In certain situations, a surgical approach placing a hole in the floor of the third (III) ventricle may relieve the buildup of excess fluid in the ventricular system without placing a shunt.
Endoscopic IIIrd Ventriculostomy
The goal is to divert excess cerebrospinal fluid out of the ventricular system into other fluid spaces which surround the outside of the brain. The neurosurgeon takes a tiny fiber optic endoscope and enters the front of the brain going into the frontal horn of the ventricle (see the labeled ventricular system to the left). This is one of the same pathways that a shunt catheter is placed when performing a shunt operation. Using the endoscope, the surgeon enters the Foramen of Monro and follows this entryway into the III Ventricle. He then uses a special instrument guided through the endoscope to make a small hole into the floor of the III ventricle.
See The New CSF Flow Pattern
Place your mouse pointer over the image to the left and press the arrow to start the animation. You can follow the CSF flow from the Frontal Horn down through the Foramen of Monro into the III Ventricle and then out of the III Ventricle through the hole in the floor.