Morphometric analysis of the inferior petrosal sinus and cerebellopontine angle cistern to assess feasibility of endovascular shunting in pediatric patients

Background: Hydrocephalus is commonly treated using invasive surgical shunt placement with associated morbidity and frequent revision in children. The eShunt System, an endovascular miniature transdural shunt implanted via the inferior petrosal sinus (IPS), has shown promise in adults, but its pediatric application remains undefined because of limited data on IPS and cerebellopontine angle cistern (CPAC) morphometry. Materials and methods: Consecutive patients from two pediatric hospitals with high-resolution brain MRI were retrospectively analyzed. IPS and CPAC measurements were evaluated against adult anatomical criteria for safe implantation (IPS size ≥2 mm, IPS angle <150, and ≥5 mm distance from the dural access point to the brainstem or major artery). Regression analyses assessed the relationship between age and IPS/CPAC measurements. Results: One hundred patients were included: 20 toddlers (1-2 years), 24 preschool age (3-5), 27 school age (6-11), and 29 adolescents (12-18). Median IPS size was 2.8 mm (2.4-3.3 mm) and 2.8 (2.5-3.4 mm) while median CPAC depth was 7.6 mm (5.6-9.0 mm) and 6.8 mm (5.5-8.5 mm) for the right and left side, respectively. While younger age was associated with smaller IPS diameter (P<0.001 for both), the correlation was weak (R² = 13.9% and 13.5% for right and left, respectively). Age was not associated with differences in other metrics after multivariable adjustments. Endovascular shunt placement was deemed feasible based on adult criteria in 67% of patients, with no age-based differences in eligibility (P=0.57). Conclusion: A majority of patients over 1 year of age met IPS and CPA anatomical criteria for placement of the eShunt System.