Hybrid Wire Guide Flex Transition Voids

Solution Overview

Problem

Conventional wire guides face challenges in achieving a smooth flexible transition between stainless steel and nitinol sections, leading to poor navigation around tight corners or bends in a patient's anatomy due to inadequate flexibility and pushability when using a single material core.

Innovation Solution

A hybrid wire guide design featuring a stainless steel wire with a flex transition segment and nitinol wire, where the stainless steel wire includes a pattern of flexibility-enhancing voids along its centerline that change in shape and density to match the flexibility of the nitinol wire at the weld, ensuring a seamless transition and improved navigability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a core member made from stainless steel is used to enhance pushability, then the pushability of the proximal end portion is improved, but the flexibility of the distal end portion deteriorates

Engineering Contradiction:

ImprovepushabilityVSAvoidflexibility

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The wire guide employs a composite core member structure combining stainless steel and nitinol materials. The proximal portion uses stainless steel for high pushability, while the distal portion uses nitinol for high flexibility. This composite material approach resolves the contradiction by allowing each section to exhibit its optimal mechanical properties without compromising the other.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The core member is designed with spatially varying material properties - the proximal end portion has high elastic modulus stainless steel for pushability, while the distal end portion has low elastic modulus nitinol for flexibility. This local differentiation of material quality allows the single core member to simultaneously satisfy both pushability and flexibility requirements in different regions.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If a core member made from nitinol is used to enhance flexibility, then the flexibility of the distal end portion is improved, but the pushability of the proximal end portion deteriorates

Engineering Contradiction:

ImproveflexibilityVSAvoidpushability

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The wire guide employs a composite core member structure combining stainless steel and nitinol materials. The proximal portion uses stainless steel for high pushability, while the distal portion uses nitinol for high flexibility. This composite material approach resolves the contradiction by allowing each section to exhibit its optimal mechanical properties without compromising the other.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The core member is designed with spatially varying material properties - the proximal end portion has high elastic modulus stainless steel for pushability, while the distal end portion has low elastic modulus nitinol for flexibility. This local differentiation of material quality allows the single core member to simultaneously satisfy both pushability and flexibility requirements in different regions.

Inventive Principle:

Principle #3Local quality

3Strength

If stainless steel and nitinol wires are joined by welding, then the structural integrity is improved, but the smoothness of flexibility transition deteriorates

Engineering Contradiction:

Improvestructural integrityVSAvoidsmoothness of transition

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The transition section between stainless steel and nitinol wires features gradually changing geometric parameters - specifically, a tapered configuration where the cross-sectional area transitions smoothly from the stainless steel wire to the nitinol wire. This gradual parameter change ensures smooth flexibility transition while maintaining structural integrity at the weld junction.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

A transition section acts as an intermediary element between the stainless steel and nitinol wires. This intermediate zone provides a gradual flexibility transition, preventing abrupt changes that would occur with direct welding, while still maintaining structural integrity through proper joining.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3069750B1Flexible hybrid wire guide

Publication Date: 2018.01.31 COOK MEDICAL TECHNOLOGIES LLC

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AI summary

A hybrid wire guide is comprised of a distal segment of nitinol wire welded to a proximal segment of stainless steel wire. The stainless steel wire includes a flex transition segment that terminates at the weld, and defines a plurality of flexibility enhancing voids distributed in a pattern along a centerline so that a flexibility of the flex transition segment changes toward a match of a flexibility of the nitinol wire over a tracking segment that extends distally from the weld. The respective shapes of the flexibility enhancing voids change responsive to the flexure of the flex transition segment away from a straight configuration.