title: Safety and efficacy of gravitational shunt valves in patients with idiopathic normal pressure hydrocephalus: a pragmatic, randomised, open label, multicentre trial (SVASONA).
abstract: OBJECTIVE
  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.
authors: Department of Neurosurgery, Unfallkrankenhaus Berlin, Warener Str 7, Berlin 12683, Germany. johannes.lemcke@ukb.de
authors: Johannes
authors: J
authors: Lemcke
authors: Ullrich
authors: U
authors: Meier
authors: Cornelia
authors: C
authors: Müller
authors: Michael J
authors: MJ
authors: Fritsch
authors: Uwe
authors: U
authors: Kehler
authors: Niels
authors: N
authors: Langer
authors: Michael
authors: M
authors: Kiefer
authors: Regina
authors: R
authors: Eymann
authors: Martin U
authors: MU
authors: Schuhmann
authors: Andreas
authors: A
authors: Speil
authors: Friedrich
authors: F
authors: Weber
authors: Victor
authors: V
authors: Remenez
authors: Veit
authors: V
authors: Rohde
authors: Hans-Christoph
authors: HC
authors: Ludwig
authors: Dirk
authors: D
authors: Stengel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002557:Cerebrospinal Fluid Shunts / Q000009:adverse effects; D023381:Endpoint Determination; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000601:surgery; D006112:Gravitation; D006801:Humans; D006849:Hydrocephalus / Q000150:complications / Q000601:surgery; D006850:Hydrocephalus, Normal Pressure / Q000523:psychology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D014057:Tomography, X-Ray Computed
keywords: Cerebrovascular Disease; Csf Dynamics; Dementia; Neurosurgery; Randomised Trials