Arterio-venous malformations occur mainly intradurally and are rarely found extradurally. We report a case of an extradural arterio-venous malformation with sciatic nerve pain.
A 41-year-old man complained of right buttock pain and right foot hypesthesia. Neurological findings suggested right L5 nerve-root irritation and myelogram and CT myelogram revealed a defect of the right L5 nerve-root. There were no abnormal findings in the discogram at the L4/5 Level, and the coronal MRI view at the L4/5 level showed a tumor shadow enhanced by gadolinium. We therefore suspected an extradural tumor and tried to resect it. At surgery, there was a darkpurple colored tumor on the lateral side of the right L5 nerve-root but it bled arterially, so we closed the wound because of the suspicion of vascular disorder and the potential risks associated with continuing the operation. After surgery, we performed selective angiography which showed a fungusball like tumor shadow near the right L5 nerve-root. We performed transcatheter embolization and resected again with the resected tumor proving to be an arterio-venous malformation pathologically.
Extradural arterio-venous malformations occupy only 0.88% of all spinal tumors of the Pia and only 2 cases have been reported in Japan.
