A Variable Bending Stiffness Instrument: The AlKingScope

A Proof of Concept Prototype

Master thesis (2022)

Authors

A.P.M. de Koning Mechanical Engineering

Contributors

F. Trauzettel Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 1)
Di Wu Katholieke Universiteit Leuven (supervisor 1)
P. Breedveld Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 2)
A.J. Loeve Medical Instruments & Bio-Inspired Technology - Mechanical, Maritime and Materials Engineering (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2022 Alec de Koning
Additive manufacturing Variable bending stiffness Coronary interventions Mechanically steered Axial stiffness Central channel
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Published Date

08-07-2022

Language

English

Reuse Rights

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Faculty

Mechanical Engineering

Abstract

When treating a Chronic Total Occlusion (CTO) via Percutaneous Coronary Intervention (PCI), a guidewire first needs to be passed through or around the occlusion, a task requiring considerable skill and clinician experience. Proper backup support for the guidewire being used by the clinician is a prerequisite to prevent buckling or uncontrolled movement. Three different concepts that can vary their stiffness were generated, prototyped and evaluated against each other. Finally, a mechanism was designed that can vary its stiffness drastically by radially jamming wires together between a braided sheath and a radially rigid core that is also flexible in bending. Friction between the wires and the steerable segment generates the stiff configuration. If the braided sheath is released the wires can move along each other and the mechanism is flexible. The variable stiffness ability was tested by clamping the mechanism into a frame while applying a load to the distal tip. This resulted in a force-displacement curve that was 20 times stiffer in the stiff state than in the flexible state. The use of a braided sheath in a Variable Stiffness Mechanism (VSM) is an effective and
simple way to obtain variable stiffness. The proposed design is a step forward in the developing process for VSM for cardiovascular applications.