What Makes a Baby a Candidate for ETV Surgery?

Making decisions about your newborn’s first brain surgery is incredibly overwhelming. When a baby is diagnosed with congenital hydrocephalus, neurosurgeons must decide between a standard ventriculoperitoneal (VP) shunt (a flexible tube placed under the skin that drains excess spinal fluid from the brain to the abdomen) and an endoscopic third ventriculostomy (ETV) (a procedure that creates a natural fluid bypass within the brain itself).

To determine if a baby is a good candidate for an ETV, doctors primarily look at three clinical factors—the baby’s age, the specific cause of the hydrocephalus, and whether they have had a previous shunt ^[1]. They also closely examine the baby’s MRI to see the shape of the brain’s ventricles and the space around the brainstem ^[2]. The goal is to predict if creating a natural bypass will successfully drain the spinal fluid, allowing the child to avoid a lifelong implanted device ^[3].

The ETV Success Score (ETVSS)

To help make this decision, neurosurgeons use a tool called the ETV Success Score (ETVSS) ^[4]. This scoring system calculates the likelihood that an ETV will work based on a percentage. Higher scores are generally considered more favorable. The score focuses on three main factors ^[1]:

• The Baby’s Age: Age is a major factor in ETV success. Babies under 6 months old naturally have a lower success rate with ETV surgery than older infants and children ^[5]. Because their brains are still developing and absorbing fluid differently, the newly created opening can sometimes close up or fail to manage the fluid.
• The Cause (Etiology): The specific reason for the hydrocephalus matters greatly ^[6]. ETV works best for obstructive hydrocephalus, where there is a physical blockage. Babies with aqueductal stenosis (a narrowing of the channel between the brain’s fluid spaces) are considered ideal candidates and generally have higher success scores ^[7]. Babies whose hydrocephalus was caused by bleeding (hemorrhage) or infection often have lower scores because those conditions can affect how well the brain absorbs fluid overall.
• Previous Shunt History: A baby who has never had a shunt placed generally has a slightly better chance of a successful ETV compared to a child who already has a failing VP shunt ^[1].

Anatomical Signs on the MRI

Beyond the ETVSS, neurosurgeons carefully study the child’s MRI for specific physical features that suggest an ETV will work well.

• Bowing of the Third Ventricle Floor: If the MRI shows that the floor of the third ventricle (a fluid-filled space deep in the brain) is bowing or pushing downward, this is a very strong sign that an ETV will be successful ^[2][8]. It indicates that the fluid pressure is high and localized, meaning a small hole in that floor will successfully relieve the pressure.
• The Prepontine Cistern: This is the fluid space just below the third ventricle where the fluid will drain after the ETV is performed. The surgeon needs to ensure this space is open and free of thick membranes or scarring ^[9]. If the prepontine space is restricted, the fluid won’t be able to flow out properly, increasing the chance of failure.

ETV Combined with CPC

For babies under 1 year old (who naturally have a lower ETVSS score), neurosurgeons will often combine the ETV with a second procedure called choroid plexus cauterization (CPC) ^[10]. The choroid plexus is the tissue inside the brain that produces spinal fluid. By using a specialized instrument to apply heat (cauterize) to some of this tissue, fluid production is reduced. Adding CPC has been shown to significantly boost the success rate of ETV in young infants, turning many babies who would have needed a VP shunt into good candidates for the combined ETV/CPC procedure ^[11][12].

Balancing Surgical Risks and Long-Term Benefits

Both procedures carry unique risks. While a VP shunt is highly reliable right away, it leaves a child dependent on a medical device that carries lifelong risks of mechanical failure and infection ^[3]. An ETV avoids these long-term device risks but carries immediate surgical risks, such as spinal fluid leakage, postoperative fever, and very rarely, injury to surrounding blood vessels ^[13][14].

An ETV also has a higher risk of failing in the first few months after surgery compared to a shunt, especially in very young babies ^[15]. “Failure” simply means the new opening has closed or isn’t draining enough fluid, which causes hydrocephalus symptoms to return (such as a bulging soft spot, vomiting, or extreme fussiness). If an ETV fails, a VP shunt can safely be placed as a standard fallback option. Knowing there is a reliable backup plan can offer peace of mind as you and your neurosurgeon weigh all these factors to find the safest, most effective path forward for your baby ^[16].