Long-Term Efficacy of Shunt Therapy in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND: Idiopathic normal pressure hydrocephalus (iNPH) is one of the very few treatable types of dementia. Shunt therapy has been shown to be effective in improving symptoms. However, the long-term results of cerebrospinal fluid diversion are variable. The aim of this retrospective study was to investigate long-term outcomes of patients with idiopathic normal pressure hydrocephalus treated with ventriculoperitoneal shunt by using programmable valves. METHODS: Symptoms before treatment were recorded. Clinical symptoms and outcome after ventriculoperitoneal shunt were assessed based on changes in gait, urinary incontinence, and cognitive dysfunction at yearly follow-up spanning at least 10 years. RESULTS: Among 50 patients treated, 5 had died at the time of the evaluation. Median age was 71 years, and mean follow-up time of the surviving patients was 120.2 +/- 2.3 years. Overall, there was a significant and lasting improvement among all symptoms compared with the baseline (P < 0.05). Gait showed better and sustained improvement compared with the baseline (P < 0.05). Cognitive impairment and urinary incontinence improved in the early follow-up (P < 0.05) followed by declines in long-term follow-up. Ten patients (20%) required surgical revisions for shunt malfunction. Change in valve pressure was performed in 20 patients (40%). Overall, 93.3% revisions resulted in clinical improvement. CONCLUSIONS: Surgical treatment for idiopathic normal pressure hydrocephalus by ventriculoperitoneal shunt is a safe modality that improves symptoms in most patients, including in the long-term. Strict follow-up is necessary for early diagnosis of shunt malfunction or need for valve adjustment.