The aim of the present study is to better understand the histological alterations of arterialized medullary veins (MV) in spinal dural arteriovenous fistulas (SDAVFs) and its relationship to clinical status before and after surgical treatment of SDAVFs. Three patients presented with progressive congestive myelopathy of varying duration. In all three cases, magnetic resonance imaging (MRI) demonstrated patchy cord enhancement on postcontrast Tl-weighted images, and extension of spinal intramedullary high signal on T2-weighted images. Spinal angiography demonstrated SDAVFs with retrograde filling of the medullary vein (MV). Surgical obliteration was achieved by direct intradural interruption of the arterialized MV in all cases. After surgical interruption, a segment of the arterialized MV was obtained from each patient for histological examination. The three patients were stabilized or improved neurologically after surgery, with a gradual decrease of spinal intramedullary high signal on T2-weighted MR images. Histological examination showed hyperplasia of the elastic fibers of the MV, which varied between the three cases. These histological alterations of the MV appeared to reflect the preoperative evolution of retrograde venous hypertension of the spinal cord circulation, and may correlate with neurological recovery. The histological alterations of the spinal cord circulation in cases of SDAVF may reflect the progressive and irreversible nature of spinal cord function. Although the relationship between the spinal cord circulation and function needs to be further explored, better understanding of the histological nature of SDAVFs is important for their early and appropriate treatment.
