Congenital Hydrocephalus

If your baby has been diagnosed with hydrocephalus — whether before birth, in the NICU after a premature delivery, or because their head is growing faster than expected — here is what you need to know about the condition, the two main operations used to treat it, and why the team managing your child's care matters for decades, not just the first surgery.

What Is Congenital Hydrocephalus?

Hydrocephalus is a buildup of cerebrospinal fluid (CSF) inside the brain's ventricles. It affects roughly 1 in every 1,000 babies born in the U.S. In hydrocephalus, the fluid can't get out of the ventricles or the body can't reabsorb it fast enough. CSF builds up, the ventricles swell, and pressure rises inside the skull.

Congenital means the condition is present at or near birth. The treatment and outlook depend heavily on why it developed.

At a Glance

Hydrocephalus is a buildup of cerebrospinal fluid (CSF) inside the brain's ventricles — it affects roughly 1 in every 1,000 babies born in the U.S.
The most common causes in infants are bleeding from prematurity, aqueductal stenosis, Dandy-Walker malformation, and spina bifida.
The two main operations are a ventriculoperitoneal (VP) shunt — a permanent drainage tube — and endoscopic third ventriculostomy (ETV), sometimes combined with choroid plexus cauterization (CPC).
Shunts work well but fail over a lifetime — roughly half need a revision within 2 years.
Most children with treated hydrocephalus go to regular schools, though many need extra support.

Symptoms

In newborns and infants:

A head that's growing too fast
A bulging or tense soft spot (fontanelle)
Eyes that appear to look down ('sunsetting sign')
Poor feeding, vomiting or irritability

In toddlers and older children:

Morning headaches, sometimes with vomiting
Changes in vision or double vision
Trouble with balance or walking
A drop in school performance

If your child has a shunt and suddenly develops headaches, vomiting, irritability, or unusual sleepiness, treat it as an emergency.

Diagnosis

Types

Non-communicating (obstructive) hydrocephalus — physical blockage inside the ventricular system
Communicating hydrocephalus — fluid flows out of ventricles but body can't reabsorb it downstream
Post-hemorrhagic hydrocephalus of prematurity (PHH) — most common cause in the U.S.
Aqueductal stenosis — narrowing of the cerebral aqueduct, often present before birth
Dandy-Walker malformation — developmental malformation of the cerebellum and fourth ventricle
Myelomeningocele-associated hydrocephalus — ~80% of babies born with open spina bifida also develop hydrocephalus
Post-infectious hydrocephalus — follows meningitis or in-utero infection

Treatment

VP Shunt — the workhorse

A VP shunt is a soft silicone tube that drains CSF from the ventricles to the abdomen. Shunts work immediately and are right for most babies. However, roughly half of all shunts placed in children need a revision within 2 years, and infected shunts (~5%) must be removed.

Endoscopic third ventriculostomy (ETV)

Instead of implanting hardware, the surgeon makes a small opening in the floor of the third ventricle, allowing CSF to drain naturally. Works best for older children with non-communicating hydrocephalus. Success predicted by the ETV Success Score (ETVSS).

ETV with choroid plexus cauterization (ETV/CPC)

Developed by Dr. Benjamin Warf, this variation also shrinks the choroid plexus (CSF-producing tissue) during the same endoscopic surgery. Transforms care for infants, particularly those with aqueductal stenosis and myelomeningocele.

Outcomes

Outcome	Typical result	What to know
Gross total resection (transcranial)	~90-95%	Simpson grade 1 or 2 achievable in most cases
Gross total resection (endoscopic endonasal)	~70-85%	Best for smaller, midline tumors
Visual improvement when affected	~60-80%	Higher after endonasal decompression in selected cases
Preservation of olfaction (transcranial, unilateral)	~30-50%	Best when preoperative smell preserved on uninvolved side
5-year recurrence-free survival (complete resection)	>90%	Very good when Simpson 1 achieved
10-year recurrence (modern series)	~5-15%	Long-term MRI follow-up essential

The biggest predictor of long-term control is whether the tumor and dural attachment are completely removed the first time.

References

Nakamura M, et al. Olfactory groove meningiomas: clinical outcome and recurrence rates. Neurosurgery. 2008;62(6 Suppl 3):1224-1232. PMID: 18695543
Koutourousiou M, et al. Endoscopic endonasal surgery for olfactory groove meningiomas: outcomes in 50 patients. Neurosurg Focus. 2014;37(4):E8. PMID: 25391163
Bamimore MA, et al. Smell outcomes in olfactory groove meningioma resection: systematic review and meta-analysis. World Neurosurg. 2022;160:22-32. PMID: 35033688
Khan DZ, et al. The endoscope-assisted supraorbital 'keyhole' approach for anterior skull base meningiomas: updated meta-analysis. Acta Neurochir. 2021;163(3):661-676. PMID: 32889640
Goldbrunner R, et al. EANO guideline on the diagnosis and management of meningiomas. Neuro-Oncology. 2021;23(11):1821-1834. PMID: 34181733

Our Specialists

Peleg Horowitz, MD, PhD

Neurosurgery

Bakhtiar Yamini, MD

Neurosurgery

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