Spinal dural arteriovenous fistula masquerading as subdural hematoma

Background: This case highlights an angiographically occult spinal dural AVF presenting with a spinal subdural hematoma. While rare, it is important that clinicians be aware of this potential etiology of subdural hematomas before evacuation. Case Description: A 79-year-old female presented with acute lumbar pain, paraparesis, and a T10 sensory level loss. The MRI showed lower cord displacement due to curvilinear/triangular enhancement along the right side of the canal at the T12-L1 level. The lumbar MRA, craniospinal CTA, and multivessel spinal angiogram were unremarkable. A decompressive exploratory laminectomy revealed a subdural hematoma that contained blood products of different ages, and a large arterialized vein exiting near the right L1 nerve root sheath. The fistula was coagulated and sectioned. Postoperatively, the patient regained normal function. Conclusion: Symptomatic subdural thoracolumbar hemorrhages from SDAVF are very rare. Here, we report a patient with an acute paraparesis and T10 sensory level attributed to an SDAVF and subdural hematoma. Despite negative diagnostic studies, even including spinal angiography, the patient underwent surgical intervention and successful occlusion of the SDAVF.