Conus perimedullary arteriovenous fistula with intracranial drainage: Case report

OBJECTIVE AND IMPORTANCE: Perimedullary arteriovenous fistulae (AVFs) do not commonly present with subarachnoid hemorrhage or intracranial venous drainage causing neurological symptoms. We present a case with both of these features. The patient was inadvertently treated for an unruptured intracranial aneurysm before his true problem was recognized. CLINICAL PRESENTATION: A 65-year-old man presented with sudden-onset lower-extremity weakness, diplopia, nausea, and dysarthria on the day of admission. A lumbar puncture documented subarachnoid hemorrhage, and imaging studies revealed a left middle cerebral artery aneurysm. It was noted during surgery that this aneurysm was unruptured, and the patient did not exhibit improvement after surgery. INTERVENTION: Spinal angiography demonstrated a spinal perimedullary AVF feeding from the left T12 radicular artery; venous drainage extended rostrally into the posterior fossa venous system. The AVF was surgically occluded via a posterior laminectomy at the level of the AVF. After surgery, the patient's symptoms began to abate. CONCLUSION: Conus perimedullary AVFs can have venous drainage that extends as far as intracranial veins, which can lead to confusing clinical findings because the symptoms may suggest an intracranial process, although the lesion is in the spine. Surgeons must be aware of this confusing presentation.