[An interesting case of the traumatic middle meningeal arteriovenous fistula].

The authors reported an interesting case of the traumatic middle meningeal arteriovenous fistula which was caused by the minor head injury on the opposite side complicated with a subarachnoid hematoma, and was completely cured 35 days after head injury without any surgical intervention. A 75-year-old woman fell down after unconsciousness fit and hit her right head, then visited Matsuyama Shimin Hospital complaining of nausea, vomiting and severe left temporalgia. Neurologically, no other abnormalities were found. On plain skull roentogenograms, a linear fracture was noted on the right temporal bone, but not on the left side. A subarachnoid hematoma localized in the left Sylvian fissure was identified on plain computed tomograms. Left carotid angiograms revealed the middle meningeal arteriovenous fistula at the left middle fossa, which showed an characteristic drainages, i.e. mainly draining to the pterygoid venous plexus and the superior sagittal sinus, partially to the cavernous sinus. She was admitted to our ward and was treated only conservatively. Thirty-five days after head injury, her complaints improved remarkably and left carotid angiograms, performed on the next day, disclosed complete disappearance of the previous fistula, and suggested the point of fistula clearly. Documenting the computed tomogram and the angiograms of our case, possible mechanism of fistula formation and its spontaneous cure was discussed. The middle meningeal arteriovenous fistula was formed by the interaction between the direct or indirect influence of head injury and anatomical, histological and pathological factors of meningeal vessels themselves. Spontaneous cure of the fistula resulted from thrombosis at the point of fistula. In our case, irregularity of the wall of anterior middle meningeal artery on the repeated angiograms supported this view.