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

Less complications in shunt surgery: gravitational valves are proven to be effective in the therapy of the idiophatic normal pressure hydrocephalus (SVASONA)

Meeting Abstract

  • U. Meier - Neurochirurgie, Unfallkrankenhaus Berlin, Germany
  • J. Lemcke - Neurochirurgie, Unfallkrankenhaus Berlin, Germany
  • C. Müller - Neurochirurgie, Ernst-Moritz-Arndt-Universität Greifswald, Germany
  • M. Fritsch - Neurochirurgie, Ernst-Moritz-Arndt-Universität Greifswald, Germany
  • U. Kehler - Neurochirurgie, Asklepios Klinik Altona, Hamburg, Germany
  • N. Langer - Neurochirurgie, Asklepios Klinik Altona, Hamburg, Germany
  • M. Kiefer - Neurochirurgie, Universitätskliniken des Saarlandes, Homburg/Saar, Germany
  • R. Eymann - Neurochirurgie, Universitätskliniken des Saarlandes, Homburg/Saar, Germany
  • M.U. Schuhmann - Neurochirurgie, Eberhard-Karls-Universität Tübingen, Germany
  • A. Speil - Neurochirurgie, Eberhard-Karls-Universität Tübingen, Germany
  • F. Weber - Neurochirurgie, Krankenhaus Köln-Merheim, Germany
  • V. Remenez - Neurochirurgie, Krankenhaus Köln-Merheim, Germany
  • V. Rohde - Neurochirurgie, Georg-August-Universität Göttingen, Germany
  • H.C. Ludwig - Neurochirurgie, Georg-August-Universität Göttingen, Germany
  • D. Stengel - Zentrum für Klinische Forschung, Unfallkrankenhaus Berlin und Ernst-Moritz-Arndt-Universität Greifswald, Germany

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.10.06

doi: 10.3205/12dgnc375, urn:nbn:de:0183-12dgnc3751

Published: June 4, 2012

© 2012 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.



Objective: Among the dementia diseases, the idiopathic normal pressure hydrocephalus is the only entity treatable by neurosurgical therapy. Although the effectiveness of shunt surgery is unquestioned, the risk of overdrainage complications had a major influence on the indication for surgery in the past. The aim of the SVASONA study is to analyse in a randomised multi-center study whether the risk of overdrainage complications can be eliminated by the use of gravitational valves.

Methods: Patients diagnosed for iNPH by clinical examination, radiological assessment and cerebrospinal fluid (CSF) infusion test, CSF tap test and/or continuous ICP measurement were recruited in seven centers and randomly assigned to receive either a ventriculoperitoneal (vp) shunt with a programmable valve without a gravitational unit or a programmable valve with a gravitational unit. The patients were followed up 3, 6 and 12 months after surgery. The primary endpoint was the incidence of overdrainage complications after 6 months.

Results: From 2006 to 2010 150 patients were included in the study. The study was stopped according to the protocol after the planned interim analysis due to a massive advantage for the patient group with gravitational units. Six months after surgery with the intention of treating all patients, it was found that the patient group treated with programmable valves without a gravitational unit showed overdrainage complications in 32.9%, while the patient group treated with programmable valves with gravitational units showed overdrainage complications in only 2.7%. The difference was statistically highly significant (p<0.001). Underdrainage complications occurred in 4.3% of the patients without gravitational valves and in 1.4% of the patients with gravitational valves. In a per protocol analysis, the influence of cross-over patients receiving a shunt assistant due to overdrainage complications will be analyzed.

Conclusions: Significantly more patients had overdrainage complications in the treatment group without gravitational units whilst the outcome was equal in the treatment group with gravitational units. Thus through the use of gravitational units, such devices should evolve as a new standard of care for iNPH.