Classification and surgical management of spinal arteriovenous lesions: arteriovenous fistulae and arteriovenous malformations.

OBJECTIVE: Preexisting spinal arteriovenous malformation nomenclature can be confusing. The aim of this article is to present a modified classification system for spinal arteriovenous lesions and to discuss its implications for microsurgical strategies.
METHODS: Based on the literature review of prior classifications as well as on the experience of the senior author (RFS), the authors delineate an anatomically and pathophysiologically based classification to facilitate the description and treatment of these uncommon entities.
RESULTS: Spinal arteriovenous lesions are composed of arteriovenous fistulae and malformations. These lesions are classified as extradural, extradural-intradural, or intradural. Intradural lesions are characterized further as ventral or dorsal fistulae or as intramedullary lesions. Intramedullary lesions are characterized as compact or diffuse. A new category, conus medullaris arteriovenous malformations, is described as a distinct entity.
CONCLUSION: This updated classification system eliminates confusion related to older nomenclature and is based on the anatomical and pathophysiological features of these lesions. When treating these lesions, the neurovascular team must collaborate closely with their microsurgical and endovascular colleagues. Finally, treatment should be individualized, depending on lesional angioarchitecture and the patient's clinical status.