A small trepan opening (18 mm in diameter) enables performing diagnostic and therapeutic procedures within the ventricular system, brain cavities where cerebrospinal fluid circulates.

Sometimes the purpose is to treat cerebrospinal fluid circulation problems (Aqueductal stenosis, tumoural obstructions or malformations, etc.) using “Bypass” procedures such as endoscopic ventriculostomy or aqueductoplasty. On other occasions it is used for endoscopic tumoural resection procedures or for obtaining endoscopic biopsies in neoformative processes or lesions of any other nature.

At the present time there are two types of endoscopes, rigid and flexible. The first are characterised by having better quality optical systems and at the same time that the instruments used in this type of endoscope enable greater manipulation as a larger number of working channels are available. On the other hand flexible endoscopes enable greater mobility inside ventricular cavities although with a lower margin for manipulation.

The main advantage of this technique is that it enables reaching the point of diagnostic/therapeutic interest with minimum manipulation of brain tissue.