Lumbar Epidural Arteriovenous Fistulas: A Systematic Review of the Literature

Introduction: Spinal dural arteriovenous fistulas (SDAVFs) are the most common vascular malformation of the spine and are associated with a much rarer subtype, spinal epidural arteriovenous fistulas (SEDAVFs). These epidural counterparts feature an abnormal vasculature connection between the spinal epidural arterial system and the epidural venous plexus compared to the dural involvement at the nerve root in SDAVFs. Making this distinction is vital as it impacts treatment, with the epidural component resulting in better outcomes with endovascular embolization compared to open surgery with the more traditional SDAVFs. By understanding the different types of vascular malformations in the spine, neurosurgeons are better informed to make appropriate treatment decisions to improve patient outcomes. A literature review was performed to better delineate the distinction between these two phenomena as SEDAVFs are commonly misdiagnosed as SDAVFs.

Methods: A systematic review was conducted according to PRIMSA, utilizing PubMed, Scopus, and Embase from database inception through October 30th, 2024. Searchable keywords included “epidural fistula,” “dural arteriovenous fistula,” and “lumbar.” Two reviewers helped to screen the abstracts utilizing COVIDENCE tool. Articles were excluded if they were review articles, editorials, conference presentations, or if they lacked sufficient clinical data.

Results: 399 articles remained after the initial search which included 720 articles. 173 of these were sought for full text review and 13 articles were finalized for data interpretation and collection. These documents were read and summarized to provide an updated perspective on SEDAVFs.

Conclusion : SEDAVFs are a rare vascular phenomenon which may be commonly misdiagnosed. Out of the 149 patients analyzed in this literature review, diagnosis is typically seen in older man and may be associated with prior surgery or degenerative changes to the spine, with lumbosacral components being most common. Patients tend to improve significantly with endovascular intervention though microsurgical techniques are also plausible.