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55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

Shift of calibration and zero reference in intraparenchymal microsensors for intracranial pressure monitoring in clinical practice

Nullwert- und Kalibrationsverschiebung bei der Anwendung intraparenchymatöser Hirndruckmesssonden in der praktischen Anwendung

Meeting Abstract

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  • corresponding author Daniel Wertheimer - Neurochirurgische Klinik, Universitäts-Krankenhaus Hamburg-Eppendorf
  • A. Giese - Neurochirurgische Klinik, Universitätsklinikum Lübeck
  • M. Westphal - Neurochirurgische Klinik, Universitäts-Krankenhaus Hamburg-Eppendorf

Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocP 07.72

The electronic version of this article is the complete one and can be found online at:

Published: April 23, 2004

© 2004 Wertheimer et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




According to the manufacturer's information intraparenchymal microsensors used for ICP-monitoring tend to drift in zero reference up to 1 mmHg over a period of 9 days. This implies that sensors used longer than 9 days may have a reduced reliability and accuracy, because of the fact that a recalibration or verification of the zero reference is not possible in an implanted sensor.


We therefore examined 16 patients with intraparenchymal ICP-Codman sensors implanted for 10 to 16 days and 14 patients with intraparenchymal microsensors in place for 17-24 days (13 females, 17 males, with a mean age of 49 years ±7,2 y). Immediately after removal of the microsensors measurements were performed in a scaled water bath at 0.5 cm and 10 cm depth at 37 ºC and the pressure readings of the microsensors was obtained and the deviation of values from 0.5 and 10 cm respectively was calculated.


The mean shift of zero reference for all sensors tested was 0,64 ±0,42 mm Hg. In the group of the patients with sensors implanted for 10 to 16 days, the mean shift at 0.5 cm was 0,59 ±0,40 mm Hg. In the group of patients with sensors in place between 17 and 24 days, a shift of 0,68 ±0,44 mm Hg was found. This difference was not significant. For measurements at 10 cm depth we found a drift of 0.8 ±0,7 mm Hg for all sensors analyzed. No significant difference was found between the two groups.


In conclusion the deviation of zero reference and loss of calibration in sensors placed between 10 and 24 days was much lower than expected based on the manufacturer information. Our findings of a minimal and non-significant difference between the groups suggest that there may be no linear correlation between duration of placement and deviation of measurements with sensors in place for less than 24 days.