The glymphatic system and biomarkers of the cerebrospinal fluid in idiopathic normotensive hydrocephalus

Idiopathic normotensive hydrocephalus is one of the most common brain diseases in older people. The most urgent issue in the study of normotensive hydrocephalus is its differential diagnosis with other neurodegenerative and vascular pathologies of the brain. Currently, more studies have examined the concentration of biomarkers in the cerebrospinal fluid of patients with idiopathic normotensive hydrocephalus and other brain diseases to understand the pathophysiological processes in the pathogenesis of neurodegenerative diseases. The overwhelming majority of these studies have focused on the biomarkers of the cerebrospinal fluid in only one anatomical area: the ventricles of the brain or the lumbar subarachnoid space. However, only a few studies have conducted a comparative assessment of the composition and concentrations of biomarkers in ventricular and lumbar cerebrospinal fluid in the same patients. We believe that the difference in the content of biomarkers in different areas may be crucial in the choice of treatment methods for patients with idiopathic normotensive hydrocephalus. The lumbar cerebrospinal fluid is more “polluted”–the content of nearly all biomarkers in the lumbar subarachnoid space is higher than that of the cerebrospinal fluid in the ventricles of the brain. Of the two most commonly used basic surgical techniques for the treatment of idiopathic normotensive hydrocephalus, ventriculoperitoneal and lumboperitoneal bypass surgery, preference is given to lumboperitoneal bypass surgery, which avoids complications associated with damage to the parenchyma of the brain and, most importantly, drains the “dirtier” cerebrospinal fluid with a higher concentration of proteins from the lumbar space. Instead of lumboperitoneal bypass surgery, we proposed a new combination of two surgical procedures–the combination of endoscopic triventriculocysternostomy and ventriculoperitoneal bypass surgery. With such a combination, we believe that drainage of the cerebrospinal fluid from the ventricles and the subarachnoid space of the cisterns of the base of the brain will be more effective than the traditional ventriculoperitoneal shunting because the concentration of proteins involved in the progression of degenerative diseases of the brain will decrease more actively.