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

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.

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.

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.

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.