Endoscopic Third Ventriculostomy with Possible Cauterization is Safe and Effective for Treatment of Hydrocephalus in Previously Embolized Vein of Galen Malformations.

Introduction: Vein of Galen Malformations (VOGM) are arteriovenous malformations in young children and neonates. Patients can present with communicating hydrocephalus due to underlying venous hypertension. Rarely, patients present with obstructive hydrocephalus due to direct mass effect of the malformation on the cerebral aqueduct. Given the limited literature in management of embolized VOGM patients with persistent hydrocephalus, we evaluate the safety and efficacy of endoscopic third ventriculostomy (ETV) in this patient population.

Methods: We conducted a single institution retrospective review of all VOGM patients who presented with worsening hydrocephalus despite treated malformation via embolization and underwent ETV from 2022 - 2023.

Results: 4 patients met inclusion criteria. Average age at the time of ETV was 5 months (2-11 months). Two patients (50%) had obstruction of the aqueduct on preoperative imaging. All patients underwent prior endovascular embolization, average number of embolizations 2.75 (range 2 to 5 embolizations) with no further targetable sites and minimal flow within the malformation at final embolization. All patients had evidence of worsening hydrocephalus based on preoperative FOHR trends (average 0.63 +- st.dev 0.07) and Evans' Index (0.62 +- 0.1). One patient underwent cauterization at time of ETV without adverse events. There were no complications after ETV, with an average of 5% (1.5%-15%) reduction in FOHR at the most recent followup, average 2.6 months after ETV (0-7.7 months). Our ETV success rate is 75%. One patient with minimal reduction (1.5%) in FOHR is under consideration for permanent CSF diversion.

Conclusion : We demonstrate safety and efficacy of ETV in VOGM patients, with improvement in hydrocephalus in the majority of patients and no adverse complications. ETV with or without cauterization can offer a minimally invasive treatment for hydrocephalus in these cases, as well as treatment of the smaller feeders not embolized with endovascular methods.