Objective: To evaluate the efficacy of embolization for spinal dural arteriovenous fistulae (SDAVF).
Methods: We reviewed 49 cases of SDAVF treated by embolization. An acrylic material was used in all except two cases. Variable stiffness microcatheters were used in 38 cases.
Results: "Adequate" initial treatment was performed in 39 cases (80%). After the introduction of variable stiffness microcatheters, the initial success rate of embolization increased to 87% (33 of 38 cases). Eight patients underwent subsequent embolization for recurrence after "adequate" embolization. Causes of recurrence were collateralization in five cases, development of new fistulae in one, and unknown in two. Two additional patients developed subsequent aggravation of the symptoms, probably caused by progressive venous thrombosis, that responded to heparinization. Ten cases were initially "inadequately" embolized. Five of the 10 cases were treated before the introduction of variable stiffness microcatheters. Each of three of the remaining five cases had a common trunk from which the feeder and a spinal cord artery arose.
Conclusion: Embolization with an acrylic material should be the first choice of treatment for SDAVF, unless a spinal cord artery shares the same pedicle as the feeder of SDAVF. Subsequent aggravation of the symptoms after embolization can occur by various mechanisms. Therefore, periodic and long-term follow-up examinations are important.