gms | German Medical Science

63rd Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Japanese Neurosurgical Society (JNS)

German Society of Neurosurgery (DGNC)

13 - 16 June 2012, Leipzig

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Flow-related noise in patients with ventriculopertioneal shunts using gravitational adjustable valves

Meeting Abstract

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  • F. Stockhammer - Klinik für Neurochirurgie, Universitätsmedizin Göttingen
  • C. Miethke - Christoph Miethke GmbH & Co KG, Potsdam
  • T. Knitter - Christoph Miethke GmbH & Co KG, Potsdam
  • V. Rohde - Klinik für Neurochirurgie, Universitätsmedizin Göttingen
  • C. Sprung - Klinik für Neurochirurgie, Charité - Universitätsmedizin Berlin

Deutsche Gesellschaft für Neurochirurgie. Japanische Gesellschaft für Neurochirurgie. 63. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Japanischen Gesellschaft für Neurochirurgie (JNS). Leipzig, 13.-16.06.2012. Düsseldorf: German Medical Science GMS Publishing House; 2012. DocSA.10.03

doi: 10.3205/12dgnc372, urn:nbn:de:0183-12dgnc3722

Published: June 4, 2012

© 2012 Stockhammer et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

Text

Rare side effects of ventriculoperitoneal shunts are noises arising from the valve. We investigated patients after implantation of a pro-GAV valve for occurrence and the possible factors related to noise development.

39 patients were asked for any noise arising from the valve. The valve was auscultated in various positions. The position of the gravitational unit (GU) was determined in respect to the Frankfurt horizontal plane (FHP). The posterior tilt of the GU in head reclination (αrecl) was calculated. Ex vivo an explanted valve was perfused with different pressures. The flow was measured, noises were recorded and the insides of the adjusting unit was observed.

3/39 (7.6%) patients reported an audible noise. Noises only occurred in up-right position with maximum head reclination. In 2/3 patients the noise was audible for the investigator (FS) with a prepared stethoscope. In all patients the αrecl varied from 4 to 108° (median 57.2°). Patients reporting a noise had a larger αrecl (median: 89 vs. 47°, p=0.0199, t-test). ROC analysis revealed a negative predictive value of 1.0 (95% CI 0.83 to 1.0) for noises if αrecl is smaller than 58.4°. In vitro the noise occured reproducible at a flow rate of 200 ml/h. By observation the ball in cone valve was the source of the noise.

Valve-related noises are rare events in patients with proGAV valves. The noise is propelled by abnormal high flow rates and can be prevented by avoiding posterior tilt of the gravitational unit especially in patients with a good cervical mobility.