Gamma Knife radiosurgery for spontaneous carotid-cavernous fistulas: a preliminary report

Abstract

Objective: Gamma Knife radiosurgery (GKRS) is used as an adjuvant treatment for carotid-cavernous fistulas (CCFs), and many previous reports have concluded that GKRS is a useful additional modality. We performed GKRS on CCFs without any endovascular treatment and present the preliminary results.Methods: Between December 2017 and December 2020, we performed GKRS in nine patients. Seven patients were female, and two patients were male (median age, 73 years; range, 46 to 86 years). Five fistulas were Barrow type B (one patient had bilateral CCF). Four fistulas were type C. One was type D. GKRS was performed with a marginal dose of 16 to 18 Gy (median, 17.5 Gy; 50% isodose line), and the mean targeted volume was 0.39 cm3 (range, 0.13 to 3.05 cm3). Results: All fistulas responded favorably to GKRS, with symptom improvement after 1 to 32 weeks (median, 3 weeks). The median follow-up period was 15.5 months (range, 12 to 43 months). Seven fistulas disappeared following treatment, which was confirmed by transfemoral angiography or orbit magnetic resonance imaging and brain magnetic resonance angiography (MRA). Three fistulas in the diameter of the superior ophthalmic vein decreased by more than 50%, as indicated by MRA. There were no cases of recurrence or adverse effects.Conclusion: Although further research requires a larger patient group and longer follow-up duration, GKRS can be considered a definitive treatment modality for any type of CCF, not only an adjuvant modality.