Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal vascular malformations. However, SDAVFs are still underdiagnosed entities because their clinical symptoms are usually non-specific, as they include low back pain or radiating pain to the limb. There have been several reports of acute paraplegia after lumbar epidural steroid injections in patients with SDAVFs. We present 4 patients with SDAVFs who received lumbar steroid injection. Among the 4 cases, acute paraplegia developed in 2 cases that received a larger volume of injectate than the other cases. Thus, we are suggesting that the volume of injectate may be a contributing factor for acute paraplegia after lumbar steroid injection in patients with SDAVFs.