction with orthogonal ends to be realized.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2916780A2Helical stent with orthogonal end and method of forming stent

Publication Date: 2015.09.16 MEDTRONIC VASCULAR INC

AI summary

A helical stent includes a central segment having a first tubular waveform and a first end segment having a second tubular waveform. The waveforms are defined by a plurality of struts and a plurality of crowns connecting adjacent struts together. The struts of the second tubular waveform have different lengths such that second tubular waveform includes a plurality of amplitudes. The second tubular waveform comprises a complete turn around a longitudinal axis of the stent. A first connector connects together the first tubular waveform first end, the second tubular waveform first end, and the second tubular waveform second end. Due to the configuration of the second tubular waveform of the first end segment, the stent end at the first end segment is substantially orthogonal to the longitudinal axis of the stent. A second end segment similar to the first end segment can be connected to a second end of the first tubular waveform.