Spinal arteriovenous fistula. A possible cause of paraparesis after epidural anaesthesia.

A 62-year-old male suddenly developed a severe paraparesis after epidural anaesthesia. He recovered gradually over the next few months. He had an acute relapse one year later and a selective spinal angiography showed a dural T8 arteriovenous fistula with large draining veins. Intravascular embolisation of the fistula produced immediate and sustained clinical improvement. The mechanism commonly held responsible for neurological disturbances in spinal dural arteriovenous fistulas is cord hypoxia secondary to venous hypertension. The 20-ml of local anaesthetic solution injected into a narrow spinal canal with osteophytosis may have caused further venous engorgement, cord hypoxia and acute neurological deficit.