For some types of hydrocephalus, there's a surgical option that treats the problem without leaving any implant in the body: the endoscopic third ventriculostomy (ETV). For the right patient, ETV offers the appealing possibility of treating hydrocephalus without a shunt. Understanding when and how it works helps you discuss it with your team.
The core idea Remember that obstructive hydrocephalus is caused by a blockage within the ventricular system (such as aqueductal stenosis). Rather than diverting fluid out of the body with a shunt, an ETV creates a new internal pathway so CSF can bypass the blockage and reach the spaces where it's normally absorbed. In essence, it makes a new "exit door" for the trapped fluid.
How it's done ETV is a minimally invasive procedure using an endoscope — a thin tube with a tiny camera and instruments:
- Through a small opening in the skull, the surgeon guides the endoscope into the third ventricle.
- Using the camera for guidance, the surgeon makes a small opening in the floor of the third ventricle.
- This opening allows CSF to flow out of the ventricular system and into the subarachnoid space below, bypassing the blockage — restoring a route for the fluid to be absorbed.
There's no tube or valve left behind — the body's own (now rerouted) circulation handles the fluid.
Who is a good candidate ETV works best for obstructive hydrocephalus with a clear blockage that the new opening can bypass — the classic example being aqueductal stenosis. Candidacy depends on:
- The type and cause of hydrocephalus (obstructive, with a suitable blockage).
- The person's anatomy, which the surgeon assesses on imaging.
- Age and other factors — ETV success varies, and surgeons consider these in predicting whether it's likely to work (some use scoring tools to estimate the chance of success).
ETV is generally not suitable for communicating hydrocephalus, where the problem is absorption rather than a discrete blockage — those cases usually need a shunt.
The big advantage: no shunt The main appeal of ETV is avoiding a shunt and its lifelong considerations — no implant that can block or get infected in the way shunts can, and no tubing in the body. For suitable patients, a successful ETV can provide durable treatment without a device.
The honest trade-offs ETV isn't right for everyone, and it has its own considerations:
- It only works for appropriate (mainly obstructive) cases.
- The new opening can sometimes close or become ineffective over time, causing hydrocephalus to recur — so ETV can fail, sometimes years later, and ongoing awareness of symptoms remains important (covered in its own article).
- If an ETV fails, a repeat ETV or a shunt may then be needed.
- Like any brain procedure, it carries surgical risks, which your surgeon will discuss.
ETV with CPC In infants, ETV is often combined with choroid plexus cauterization (CPC) — reducing CSF production — to improve success in this age group. This combined procedure (ETV/CPC) is covered in the next article.
The takeaway ETV is an elegant, shunt-free option for suitable obstructive hydrocephalus: by creating a new internal pathway, it lets trapped CSF bypass a blockage without any implant. For the right patient, it can be an excellent choice — with the main caveats being careful candidate selection and awareness that the opening can sometimes close over time.