Background Idiopathic Intracranial Hypertension (IIH) is characterized by elevated intracranial pressure, papilledema, and often transverse sinus stenosis, in the absence of imaging or cerebrospinal fluid (CSF) abnormalities. Current treatments focus primarily on medical management, weight loss, and dural venous sinus stenting. However, inspired by arachnoid granulation function, a novel endovascular device may show significant potential in improving IIH management. The eShunt System is a transdural shunt deployed via the inferior petrosal sinus (IPS) to drain CSF from the cerebellopontine angle cistern (CPAC) into the internal jugular vein. Although it has shown promising results in patients with normal pressure hydrocephalus, the implant’s applicability in IIH remains undefined. This study aims to characterize the morphometrics of cisternal, venous, and skull base anatomy in adult patients with IIH-associated dural venous sinus stenosis and evaluate them against minimum required dimensions for safe deployment of the eShunt implant.

Methods High-resolution T1-weighted Gadolinium-enhanced brain MRIs of IIH patients post-venous sinus stenting at Tufts Medical Center (Boston, MA) were retrospectively analyzed to measure CPAC depth, IPS diameter, IPS angle, and cerebellar tonsillar descent; pertinent history and demographics were also assessed.

Results Sixty adult patients (ages 18-77, 50 females) were included. Median CPAC depth was 4.5 mm and 4.4 mm, while median IPS diameter was 4.1 mm and 3.8 mm, for right and left sides, respectively. CPAC depth trended higher in older (P=0.05) and male (P=0.07) patients, but not significantly. Transverse sinus stenting did not significantly affect cistern dimensions (P=0.8). Endovascular placement of the eShunt implant was possible with stringent (CPAC depth >5mm and IPS diameter >2mm), moderate (CPAC depth >4mm and IPS diameter >2mm), and permissive (CPAC depth >3mm and IPS diameter >2mm) feasibility criteria in 55%, 65%, and 78% of analyzed patients, respectively. Interestingly, CPAC depth was found to be inversely correlated with cerebellar tonsillar descent (P<0.01); patients with Chiari I diagnoses tended to have small CPA cisterns. On excluding 26 patients with tonsillar descent below the foramen magnum, eShunt eligibility rose to 62%, 76%, and 91%, under stringent, moderate, and permissive criteria, respectively. Thus, cerebellar tonsillar position emerges as another predictive factor for eShunt eligibility.

Conclusion A significant proportion of patients with IIH currently treated with dural venous stenting may be suitable candidates for the eShunt implant. Its biomechanical potential for ICP reduction, minimally invasive endovascular deployment, and lack of anti-coagulant and anti-platelet requirements, warrant further clinical investigation of its role in IIH management.