Embolization of a spontaneous middle meningeal arteriovenous fistula that caused intracranial hemorrhage due to aneurysm rupture

A middle meningeal arteriovenous fistula (MMAVF) is a direct arteriovenous shunt between the middle meningeal artery (MMA) and adjacent venous structures. Most MMAVFs result from MMA tears due to trauma or iatrogenic injury. Spontaneous MMAVF as a result of true MMA aneurysm rupture is rare. Here, we report such a rare case. A 60-year-old male presented with subarachnoid, ventricular and epidural hemorrhages. He was previously healthy and denied a recent history of head injury or surgery. Upon examination, he was alert and could answer questions correctly. Computed tomography (CT) did not reveal any skull fractures. Digital subtraction angiography revealed a left MMAVF and that the true MMA aneurysm had ruptured, draining into the middle meningeal vein and other adjacent venous structures. Endovascular treatment (EVT) was performed. After the MMA was catheterized, the MMAVF was obliterated by casting Onyx. The patient experienced hydrocephalus on the 3rd postoperative day, which was resolved with drainage via an Ommaya catheter. On the 7th postoperative day, CT revealed that the intracranial hemorrhage had absorbed, and the hydrocephalus had regressed. Two weeks later, the patient had recovered well. According to this report, MMAVFs can spontaneously develop as a result of true MMA aneurysm rupture, resulting in intracranial hemorrhage. EVT by casting Onyx is an effective approach for MMAVFs.