Endoscopic third ventriculostomy is a surgical procedure used to treat children who have been diagnosed with hydrocephalus caused by a blockage of the flow of cerebrospinal fluid (CSF). Instead of placing a shunt to carry the excess CSF for reabsorption in a different part of the body, an endoscopic third ventriculostomy creates a bypass for the CSF in the head, thus eliminating the need for a shunt.
Endoscopic means that the surgery is performed with the use of an endoscope. An endoscope is a thin tube that has a strong light, a powerful magnifying lens, and an opening where tiny instruments are passed.
Third ventriculostomy refers to the area of the brain where the bypass is made. Because the most common site of blockage is the narrow pathway between the third and fourth ventricle of the brain, the bypass is made through the thin membrane in the bottom (or floor) of the third ventricle. The cerebrospinal fluid may then flow from the lateral to the third ventricle and from the third ventricle through the new opening to the normal fluid chambers below the base of the brain. The cerebrospinal fluid then flows up and over the surface of the brain where it is reabsorbed into the bloodstream.