Object. The aim of this study was to assess whether glue-induced occlusion of the draining vein predicts permanent closure of the fistula following embolization of spinal dural arteriovenous fistulas (SDAVFs). Methods. Between 1994 and 2004, 36 consecutive patients with an SDAVF were treated at the authors' institution. Twelve patients underwent surgery and 24 glue-based embolization. In 12 of 24 embolization procedures the draining vein was occluded and no recurrence or persistent fistula was seen during the follow-up period. In the other 12 patients the glue had not reached the draining vein and in eight of these the fistula recurred, necessitating additional treatment. Conclusions. In embolization of SDAVFs penetration of the glue into the draining vein predicts permanent closure of the fistula. When penetration of the glue into the draining vein can be expected, embolization is the preferred treatment option. In other cases surgery should be the treatment of choice.