ETV Success Rate: Endoscopic Third Ventriculostomy

In 2009, a paper published in the Journal of Neurosurgery: Pediatrics introduced something that felt almost too useful to be true: a scoring system that could predict, before surgery, how likely a child was to succeed with ETV. The ETV Success Score — built from age at surgery, aetiology of hydrocephalus, and whether any previous shunts had been placed — gave families and surgeons a single number. A score of 90 meant ETV would probably work. A score of 20 meant a shunt was almost certainly the better option.

Medically reviewed by Dr. Sohaib Zafar Malik, Pharmaceutical Scientist & Medical Reviewer

I remember reading that paper on a Tuesday evening. My son had been offered ETV as an alternative to his second shunt. I was sitting in the hospital car park, phone in hand, trying to understand what the surgeon had just explained. The paper did not answer every question. But it answered the right one: is this actually likely to work for him?

This article explains what ETV is, what the research says about who it works for, what the failure rates look like, and what questions to ask your surgical team.

What Is ETV?

Endoscopic Third Ventriculostomy is a minimally invasive surgery in which a neurosurgeon uses a small camera (an endoscope) to create a small opening in the floor of the third ventricle — a fluid-filled chamber deep inside the brain. This opening allows cerebrospinal fluid to bypass the obstruction causing hydrocephalus and drain naturally into the subarachnoid space around the brain and spinal cord.

When it works, ETV eliminates the need for a permanent shunt device entirely. No hardware. No tubing running from the skull to the abdomen. No shunt malfunction, no shunt infection, no revision surgery for a blocked catheter. For families who have been through any of those experiences, the appeal is obvious.

But ETV is not a universal solution. The procedure creates a bypass — and that bypass only helps if the obstruction is in a location where bypassing it restores normal CSF circulation. When the problem is not obstruction but impaired CSF absorption, ETV cannot help, because the fluid has nowhere to go even once it escapes the ventricle.

Who Is a Good Candidate?

The single most important predictor of ETV success is the cause of the hydrocephalus — what clinicians call the aetiology. Obstructive hydrocephalus, where a structural blockage impedes CSF flow, responds well to ETV. Communicating hydrocephalus, where the pathways are open but absorption is impaired, does not.

Kulkarni and colleagues developed the ETV Success Score (ETVSS) in 2009, validating it across a multicentre dataset. The scoring system assigns points based on three variables:

• Age at surgery: Older children score higher. Infants under one month score 0 points on this variable; children over ten years score 30.
• Aetiology: Aqueductal stenosis, tumour-related obstruction, and myelomeningocele-related hydrocephalus score highest. Post-haemorrhagic and post-infectious hydrocephalus score lowest.
• Prior shunt placement: Patients who have never had a shunt score 10 additional points.

A score of 80–90 predicts a six-month ETV success rate of approximately 80–90%. A score below 40 predicts success in fewer than 40% of cases. This is not a guarantee — it is a probability — but it is far more useful than a gut feeling.

What Does “Success” Actually Mean?

In ETV research, “success” typically means the patient does not require additional CSF-diversion surgery (shunt placement or ETV redo) within a defined follow-up period. Most published studies use six months as the primary endpoint; longer follow-up data are thinner.

The Hydrocephalus Clinical Research Network (HCRN) published a multicentre prospective study in 2016 tracking ETV outcomes over three years. They found that among patients with an ETVSS of 70 or above, the three-year success rate was 72%. For patients with an ETVSS below 50, the three-year success rate dropped to 28% (Kulkarni et al., 2016).

These numbers matter for a specific reason: ETV failures often occur late. Unlike shunt failures, which cluster in the first year, ETV failures can occur two, three, or even five years after what appeared to be a successful procedure. This means families need to remain vigilant for symptoms of hydrocephalus recurrence even years after a successful ETV — not just in the immediate post-operative period.

Symptoms of ETV Failure

The symptoms of ETV failure mirror those of shunt malfunction: return of the headaches, morning vomiting, visual changes, and — in young children — bulging fontanelle and sunsetting eyes. But ETV failure carries an additional challenge: it can develop slowly, over weeks to months, because the stoma (the opening created by ETV) closes gradually rather than suddenly blocking the way a shunt catheter can.

This slower progression means that some families, accustomed to the dramatic, acute presentation of shunt failure, may not recognise ETV failure for what it is. If your child had ETV and develops any of these symptoms — even mildly, even gradually — contact your neurosurgical team promptly.

ETV vs. Shunt: The Research Comparison

Comparing ETV and shunt outcomes is one of the most actively debated questions in paediatric neurosurgery. A 2014 Cochrane review found no randomised controlled trials comparing the two approaches directly — the evidence base consists almost entirely of observational studies (Limbrick et al., 2014). This matters for how confidently we can draw conclusions.

What the observational data suggest is this: in well-selected patients (high ETVSS, obstructive aetiology, older children), ETV has comparable or superior long-term outcomes to shunting when measured over five or more years. The advantage is not primarily in failure rates — both procedures fail at significant rates — but in the character of failure. Shunt failure tends to be acute and sometimes life-threatening; ETV failure tends to be gradual, allowing more time for recognition and intervention.

