In-Vivo Electrical Impedance Measurement in Mastoid Bone

Wyss, Thomas; Anso, Juan; Muntane, Enric; Gavaghan, Kate; Weber, Stefan; Stahel, Andreas; Büchler, Philippe (2017). In-Vivo Electrical Impedance Measurement in Mastoid Bone. Annals of biomedical engineering, 45(4), pp. 1122-1132. Springer 10.1007/s10439-016-1758-4

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Nerve monitoring is a safety mechanism to detect the proximity between surgical instruments and important nerves during surgical bone preparation. In temporal bone, this technique is highly specific and sensitive at distances below 0.1 mm, but remains unreliable for distances above this threshold. A deeper understanding of the patient-specific bone electric properties is required to improve this range of detection. A sheep animal model has been used to characterize bone properties in vivo. Impedance measurements have
been performed at low frequencies (<1 kHz) between two electrodes placed inside holes drilled into the sheep mastoid bone. An electric circuit composed of a resistor and a Fricke
constant phase element was able to accurately describe the experimental measurements. Bone resistivity was shown to be linearly dependent on the inter-electrode distance and the local bone density. Based on this model, the amount of bone material between the electrodes could be predicted with an error of 0.7 mm. Our results indicate that bone could be described as an ideal resistor while the electrochemical processes at the electrode-tissue interface are characterized by a constant phase element. These results should help increasing the safety of surgical drilling procedures by better predicting the distance to critical nerve structures.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research > ARTORG Center - Image Guided Therapy
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Surgical Technology & Biomechanics ISTB [discontinued]
10 Strategic Research Centers > ARTORG Center for Biomedical Engineering Research

UniBE Contributor:

Wyss, Thomas Werner, Anso, Juan, Gerber, Kate, Weber, Stefan (B), Stahel, Andreas, Büchler, Philippe


500 Science > 530 Physics
500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health
600 Technology > 620 Engineering








Juan Anso

Date Deposited:

27 Dec 2016 11:42

Last Modified:

29 Mar 2023 23:35

Publisher DOI:


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