OBJECTIVE: To evaluate the efficacy of embolization for spinal dural a
rteriovenous fistulae (SDAVF). METHODS: We reviewed 49 cases of SDAVF
treated by embolization. An acrylic material was used in all except tw
o cases. Variable stiffness microcatheters were used in 38 cases. RESU
LTS: ''Adequate'' initial treatment was performed in 39 cases (80%). A
fter the introduction of variable stiffness microcatheters, the initia
l success rate of embolization increased to 87% (33 of 38 cases). Eigh
t patients underwent subsequent embolization for recurrence after ''ad
equate'' embolization. Causes of recurrence were collateralization in
five cases, development of new fistulae in one, and unknown in two. Tw
o additional patients developed subsequent aggravation of the symptoms
, probably caused by progressive venous thrombosis, that responded to
heparinization. Ten cases were initially ''inadequately'' embolized. F
ive of the 10 cases were treated before the introduction of variable s
tiffness 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 sym
ptoms after embolization can occur by various mechanisms. Therefore, p
eriodic and long-term follow-up examinations are important.