Endoscopic Third Ventriculostomy (ETV)

What is Endoscopic Third Ventriculostomy (ETV)?

Endoscopic third ventriculostomy (ETV) is a minimally invasive neurosurgical procedure that treats obstructive hydrocephalus by creating a new pathway for cerebrospinal fluid (CSF) to flow — bypassing the obstruction within the ventricular system — without implanting a permanent shunt device.

In ETV, a small high-definition endoscope is introduced through a single burr hole into the lateral ventricle (fluid pathways) and navigated through the foramen of Monro into the third ventricle. A small perforation is made in the floor of the third ventricle (ventriculostomy), creating a direct communication between the third ventricle and the basal cisterns — where CSF can flow and be reabsorbed normally.

ETV is the preferred surgical treatment for obstructive hydrocephalus in appropriate patients because it avoids the long-term complications and maintenance requirements of a permanent VP shunt. When successful, ETV is a durable and shunt-free solution.

When is ETV Recommended?

ETV is recommended for situations where by the hydrocephalus is due to an obstruction distal to the third ventricle.  In particular conditions such as:

• Aqueduct stenosis — narrowing of the cerebral aqueduct between the third and fourth ventricle; the primary indication for ETV
• Tectal or posterior fossa tumour causing CSF obstruction
• Post-haemorrhagic hydrocephalus — selected cases
• Failed or infected VP shunt requiring a non-shunt alternative

ETV is NOT effective for communicating hydrocephalus (NPH, post-meningitis) where absorption is impaired rather than flow blocked

What Happens During ETV?

Under general anaesthesia, a small burr hole is made in the skull just behind the hairline in the midline. A rigid neuroendoscope is introduced into the lateral ventricle. The anatomy within the ventricle is inspected and the endoscope navigated through the foramen of Monro into the third ventricle.

The floor of the third ventricle — a thin translucent membrane — is identified overlying the basilar artery and prepontine cistern. A small perforation is made in the floor using a balloon catheter or electrocautery, creating an opening of approximately 5 to 8mm. The endoscope is briefly advanced to confirm free CSF communication with the basal cisterns. No implant is required. The burr hole is closed and the wound sutured.

Procedure time is typically 30 to 60 minutes. Hospital stay is 2 to 3 days.

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Recovery After ETV

Hospital Stay

You will be in hospital for two to three days. Clinical improvement in hydrocephalus symptoms — headache, cognitive function, gait — may begin within days as the new CSF pathway becomes functional.  Occasionally your surgeon will leave an external drain in for the first couple of days to ensure that your CSF flow and thus pressure has returned to normal prior to removing it.

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Activity Guidelines

• Walking — from the day of surgery
• No heavy lifting for 2 weeks
• Driving — typically 2 to 3 weeks
• Return to work — 2 to 3 weeks for sedentary roles

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ETV Success Rate Assessment

Not all ETVs remain functional long-term. The ventriculostomy opening may scar over (close) over time, causing recurrence of hydrocephalus. Follow-up MRI with CSF flow studies at 3 months assesses ETV patency. Patients are instructed to recognise and report symptoms of ETV failure promptly.

Outcomes of ETV

ETV success rates vary by patient age and aetiology of hydrocephalus. In adults with aqueduct stenosis, success rates of 70–80% at 1 year are reported. ETV success probability (ETV-SP score) is calculated based on aetiology, prior shunting, and age to predict individual success likelihood. Children under 6 months have lower ETV success rates.

Risks and Complications

• Failure to establish CSF diversion — requiring VP shunt as alternative; occurs in approximately 20–30%
• Delayed ETV failure — ventriculostomy closing over time; may be sudden and life-threatening; patients must be aware of failure symptoms
• Basilar artery or thalamic perforator injury — as the arteries lie immediately beneath the floor of the third ventricle there is a risk of damage to the vessels whilst creating the ventriculostomy;  this is a rare but potentially fatal complication.
• Bleeding — from choroid plexus, fornix, or vascular injury; usually minor
• CSF leak from wound — uncommon
• Meningitis — rare

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