Endoscopic Third Ventriculostomy (ETV)
General Information
- Endoscopic third ventriculostomy (ETV) is an alternative to shunt placement for treatment of hydrocephalus.
- The technique opens a hole inside the brain to re-establish effective flow of cerebrospinal fluid (CSF).
ETV anatomy: This constructive interference in steady state (CISS) magnetic resonance image (MRI) shows the key points relevant to ETV. Cerebrospinal fluid (here, in white) flows from the lateral ventricle to the third and finally out the fourth (small white arrowhead) ventricles. In this patient, there is an obstruction (blockage, at tip of large white arrow) present between the third and fourth ventricles. (This channel is called the cerebral aqueduct.) When the aqueduct is narrowed or blocked, it is called aqueductal stenosis. An ETV involves making a hole in the front part of the third ventricle (black arrow), which allows the cerebrospinal fluid to leave the third ventricle, bypassing the obstructed aqueduct.
- Advantages
- No foreign object (shunt tubing and valve) implanted in the body, lowering the risk of infection.
- Fewer incisions mean slightly less discomfort.
- A lower long term complication rate compared to a shunt.
- Disadvantages
- The chances of improving may be lower with ETV compared to a shunt
- Although very unlikely, the risk of serious complications with ETV compared to a shunt operation.
Am I a Candidate for ETV?
- ETV has the highest chance of being effective in patients who demonstrate a blockage of cerebrospinal fluid (CSF) within the ventricle system (shown in the MRI above). This is known as "obstructive hydrocephalus."
- Special MRI imaging techniques are allowing physicians to detect ventricular obstructions that were previously not recognized. This advancement has resulted in more patients being offered ETV as an alternative for treatment of their hydrocephalus.
Standard MRI image (T1-weighted) of the same patient shown above. The obstruction of the aqueduct was not noticed by the radiologist. UCLA MRI scanners are capable of performing the special CISS (also called FIESTA) MRI scanning sequences.
- In some cases, ETV is offered to patients without a visible obstruction within the ventricular system. The long term effectiveness of ETV for this indication (so-called "communicating hydrocephalus") is not known, but there is some evidence that it can be successful in some patients.
- ETV can be effective in many cases of "slit-ventricle" syndrome.
How is ETV performed?
- Specially trained neurosurgeons (neuroendoscopists) perform the procedure through a single small "dime-sized" hole in the skull using an endoscope. The procedure can take as little as 30 minutes (although sometimes longer).
