Why Combine CPC With ETV in Infants With Hydrocephalus?

If your infant has been recommended an Endoscopic Third Ventriculostomy (ETV) along with Choroid Plexus Cauterization (CPC), it is because a young baby’s brain handles cerebrospinal fluid (CSF) differently than an older child’s brain. While an ETV creates a new pathway for fluid to bypass a blockage (such as aqueductal stenosis), a baby’s developing body sometimes cannot absorb that fluid fast enough on its own ^[1]. CPC is a procedure added to carefully deactivate some of the tissue that produces this fluid, slowing down its production ^[2]. By decreasing the amount of fluid produced, the infant’s maturing absorption system has a better chance of keeping up, which may increase the likelihood that the ETV will be successful without needing a permanent shunt ^[3].

The Challenge: How Infants Absorb Fluid

In older children and adults, an ETV alone is often enough to treat hydrocephalus caused by a blockage. An ETV creates a tiny opening in the floor of the third ventricle (a fluid space deep in the brain), allowing trapped fluid to bypass the narrowed aqueduct of Sylvius and flow into the spaces just outside the brain where it can be absorbed ^[4].

However, infant CSF absorption is complex and still developing. One proposed reason ETVs can fail in babies is that the specialized structures responsible for absorbing fluid into the bloodstream—called arachnoid granulations—are immature. Imaging studies show that these structures often are not fully visible or developed until a child is older ^[5][6]. Because their natural drainage system is not completely mature, simply creating a bypass with an ETV is sometimes not enough to relieve the pressure ^[1].

What is CPC and How Does it Help?

To help the infant’s immature absorption system, neurosurgeons may add CPC. The choroid plexus is a network of blood vessels and cells inside the brain’s ventricles that acts as the primary source of cerebrospinal fluid ^[2].

During CPC, the surgeon uses the same endoscope (a tiny camera tool) used for the ETV to locate this tissue. They use a small electrical current to cautiously cauterize (burn) safely accessible portions of the choroid plexus ^[2].

• Lowering the Volume: Deactivating this tissue means the brain produces less fluid overall, although it does not stop production completely ^[2].
• Lessening the Burden: Surgeons treat as much of the tissue as they safely can, but the exact amount varies depending on the baby’s anatomy ^[7]. The goal is to lower the daily fluid burden enough so the baby’s developing absorption pathways aren’t overwhelmed ^[8].

Success Rates and What They Mean

The goal of combining ETV and CPC is to achieve “shunt independence”—managing the hydrocephalus without needing to implant a permanent mechanical tube (shunt) ^[3].

For infants specifically dealing with aqueductal stenosis, combined studies have shown a pooled success rate of approximately 71% ^[9]. However, this is a population average based on specific study follow-ups, not a guarantee for an individual child. Overall success across all infants with various causes of hydrocephalus is closer to 59%, and outcomes can vary widely depending on the hospital and the baby’s specific condition ^[9][10].

Age is one important factor. Outcomes tend to improve as infants get slightly older (for example, babies older than 1 to 2.5 months often have better success rates) because their absorption systems have had more time to mature ^[11][12]. However, there is no magical age cutoff; a surgeon will also consider the cause of the hydrocephalus, the baby’s anatomy, and whether they have had prior brain bleeding or infections ^[11].

Understanding the Risks

While ETV/CPC aims to avoid a shunt, it is a major brain surgery with its own risks. Possible complications include bleeding, infection, leakage of CSF fluid, and injury to nearby vital brain structures or blood vessels ^[10]. There are also hormonal (endocrine) risks due to the surgery’s location. Furthermore, an open ETV pathway can sometimes close or fail months or even years later, meaning the child might still require a shunt in the future ^[13]. (It is worth noting that shunts also carry significant risks, such as mechanical failure and infection, which is why ETV/CPC is often considered first).

Warning Signs of ETV/CPC Failure

If the ETV pathway closes or the fluid production remains too high, pressure will build up again. It is critical to monitor your infant closely at home. Contact your neurosurgical team urgently or seek emergency care if you notice:

• A tense or bulging fontanelle (the soft spot on the baby’s skull) when the baby is calm and upright
• Rapidly increasing head size
• Repeated vomiting or severe poor feeding
• Unusual sleepiness or extreme difficulty waking the baby up
• Abnormal eye movements (like eyes persistently looking downward, often called “sunsetting”)
• Seizures
• Fever, or redness and drainage at the surgical incision site

Post-Surgery Follow-Up

Follow-up is not just about getting a reassuring MRI scan. While imaging (like MRI flow studies) helps visualize if the ETV pathway is open, it does not guarantee the pressure is adequately controlled ^[14]. Your medical team will heavily rely on clinical signs: measuring your baby’s head growth, assessing their development, and checking their fontanelle.