Outcome of modern shunt therapy in patients with idiopathic normal pressure hydrocephalus 6 years postoperatively

Abstract

Objective: Shunt therapy in idiopathic normal pressure hydrocephalus (iNPH) can improve symptoms in 84% of patients 1 year postoperatively. Therefore, implantation of a ventriculoperitoneal shunt (VPS) prevents or at least prolongs the time during which patients are not dependent on care from others because of gait disorder or dementia. In this study, the medium-term results of modern shunt therapy were evaluated.

Methods: The authors retrospectively studied outcome in iNPH patients in whom VPSs were implanted. At yearly follow-up examinations over at least 6 years, clinical symptoms were recorded according to the NPH recovery rate (NPH-RR): (preoperative Kiefer Scale [KS] score - postoperative KS score)/(preoperative KS score × 10). Time and cause of death over this period were also analyzed.

Results: Among the 147 patients treated for iNPH in the period between 1997 and 2006, 69 had died at the time of the authors' survey. Sixty-one patients reached the 6-year examination. The median age was 64 years (range 33-83 years) at the time of VPS implantation and 73 years (range 41-91 years) at the time of this study. Six years after shunt implantation, the median KS score was significantly lower than the preoperative score (4.3 vs 8.1 points). Fifty-nine percent of 61 patients had an excellent outcome, 15% had satisfactory benefit, and 26% had unsatisfactory results 6 years postoperatively. Three of the 147 patients who underwent implantation of a VPS died of cerebral diseases 4-10 years postoperatively.

Conclusions: Implantation of a VPS is a safe procedure and can improve symptoms in 74% of patients with iNPH in the longer term.

Keywords: CMI = Comorbidity Index; KS = Kiefer Scale; NPH-RR = NPH recovery rate; VPS = ventriculoperitoneal shunt; iNPH; iNPH = idiopathic normal pressure hydrocephalus; medium-term results; normal pressure hydrocephalus; outcome; shunt.