Deterioration after surgical treatment of spinal dural arteriovenous fistula associated with spinal perimedullary fistula.

Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of vascular malformations of the spine and are defined as abnormal arteriovenous shunts within the dura. SDAVFs are considered to be acquired and should be distinguished from congenital intradural perimedullary arteriovenous fistulas (PMAVFs). A 32-year-old female presented with both SDAVF and PMAVF, manifesting as a slowly progressive paraparesis over a 6-month period. Initial spinal angiography demonstrated an SDAVF in the sacral region and was terminated with incomplete demonstration of all segmental arteries. The fistula was obliterated by surgery and the patient showed transient postoperative improvement followed by delayed deterioration 2 months later. Magnetic resonance (MR) imaging showed many hypointense flow voids around the cord. The second angiography verified a PMAVF in the lumbar region and complete obliteration of the SDAVF. The fistula was closed by surgery and the patient improved slightly. Surgical results of SDAVFs are generally good. Therefore, if a patient fails to improve or deteriorates further after surgery with persistent perimedullary vessel abnormalities on MR imaging, the possibility of reopening of the fistula or the presence of another fistula should be considered and repeat angiography must be performed, especially if the initial angiography was incomplete.