gms | German Medical Science

56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
3èmes journées françaises de Neurochirurgie (SFNC)

Deutsche Gesellschaft für Neurochirurgie e. V.
Société Française de Neurochirurgie

07. bis 11.05.2005, Strasbourg

On the optimal opening pressure of hydrostatic valves in cases of idiopathic normal-pressure hydrocephalus: a prospective study with 122 patients

Zum optimalen Öffnungsdruck hydrostatischer Ventile beim idiopathischen Normaldruckhydrozephalus: eine prospektive Studie mit 122 Patienten

Meeting Abstract

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  • corresponding author U. Meier - Department of Neurosurgery, Unfallkrankenhaus Berlin, Berlin
  • J. Lemcke - Department of Neurosurgery, Unfallkrankenhaus Berlin, Berlin
  • M. Kiefer - Department of Neurosurgery, University Homburg/Saar, Homburg

Deutsche Gesellschaft für Neurochirurgie. Société Française de Neurochirurgie. 56. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3èmes journées françaises de Neurochirurgie (SFNC). Strasbourg, 07.-11.05.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc10.05.-16.02

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

Published: May 4, 2005

© 2005 Meier 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.




Does the opening pressure of hydrostatic shunts influence the clinical outcome for patients suffering from idiopathic normal-pressure hydrocephalus?


Between September 1997 and January 2003, 122 patients with idiopathic normal-pressure hydrocephalus (iNPH) were surgically treated by implanting a hydrostatic shunt at the Departments of Neurosurgery of the Unfallkrankenhaus Berlin and the University Homburg/Saar. The results of the clinical examination, the intrathecal infusion test and the cerebrospinal tap test served as decision aids concerning the shunt implantation. As part of a prospective study, all patients were examined preoperatively, postoperatively and 1 year after the intervention.


43% of the patients showed a very good outcome, 25% a good outcome, 20% a fair outcome and 12% a poor outcome 1 year after the shunt implantation. Patients treated with an opening pressure rating of 50 mm H2O in the low-pressure stage of the gravitational valve showed a statistically significant better outcome than those with an opening pressure rating of 100 or 130 mm H2O. Of the valve-independent complications observed after the intervention (11% shunt-related complications), 8 (7%) were dislocations of ventricular or abdominal catheters, 3 (2%) were catheter tear-offs and 3 (2%) were shunt infections. Of the valve-related complications (10%), 4 patients (3%) suffered underdrainage, 8 patients (7%) showed radiological signs of overdrainage and 4 patients (3%) showed symptomatic overdrainage.


According to present knowledge, hydrostatic shunts with an opening pressure of 50 mm H2O for the low-pressure stage are the optimal therapy option for patients with iNPH. Due to the prompt switching function as soon as the patient changes his posture (lying down, standing, sitting, slanting etc.), the Miethke Gravity Assisted valve (GAV) Aesculap® is more suitable for such cases than the Miethke DualSwitch valve (DSV) Aesculap®. Can programmable gravitational valves contribute to a further optimization of the outcome while minimizing the valve-related complications?