title: [Normal pressure hydrocephalus: prognostic value of height in patients treated with an identical shunt system].
abstract: BACKGROUND
  Normal pressure hydrocephalus (NPH) is a clinical entity frequently managed by means of a cerebrospinal fluid shunt. Hydrodynamic hypotheses consider hydrostatic pressure (as well as height) a very important variable for shunt system function. However, we did not find empirical studies supporting the influence of height on clinical response in the literature. Our objective was to study the prognostic value of height, as a variable related to hydrostatic pressure, when an identical shunt system is used.
  
  
  METHODS
  A prospective series of 61 idiopathic NPH cases was analyzed. All cases were shunted by means of a ventricle-peritoneal system with a 100mmH2O opening pressure valve. Anthropometric, clinical, radiological and pressure variables were registered, as well as delay for treatment, improvement and complications.
  
  
  RESULTS
  78.7% of cases improved after shunting. This group of patients was significantly taller (P=.005) than the group without response (median value 165cm versus 152cm). There was also a significant correlation between height and ventricular size decrease after the shunt.
  
  
  CONCLUSIONS
  In our series opening valve pressure was a constant (100mmHg) and we could consequently focus on the effect of hydrostatic pressure (height). Moreover, we found a positive predictive value for taller patients, probably because we had selected an opening pressure especially suitable for them. Current gravitational valve shunt systems also recommend considering patient height when customising the system. Our study empirically supports this idea.
authors.affiliation: Servicio de Neurocirugía, Hospital Clínico Universitario Lozano Blesa, Zaragoza, España. Electronic address: jaguas@comz.org.
authors.forename: Jesús
authors.initials: J
authors.lastname: Aguas
authors.forename: Victor
authors.initials: V
authors.lastname: Rodrigo
authors.forename: Francisco
authors.initials: F
authors.lastname: Estupiñan
authors.forename: Pere
authors.initials: P
authors.lastname: Nogues
authors.forename: Gloria
authors.initials: G
authors.lastname: Villalba
authors.forename: Javier
authors.initials: J
authors.lastname: Villagrasa
authors.forename: Luis
authors.initials: L
authors.lastname: Caral
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001827:Body Height; D001835:Body Weight; D003072:Cognition Disorders / Q000209:etiology; D004867:Equipment Design; D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology; D006112:Gravitation; D006801:Humans; D006850:Hydrocephalus, Normal Pressure / Q000150:complications / Q000601:surgery*; D006874:Hydrostatic Pressure; D007427:Intracranial Pressure; D008297:Male; D008875:Middle Aged; D011187:Posture; D011379:Prognosis; D011446:Prospective Studies; D014549:Urinary Incontinence / Q000209:etiology; D017287:Ventriculoperitoneal Shunt / Q000295:instrumentation