Surgical Outcome of Idiopathic Normal Pressure Hydrocephalus according to the Shunt Devices

ABSTRACT

OBJECTIVE: To determine the effect of shunt devices on the surgical outcome in the idiopathic normal pressure hydrocephalus(NPH), the authors present a retrospective analysis of 39 elderly patients who underwent shunt operations between November 1994 and May 2000, retrospectively. METHODS: The patients enrolled in this study did not have the history of intracranial hemorrhage, head injury, infection, cerebral infarction and brain tumor. The mean age was 69.9(range52-89) years. Thirteen patients who received operations with simple pressure-control shunt valves(Group I), 22 patients with siphon-control shunt valves(Group II), and four patients with flow-regulating shunt valves (Group III). Final outcome with the clinical improvement and shunt associated complications were evaluated at the last follow-up and the mean follow-up period was 14.7 months. RESULTS: Signs or symptoms of shunt dysfunction were found in eight of 39 patients(20.5%) in the subsequent course. In group I, five out of 13 patients had suffered from symptomatic subdural hematomas and one from overdrainage symptoms(46.2%);in group II, two out of 22 from underdrainage(9%);in group III, one out of four from symptomatic subdural hematomas(25%). Five patients required operative shunt revisions and five underwent burr-hole trephinations for subdural hematomas. Clinical improvements were observed in 10(79.6%), 19(86.4%), and 3(75%) patients in group I, II, and III respectively. Surgical outcomes were better for patients with siphon-control shunt valves than there with the other shunt valves in terms of shunt associated complications and functional improvements(p=0.05). CONCLUSION: The shunt operation with siphon-control shunt valves might be good for the elderly patients with idiopathic NPH.