gms | German Medical Science

59th Annual Meeting of the German Society of Neurosurgery (DGNC)
3rd Joint Meeting with the Italian Neurosurgical Society (SINch)

German Society of Neurosurgery (DGNC)

1 - 4 June 2008, Würzburg

Vital risks of on-off-valves in Neurooncology. In vivo experience in 5 patients and in vitro testing of 8 specimen

Risiken von On-Off-Ventilen in der Neuroonkologie. Erfahrungen mit 5 Patienten und in-vitro-Untersuchung von 8 Exemplaren

Meeting Abstract

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  • corresponding author D. Hertle - Neurochirurgische Universitätsklinik Heidelberg
  • A. Unterberg - Neurochirurgische Universitätsklinik Heidelberg
  • A. Aschoff - Neurochirurgische Universitätsklinik Heidelberg

Deutsche Gesellschaft für Neurochirurgie. Società Italiana di Neurochirurgia. 59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch). Würzburg, 01.-04.06.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocP 036

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

Published: May 30, 2008

© 2008 Hertle 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.



Objective: The application of cytostatica into the prechamber in shunted tumor patients can lead to uncontrolled drainage of drugs through the shunt in the peritoneum and missing intrathecal efficacy. For this condition reversible occlusion valves were developed (Portnoy, Schulte et al., 1973). These on-off-valves have a simple mechanical switch and are at risk for unintentional occlusions. Surprisingly we found neither clinical nor test reports concerning these devices.

Methods: We tested in vitro 5 new and 3 explanted Heyer Schulte On-Off-Valves (Integra, Plainsboro, USA) using simulated typical head positions on valve. Additionally we report experiences with 5 tumor patients.

Results: In-vitro: In lateral lying position centered on the valve we observed regularly incidental switches to the "Off" position (occlusion). Excentric positions did not affect the "On" position. In-vivo: Using a retroauricular position of the devices we registered unintentional occlusions in 3 of 5 patients followed by clinical deteriorations: 1. an 11 year old patient became comatose and required helicopter rescue from holiday resort, the valve was switched to “Off”. 2. a 7-year-old patient with loss of consciousness during his stay in a pediatric clinic; 3. a patient with a Burkitt lymphoma was found deteriorated several times while under chemotherapy and a neurosurgeron had to be called to switch the valve back to "On" position. Despite bedside valve training sessions at this oncological department, nurses and physicians were not capable of operating the valve. The remaining 2 on-off-valves where placed less than two months ago and are still operating (therapy not closed).

Conclusions: The on-off-mechanism works as long as no external compression occurs. However, head positions on the valves have significant risks of unintentitonal occlusions in vivo and in vitro. We stress the importance of 1. a position near the midline/burrhole avoiding the dangerous retroauricular or occipital regions; 2. a handling training of relatives, patients, nurses and doctors; 3. removal of the device after intrathecal cytostatic treatment. More stable valves should be developed.