Update on the Diagnosis and Treatment of Arteriovenous Fistulas at the Craniocervical Junction: A Systematic Review of 92 Cases

Objective: The purpose of this study was to provide an update on recent developments in the diagnosis and treatment of arteriovenous fistulas at the craniocervical junction (CCJ AVFs). Methods: Associated literature published between 2009 and 2018 on the PubMed database was reviewed. Results: The systematic review identified 97 lesions in 92 cases of CCJ AVFs. These lesions were divided into three groups according to their angioarchitecture: 56 lesions of dural AVFs, 34 of intradural AVFs, and 7 of extradural AVFs. Clinical features, neuroimaging findings, treatments, and outcomes were compared among the three groups. Cases of dural AVFs were commonly associated with myelopathy and/or brainstem dysfunction due to venous congestion in the spinal cord (38%) and/or brainstem (21%). Cases of intradural AVFs had a more complex angioarchitecture than those of dural AVFs and were associated with a hemorrhagic presentation (83%). Of the 34 intradural AVFs, 25 lesions (74%) had a feeder aneurysm (n = 20) or varix (n = 5). The development of the aneurysm/varix may be attributed to hemodynamic and flow-related phenomena. The surgical obliteration of the intradural drainer and/or feeder was effective in most cases of dural and intradural AVFs. Endovascular embolization may be more effective in cases of extradural AVFs than in those of dural or intradural AVFs. No permanent neurologic complications occurred in 80 cases treated by surgery; however, brain infarction occurred in 2 (9%) of 22 cases treated by endovascular embolization. Good recovery was more frequently achieved in cases of intradural (79%) and extradural AVFs (100%) than in those of dural AVFs (61%) because cases with hemorrhagic presentation had fewer permanent neurologic deficits than those with venous congestion. Conclusion: A differential diagnosis among dural, intradural, and extradural AVFs is important because clinical features, neuroimaging findings, and treatment outcomes markedly differ among the three groups.