[Gravity valves for idiopathic normal pressure hydrocephalus. A Prospective study of 60 patients].

OBJECTIVE Are hydrostatic valves superior to conventional differential pressure shunts in patients with normal- pressure hydrocephalus, with regard to the postoperative results of treatment and possible complications? METHODS From September 1997 to January 2002, 60 patients with idiopathic normal-pressure hydrocephalus were treated by surgical implantation of a hydrostatic valve (Miethke dual-switch valve) at the Unfallkrankenhaus Berlin. RESULTS One year after the shunt operation, the clinical picture was very good for 33% of the patients, good for 33%, satisfactory for 17%, and poor for 17%. At 20%, the rate of postoperative complications (catheter dislocations, valve infections, underdrainage and overdrainage) is still relatively high. The opening pressure of the Miethke dual-switch valve did not correlate with the postoperative results of treatment. CONCLUSION According to our experience, hydrostatic Miethke dual-switch valves are superior to conventional differential pressure shunts without an additional gravity unit, especially with regard to the treatment of patients with idiopathic normal -pressure hydrocephalus, concerning both the postoperative results of the treatment and the incidence of possible complications. With differentiated diagnosis and therapy, a clinical improvement can be achieved for 83% of such patients.