Dural Arteriovenous Fistulas of the Craniocervical Junction: Anatomical Considerations, Clinical Presentation, and Microsurgical Management

Background Dural arteriovenous fistulas (DAVFs) of the craniocervical junction (CCJ) represent very rare arteriovenous shunts between dural arteries and veins of this area. The classification of these fistulas is based on the draining vein or sinus. Hypoglossal canal, jugular foramen, posterior condylar vein, and marginal sinus fistulas are the commonest types. The clinical presentation of the patients with DAVFs of the CCJ depends on their venous drainage pattern, and thus, the detailed knowledge of the complex venous anatomy and its variations of the CCJ is very important in understanding the pathophysiology, interpreting the clinical symptomatology and establishing their treatment plan. Microsurgical disconnection of the fistulas site using skull base approaches remains a very important consideration for the treatment of these pathologies.

Objective The purpose of this study is to present two representative cases of DAVFs of the CCJ, analyzing their angiographic characteristics and their clinical symptomatology and discussing the most appropriate treatment plan.

Methods Case 1: A 72-year-old man presented with right side intramedullary hemorrhage resulted in lower cranial nerve dysfunction. Six vessels angiogram revealed a right side DAVF supplied by right C1 and C3, branches, right ascending pharyngeal artery, and right occipital artery and draining to prepontine vein and superior petrosal sinus. The patient underwent two cycles of arterial embolization with total obliteration of the shunt and his cranial nerve function complete recovered. The follow-up angiogram 8 months later revealed recanalization of the DAVF. Right far lateral craniotomy was performed and disconnection of the DAVF was achieved. Early postoperative angiogram confirmed complete disconnection of the shunt. Case 2: A 39-year-old woman presented with HH4 subarachnoid hemorrhage with blood localization around the foramen magnum and inside the fourth ventricle. The angiography revealed a left perimedullary DAVF feed by a branch of the left vertebral artery and draining to a premedullary pial vein. The patient underwent a left far lateral craniotomy and disconnection of the fistula. Intraoperative angiography revealed no residual shunt. Postoperatively the clinical examination of the patient improved and returned at her baseline status. Follow-up angiography 1 year after the procedure confirmed remained occlusion of the shunt.

Results Skull base approaches and microsurgical disconnection remain very useful in the treatment armamentarium of DAVFs of the CCJ.

Conclusion Microsurgical disconnection of DAVFs of the CCJ represents a very important tool in our armamentarium for the treatment of these lesions. Understanding of their complex angiographic characteristics and knowledge of the various skull base approaches in the area of the CCJ are critical for the successful treatment of these pathologies.