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Research paper
Safety and efficacy of gravitational shunt valves in patients with idiopathic normal pressure hydrocephalus: a pragmatic, randomised, open label, multicentre trial (SVASONA)
  1. Johannes Lemcke1,
  2. Ullrich Meier1,
  3. Cornelia Müller2,
  4. Michael J Fritsch2,
  5. Uwe Kehler3,
  6. Niels Langer3,
  7. Michael Kiefer4,
  8. Regina Eymann4,
  9. Martin U Schuhmann5,
  10. Andreas Speil5,
  11. Friedrich Weber6,
  12. Victor Remenez6,
  13. Veit Rohde7,
  14. Hans-Christoph Ludwig7,
  15. Dirk Stengel8,9
  1. 1Department of Neurosurgery, Unfallkrankenhaus Berlin, Berlin, Germany
  2. 2Department of Neurosurgery, Ernst-Moritz-Arndt-University of Greifswald, Greifswald, Germany
  3. 3Department of Neurosurgery, Asklepios Hospital Altona, Hamburg, Germany
  4. 4Department of Neurosurgery, Saarland Medical University, Homburg/Saar, Germany
  5. 5Department of Neurosurgery, Eberhard-Karls-University of Tübingen, Tübingen, Germany
  6. 6Department of Neurosurgery, Hospital Cologne-Merheim, Cologne, Germany
  7. 7Department of Neurosurgery, Georg-August-University of Göttingen, Göttingen, Germany
  8. 8Department of Trauma and Orthopaedic Surgery, Centre for Clinical Research, Unfallkrankenhaus Berlin, Berlin, Germany
  9. 9Julius Wolff Institute, Charité Medical University Centre, Germany
  1. Correspondence to Dr J Lemcke and Prof Dr U Meier, Department of Neurosurgery, Unfallkrankenhaus Berlin, Warener Str 7, Berlin 12683, Germany; johannes.lemcke{at}


Objectives To investigate whether gravitational valves reduce the risk of overdrainage complications compared with programmable valves in ventriculoperitoneal (VP) shunt surgery for idiopathic normal pressure hydrocephalus (iNPH).

Background Patients with iNPH may benefit from VP shunting but are prone to overdrainage complications during posture changes. Gravitational valves with tantalum balls are considered to reduce the risk of overdrainage but their clinical effectiveness is unclear.

Methods We conducted a pragmatic, randomised, multicentre trial comparing gravitational with non-gravitational programmable valves in patients with iNPH eligible for VP shunting. The primary endpoint was any clinical or radiological sign (headache, nausea, vomiting, subdural effusion or slit ventricle) of overdrainage 6 months after randomisation. We also assessed disease specific instruments (Black and Kiefer Scale) and Physical and Mental Component Scores of the Short Form 12 (SF-12) generic health questionnaire.

Results We enrolled 145 patients (mean (SD) age 71.9 (6.9) years), 137 of whom were available for endpoint analysis. After 6 months, 29 patients in the standard and five patients in the gravitational shunt group developed overdrainage (risk difference −36%, 95% CI −49% to −23%; p<0.001). This difference exceeded predetermined stopping rules and resulted in premature discontinuation of patient recruitment. Disease specific outcome scales did not differ between the groups although there was a significant advantage of the gravitational device in the SF-12 Mental Component Scores at the 6 and 12 month visits.

Conclusions Implanting a gravitational rather than another type of valve will avoid one additional overdrainage complication in about every third patient undergoing VP shunting for iNPH.

  • Csf Dynamics
  • Cerebrovascular Disease
  • Dementia
  • Neurosurgery
  • Randomised Trials

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