title: Feasibility of telemetric ICP-guided valve adjustments for complex shunt therapy.
abstract: OBJECTIVE
  The advances in shunt valve technology towards modern adjustable differential pressure (DP) valves and adjustable gravitational assisted valves result in an increasing complexity of therapeutical options. Modern telemetric intracranial pressure (ICP) sensors may be helpful in their application for diagnostic purposes in shunt therapy. We present our first experiences on telemetric ICP-guided valve adjustments in cases with the combination of an adjustable DP valve and adjustable gravitational unit.
  
  
  METHODS
  Four consecutive cases were evaluated in a retrospective review who had received a proGAV adjustable, gravitational assisted DP valve with secondary in-line implantation of an adjustable shunt assistant (proSA), together with a telemetric ICP sensor (Neurovent-P-tel) between December 2010 and June 2012 in our institution. The measured ICP values and the corresponding valve adjustments were analyzed in correlation with the clinical course and the cranial imaging of the patients.
  
  
  RESULTS
  No surgery-related complications were observed after implantation of the proSA and the telemetric ICP sensor additional to the proGAV. ICP values could actively be influenced by adjustments of the respective valve units. An increase of the position depending resistance of the proSA resulted in significant attenuated negative ICP values for the standing position, while adjustments of the proGAV could be detected not only in a supine position but also in a standing position. A clinical improvement could be achieved in all cases.
  
  
  CONCLUSIONS
  The combination of adjustability in the differential pressure valve and the gravitational unit reveals a complex combination which may be difficult to adapt only according to clinical information. Telemetric ICP-guided valve adjustments seem to be a promising tool as an objective measure according to different body positions. Further investigations are needed to select the patients for these costly implants.
authors.affiliation: Department of Neurosurgery, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Florian Baptist
authors.initials: FB
authors.lastname: Freimann
authors.forename: Matthias
authors.initials: M
authors.lastname: Schulz
authors.forename: Hannes
authors.initials: H
authors.lastname: Haberl
authors.forename: Ulrich-Wilhelm
authors.initials: UW
authors.lastname: Thomale
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D006849:Hydrocephalus / Q000601:surgery*; D007427:Intracranial Pressure; D008297:Male; D012189:Retrospective Studies; D013686:Telemetry / Q000295:instrumentation*; D017287:Ventriculoperitoneal Shunt / Q000295:instrumentation*; D055815:Young Adult