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

Are there clinically relevant differences between Switcher and Counterbalancer gravitational Shunts

Gibt es Unterschiede zwischen "Switcher" und "Counterbaancer" Schwerkraftventilen, die klinisch relevant sind?

Meeting Abstract

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  • corresponding author M. Kiefer - Neurochirurgische Universitätsklinik, Universitätskliniken des Saarlandes, Homburg/Saar
  • U. Meier - Neurochirurgische Klinik, Unfallkrankenhaus Berlin, Berlin

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.-16.05

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

Published: May 4, 2005

© 2005 Kiefer 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.




Two different technical principals of gravitational valves (G-valves) have been presented: Counterbalancer- and Switcher G-valves. Objective of this prospective study was to elaborate clinical relevant differences.


30 Miethke GA-valves (counterbalancer, GAV) and 24 Miethke Dual Switch valves (Switcher, DSV) were implanted in patients with Normal Pressure Hydrocephalus (NPH). The opening pressure of the posture independent valve was 5 cm H2O in both. Indication-, complication-, follow-up- and clinical management was identical. Technical note: In the GAV the weight of the “hanging CSF column” is directly counterbalanced by the weight of a metal ball. The DSV switch (at an incline angle > 60°) from a low- to a high pressure valve to counteract hydrostatic pressure. Mean follow-up was 12±4 months. Statistics: Spearman-, Wilcoxen-, Mann-Whitney-U-test at a significance level of <0.05.


Clinical preoperative state (p=0.140), ventricular size (p=0.114), resistance to outflow (p=0.124) were similar in both. Despite only an according trend could be found (p=0.064), the different (p=0.009) patients’ age (GAV: 62±13 years, DSV: 71±9 years in average) may mainly be responsible for the better outcome (p=0.000) with the GAV (Responder rate: 94%) than with the DSV (Responder rate: 62%). Relative average ventricular size reduction was larger (p=0.016) with the GAV (11%±12) than with the DSV (5%±6). Despite moderate, postoperative ventricular size was clearly different compared to preoperative state (DSV: p=0.023; GAV: p=0.018), but without obvious influence on outcome (DSV: p=0.382; GAV: p=0.311). Overall complication rate necessitating operative revision was low with 11% (overdrainage: n=4, distal tube occlusion: n=2). However overdrainage with operative consequences occurred more often with the DSV (13%) than with the GAV (3%).


Due to the constructive principal Switcher G-valves may be more sensitive for overdrainage with intermediate body positions than Counterbalancer constructions. This may not be evident with the usage of higher opening pressures for prone position, but with the usage of such low pressure shunts it may become relevant. Against the background of an increasing evidence for better clinical result in NPH with low-pressure valves, Counterbalancer G-valves appear superior to Switcher G-valves, because they obviously allow a low opening pressure for lying with a minimal overdrainage risk.