Objective and importance: Treatment of tentorial dural arteriovenous fistulae (DAVFs) primarily draining into the vein of Galen remains a therapeutic challenge. We present two cases of ruptured galenic DAVFs that were successfully treated with gamma knife radiosurgery.
Clinical presentation: Patient 1, a 66-year-old woman, experienced a sudden onset of headache and loss of consciousness. Neuroimaging studies revealed intraventricular hemorrhage and a DAVF with aneurysmal dilation of the vein of Galen. The DAVF was supplied by tentorial branches of the right meningohypophyseal artery and bilateral supracerebellar arteries, which drained directly into the vein of Galen. Patient 2, a 64-year-old woman, experienced subarachnoid hemorrhage. Cerebral angiography revealed a galenic DAVF at the falcotentorial junction, which was supplied by bilateral supracerebellar arteries. This patient had an aneurysm at the origin of the left supracerebellar artery.
Intervention: Both patients were treated with gamma knife radiosurgery. In each case, the fistula was exclusively targeted and a dose of more than 20 Gy was delivered. Complete obliteration of the fistula was confirmed 27 and 29 months after radiosurgery for Patients 1 and 2, respectively, whereas the normal venous structures of the galenic system were preserved.
Conclusion: Gamma knife radiosurgery is an effective treatment modality for DAVFs primarily draining into the vein of Galen. Irradiation doses of more than 20 Gy, strictly limited to the fistulae, seem to be sufficient for successful obliteration of these high-risk vascular lesions, with minimal invasiveness.