Endoscopic selective sampling of human ventricular CSF: a new perspective.

Neuroendoscopy has achieved extensive acceptance among neurosurgeons as a minimally invasive technique for the treatment of patients affected by blocked hydrocephalus. During endoscopic procedures minimal CSF amounts from selected anatomic sites of the ventricles can be withdrawn. Steerable endoscopes are used and their flexibility facilitates the aspiration of CSF during the preliminary inspection through the ventricular cavities, without any interference with the surgical actions or additional risks for the patients. In this preliminary study the concentrations of melatonin and other related metabolites in the lateral ventricles, third ventricle, pineal recess and infundibular recess were examined. The data obtained from a patient affected by blocked hydrocephalus confirmed a constant and significant difference of concentration of these substances, for instance, melatonin levels were found to be much higher in the third ventricle (542 pg/mL in its centre) than in the lateral ventricle (172 pg/mL in the right ventricle). Nevertheless, instead of what we would expect, the highest melatonin concentrations were not found in the pineal recess (438 pg/mL). In the future, neuroendoscopy, beside its evident therapeutic efficacy, could open new perspectives in the study of both CSF biochemistry and physiology, allowing a highly selective approach to the various substances which are released and float in it.