A variable stiffness mechanism for steerable percutaneous instruments

A variable stiffness mechanism for steerable percutaneous instruments: Integration in a needle

De Falco, I. (Scuola Superiore Sant'Anna, Pisa)
Culmone, C. (TU Delft Medical Instruments & Bio-Inspired Technology)
Menciassi, Arianna (Scuola Superiore Sant'Anna, Pisa)
Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology)
van den Dobbelsteen, J.J. (TU Delft Medical Instruments & Bio-Inspired Technology)

2018

Needles are advanced tools commonly used in minimally invasive medical procedures. The accurate manoeuvrability of flexible needles through soft tissues is strongly determined by variations in tissue stiffness, which affects the needle-tissue interaction and thus causes needle deflection. This work presents a variable stiffness mechanism for percutaneous needles capable of compensating for variations in tissue stiffness and undesirable trajectory changes. It is composed of compliant segments and rigid plates alternately connected in series and longitudinally crossed by four cables. The tensioning of the cables allows the omnidirectional steering of the tip and the stiffness tuning of the needle. The mechanism was tested separately under different working conditions, demonstrating a capability to exert up to 3.6 N. Afterwards, the mechanism was integrated into a needle, and the overall device was tested in gelatine phantoms simulating the stiffness of biological tissues. The needle demonstrated the capability to vary deflection (from 11.6 to 4.4 mm) and adapt to the inhomogeneity of the phantoms (from 21 to 80 kPa) depending on the activation of the variable stiffness mechanism. [Figure not available: see fulltext.]

Minimally invasive instruments
Needle deflection
Steerable needle
Tissue inhomogeneity
Variable stiffness

http://resolver.tudelft.nl/uuid:e761755d-26da-4829-8f76-329e30d2a37c

https://doi.org/10.1007/s11517-018-1847-7

2018-12-04

0140-0118

Medical & Biological Engineering & Computing, 56 (12), 2185-2199

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2018 I. De Falco, C. Culmone, Arianna Menciassi, J. Dankelman, J.J. van den Dobbelsteen