A retrospective outcomes review of patients with idiopathic normal pressure hydrocephalus treated with a low flow valve system

Abstract

Abstract Accepted treatment of patients with Idiopathic Normal Pressure Hydrocephalus (INPH) dictates the placement of a Ventriculoperitoneal (VP) shunt. Selection of a valve regulated system for implantation is usually determined by the treating surgeon. Data regarding the efficacy of a Low Flow Valve (LFV) are sparse. The use of this type of system may be of benefit in patients with INPH. Data from fourteen patients in the Florida Hospital NPH Program Registry with placement of a Low Flow Valve were retrospectively examined. All patients completed baselines studies to quantify gait disturbance, cognitive dysfunction, and ventriculomegaly (Evan's Ratio). Studies were repeated post three day external lumbar drain, as well as 6, 12, and 24 months post shunt placement. Significant improvement was noted in gait (Berg Balance Score) at six months and one year post shunt placement. Patients improved from a “medium― fall risk to a “low― fall risk. Significant improvement in NAB was noted at 2 years of follow up, improving from “mildly impaired― to “average―. Evan's ratio was stable throughout the study. There were no instances of over drainage or shunt infection. One shunt obstruction which necessitated surgical intervention was observed. Objective improvement in BERG and NAB appears to provide conclusive evidence of efficacy in this small group of patients with INPH treated with placement of an LFV and followed for two years. The absence of over-drainage as a related complication in this small group is encouraging.