THE ROLE OF CT IN EVALUATION OF THE EFFECTIVENESS OF EMBOLIZATION OF SPINAL DURAL ARTERIOVENOUS-FISTULAS WITH N-BUTYL CYANOACRYLATE

A failed embolisation of a spinal dural arteriovenous fistula (AVF), b ecause a pedicular injection has not reached the initial venous compar tment, must be identified immediately, to allow prompt surgery and thu s avoid clinical deterioration. The purpose of our study was to determ ine the role of CT in confirming a complete cure just after embolisati on with N-butyl cyanoacrylate (NBCA). Seven patients embolised for spi nal dural AVFs with perimedullary venous drainage had an immediate pos tembolisation CT scan. In six patients a complete cure was achieved, w ith a normal postembolisation angiogram in five cases. Just after inje ction of NBCA, we were unable to determine on plain films whether or n ot the glue had reached the draining vein in six of seven cases. The p ostembolisation CT showed various patterns: in two cured patients, the glue was visible in the inner surface of the dura mater and therefore on the venous side. In five cases, the glue was approaching the dura mater around the cord or seemed to reach its surface: in the four pati ents cured, the glue column was 7-18 mm high, whereas it was less than 2 mm high in the patient with angiographic proof of recurrent fistula . The follow-up angiogram remains the only way to confirm a durable cu re. We suggest that immediate postembolisation CT may help in assessin g endovascular treatment of spinal dural AVFs.