The Endoscopic Third Ventriculostomy Success Score (ETVSS), developed by Kulkarni et al. at SickKids Toronto and validated by the Hydrocephalus Clinical Research Network (HCRN), predicts the probability of ETV success at 6 months without requiring repeat CSF diversion or shunt conversion.
Because an ETV frees a child from a lifetime of hardware dependency, mechanical blockages, and shunt infections, offering an ETV when there is a reasonable prospect of success is standard pediatric neurosurgical practice.
ETV Success Score (ETVSS) Stratification
| Category | Clinical Variable | Sub-Score |
|---|---|---|
| Age | < 1 month | 0 |
| 1 month to < 6 months | 10 | |
| 6 months to < 1 year | 20 | |
| 1 year to < 10 years | 30 | |
| \ge 10 years | 40 | |
| Etiology | Post-infectious | 0 |
| Myelomeningocele / Spina bifida | 20 | |
| Intraventricular hemorrhage (IVH) / Post-hemorrhagic | 20 | |
| Other (e.g., Dandy-Walker, trauma) | 20 | |
| Tectal / Pineal / Brainstem tumor | 30 | |
| Aqueductal stenosis | 30 | |
| Previous Shunt | Previous shunt present | 0 |
| No previous shunt | 10 |
Clinical Interpretation & Decision Tiers
- Low Chance (\le 40%): ETV alone has a high failure rate. In neonates with post-infectious or post-hemorrhagic hydrocephalus, subarachnoid cisterns and arachnoid granulations are frequently scarred or obliterated. If an endoscopic approach is pursued in this tier, pairing ETV with Choroid Plexus Cauterization (CPC) substantially improves outcomes over ETV alone.
- Moderate Chance (50% – 70%): Clinical gray zone where pathology, anatomical factors, and parental preference dictate management. The majority of infants older than 6 months with myelomeningocele or non-communicating lesions sit in this cohort.
- High Chance (\ge 80%): Clear candidate for ETV (e.g., older children with pure aqueductal stenosis or tectal gliomas). Ventriculoperitoneal (VP) shunting is generally reserved only as a fallback.
Key Pre-Operative Anatomical Considerations Beyond ETVSS
While the ETVSS provides a statistical baseline, surgical feasibility is dictated by high-resolution neuro-imaging (thin-slice 3D T2/CISS/FIESTA MRI):
Third Ventricular Anatomy
- Size of the Foramen of Monro: Must accommodate the rigid or flexible neuroendoscope without causing fornix contusion.
- Floor Attenuation & Distortion: A thinned, translucent tuber cinereum is optimal. An opaque, thick floor (often after severe ventriculitis) makes target visualization hazardous.
Basilar Artery Position
- Safe fenestration occurs strictly in the midline, anterior to the basilar tip and posterior to the clivus/infundibular recess. A high-riding basilar tip abutting the floor elevates the risk of vascular catastrophe.
Prepontine Cistern Patency
- Lilliquist’s membrane must be identified and widely opened in addition to the ventricular floor itself to ensure free communication with the prepontine, interpeduncular, and premedullary cisterns. Scarred or fibrosed basal cisterns prevent CSF reabsorption, causing early stoma failure.
This page is for general education only and does not replace an in-person consultation. If your child shows sudden changes — seizures, persistent vomiting, drowsiness or wound leakage — go to the nearest emergency department immediately.