Exclusively Epidural Spinal Arteriovenous Malformation: A Short ReviewAuthor(s): Hai-Feng Wang, Da-Ming Wang
The incidence of exclusively epidural spinal arteriovenous malformation (EESAVM) is extremely low and there are only a few case-reports in literature. Early, correct recognition of the pathology is mandatory to halt the progression of the disease and minimize permanent spinal cord injury. This review depicts EESAVM’s characteristics, from the aspect of pathophysiology, clinical presentation, treatment strategies, and outcome. EESAVMs are located entirely in the epidural space and fed by radicular vessels or segmental arteries. The nidus of EESAVM purely locates in the spinal epidural space. The drainage of nidus flows into the epidural venous plexus or intradural vein. The retrograde blood flow from the AVM results in a diminished intramedullary blood flow and symptoms due to spinal cord ischemia and myelopathy. There is no gender predilection (male 52.9%), age distribution by the time of diagnosis shows most cases are younger than 20-year (64.7%), most cases present as spontaneous epidural hematoma (64.7%), and the majority of those lesions are located on cervicothoracic junction or upper thoracic segment (75%). Generally, the clinical presentation of EESAVM is slighter than intradural/intramedullary AVMs. Unruptured EESAVM may symptomless, or present as protracted, progressive neurological decline. Ruptured EESAVM may present acute back or thoracic pain subsequently with paraplegia. Epidural haemorrhage is common and urgent condition for EESAVM. Up to now, spinal angiography remains the gold standard and the first choice for diagnosis and characterization of spinal vascular lesion. The best management for EESAVM is still surgical operation. Prompt diagnosis and emergency surgical treatment are crucial. Long-term functional prognosis of EESAVM is good, but delayed surgical operation
leave residual symptoms.