Endoscopic third ventriculostomy versusVentriculoperitoneal shunt in patients with idiopathic normal pressure hydrocephalus. A systematic review

Abstract

Idiopathic normal pressure hydrocephalus (INPH) is an adult onset syndrome of uncertain origin involving non-obstructive enlargement of the cerebral ventricles. In the absence of papilledema and with normal cerebrospinal fluid (CSF) opening pressure on lumbar puncture. Hakim and Adams first described the syndrome of NPH in 1965 as a syndrome characterized by a clinical triad of progressive gait disturbance, dementia and urinary incontinence. These symptoms vary in severity and appearance. Gait impairment is the most common clinical feature in INPH, with a frequency ranging from 80% to 100% and it is often the patient’s initial complaint. The second most frequent symptom is cognitive impairment, which ranges from 42% to 100%. Urinary incontinence ranges from 34% to 82%, where full clinical triad is present in 38-82% of cases. The pathophysiology of INPH remains unknown, and the assessment of these patients is still debated, however suggested mechanisms include reduction of blood flow leading to reduced periventricular metabolism and axonal degeneration without significant cortical damage and stretching of the periventricular white matter. Diagnosis of INPH can be achieved through detailed history, physical examination, and neuroimaging which is considered as an obligatory part in the evaluation of suspected INPH to document ventricular enlargement, to rule out macroscopic obstruction to CSF flow and other pathology. Magnetic resonance imaging (MRI) is considered the method of choice due to the vastness of information it provides, but computed tomography (CT) is an acceptable alternative. Prognostic tests like the CSF tap test, the lumbar infusion test and intracranial pressure (ICP) monitoring have made it easier to identify the patients who will most likely benefit from surgery.