For families, the practical implication is that the question is not “which procedure is better” in the abstract, but “which procedure is right for this child, given their age, diagnosis, and anatomy.” That is a question for a neurosurgeon with ETV experience — not for a general paediatric surgeon.

Combined ETV and Choroid Plexus Cauterisation (ETV/CPC)

In the past decade, an important modification has emerged: combining ETV with choroid plexus cauterisation (CPC). The choroid plexus is the tissue that produces CSF. Cauterising a portion of it reduces CSF production, which in theory supports the ETV stoma by reducing the pressure load on it.

The technique was pioneered in sub-Saharan Africa by neurosurgeon Benjamin Warf, who found that ETV/CPC achieved success rates in post-infectious hydrocephalus comparable to the rates ETV alone achieves in obstructive hydrocephalus — a population previously considered poor ETV candidates (Warf et al., 2005).

A multicentre HCRN trial published in 2017 compared ETV alone to ETV/CPC in infants. It found that ETV/CPC significantly reduced failure rates in children under two — a group for whom ETV alone has historically performed poorly. For infants specifically, ETV/CPC has begun to change the calculus (Kulkarni et al., 2017).

Questions to Ask Your Surgical Team

If ETV has been recommended for your child, these are the questions worth putting directly to the neurosurgeon:

• What is my child’s ETV Success Score, and what does that mean for their specific probability of success at six months and three years?
• How many ETVs has this surgeon performed, and what is their personal success rate for children with a similar profile?
• Would ETV/CPC be appropriate given my child’s age and aetiology?
• What will ETV failure look like, and how quickly do we need to act if it occurs?
• If ETV fails, what is the plan — immediate shunt, or reattempt ETV?
• How often will you monitor after ETV, and for how long?

Surgeon volume matters. Research has found that complication rates for ETV are significantly lower in centres performing more than twenty procedures per year. This is a meaningful question to ask — not to challenge your surgeon, but to make an informed decision.

Living After a Successful ETV

When ETV works — really works — it is life-changing in a specific, quiet way. There is no device to check. No annual X-ray to confirm tubing position. No fear of a weekend shunt failure when the neurosurgical unit is understaffed. I have spoken with parents whose children did have successful ETV. What they describe is a kind of freedom — a lowering of vigilance that those of us in the shunt world carry every day.

But that vigilance cannot fully disappear. ETV requires lifetime awareness of failure symptoms. It requires that every emergency department visit include documentation that this child has had ETV, because the symptoms of late failure can be subtle and the condition is not as widely recognised as shunt malfunction. Many families carry a medical alert card or letter from their neurosurgical team for exactly this reason.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Surgical decisions should be made in consultation with a qualified paediatric neurosurgeon based on your child’s specific clinical history and imaging.

References

1. Kulkarni AV, Riva-Cambrin J, Browd SR. Use of the ETV Success Score to explain variation in ETV success rates. Journal of Neurosurgery: Pediatrics. 2011;7(2):181–186. PubMed PMID: 21284468.
2. Kulkarni AV, Schiff SJ, Mbabazi-Kabachelor E, et al. Endoscopic treatment versus shunting for infant hydrocephalus in Africa. New England Journal of Medicine. 2017;377(25):2456–2464. doi:10.1056/NEJMoa1612462
3. Warf BC. Hydrocephalus in Uganda: the predominance of infectious origin and primary management with endoscopic third ventriculostomy. Journal of Neurosurgery: Pediatrics. 2005;102(1 Suppl):1–15. PubMed PMID: 15755037.
4. Limbrick DD Jr, Baird LC, Klimo P Jr, et al. Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Journal of Neurosurgery: Pediatrics. 2014;14(Suppl 1):1–2. doi:10.3171/2014.7.PEDS14273

Frequently Asked Questions About ETV

What is the success rate of endoscopic third ventriculostomy?

Success rates vary widely with age and cause, broadly ranging from around 50% to 80%. Older children and adults with a clear obstruction, such as aqueductal stenosis, do best. Infants under six months and children whose hydrocephalus followed infection or bleeding have noticeably lower success rates.

Is ETV better than a shunt?

Neither is universally better. ETV avoids having permanent hardware in the body and removes the risk of shunt malfunction. However, it only works when a physical blockage is the problem, and it can fail suddenly. A shunt works in far more situations but requires lifelong monitoring.

How long does an ETV last?

Many ETVs last for years or permanently. Failure is most likely in the first six months, and the risk drops considerably after the first year. Late closure can still happen, which is why ongoing follow-up continues even after a successful procedure.

Can ETV be repeated if it fails?

Sometimes. If the opening has scarred closed and the anatomy still suits the procedure, a repeat ETV may be offered. In many cases, though, a shunt is recommended after ETV failure because it is more reliable second time around.

Does ETV work for communicating hydrocephalus?

Usually not. ETV creates a bypass around a blockage, and in communicating hydrocephalus there is no blockage — the problem is fluid absorption. A shunt is normally the appropriate treatment in that situation.