A 45-year-old man was admitted for a progressively worsening headache over 2 weeks. He denied history of recent head trauma or anticoagulation and antiplatelet medication. General and neurologic examinations were not remarkable on admission. Routine laboratory investigations including coagulation profiles and platelet function were within normal limits. Head computed tomography (CT) on admission revealed an isodense CSDH on the right hemisphere with mild midline shift (Fig. a). A CT angiography (CTA) was performed to rule out any intracranial vascular malformation. A DAVF was noticed at the transverse sinus with dilated cortical venous drainage (Fig. b). So, a digital subtraction angiography (DSA) of the external carotid artery and DAVF embolization was planned.\nNo anomaly was noticed during selective angiography of the internal carotid and vertebral arteries and the left external carotid artery. Selective angiography of the right external carotid artery showed that the DAVF was located at the transverse sinus and fed by posterior branch of the middle meningeal artery (MMA), the occipital artery, and the posterior meningeal artery and drained to the occipital cortical veins with venous ectasia (Fig. a-b). The DAVF was classified as type IV according to the Cognard classification. The embolization was performed via the MMA. The Headway duo catheter was used and accessed to the DAVF, and Onyx was injected until the shunt disappeared (Fig. c-d). The patient experienced an uneventful recovery. His CSDH gradually resolved in 1 month (Fig. ). No neurologic deficit was noticed.\nA PubMed search of published studies written in English and Chinese was conducted on June 30th, 2017. The following key words were used in relevant combinations: dural arteriovenous fistula, dural arteriovenous malformation, subdural hematoma, subdural haematoma, subdural hemorrhage, and subdural haemorrhage. The reference lists of the identified articles were also manually searched for additional studies. Studies of which full text could not be obtained or those without sufficient individualized description of the isolated SDH cases mixed in larger case series were excluded.\nFinally, 13 articles containing 14 patients were identified [–]. In all 15 patients (9 females, 60%) including 1 case in our institution were included for the final interpretation (Table ). The inflicted patients were aged from 27 to 82 years (55.5 ± 8.6).Of note, 12 (80%) of the 15 patients were aged between 40 and 60 years of age, and 8 (53.3%) patients were between 50 and 60 years. Sides of the DAVF or SDH were obtained in 13 patients with 9 (69.2%) located at the left side and 4 at the right side. The intracranial locations of DAVF were anterior fossa (2), middle fossa (2), frontal region (2), parietal region (3), temporal region (2), and occipital region (2). The types of SDH were CSDH (7/15), acute SDH (ASDH) (7/15), and undefined SDH (1/15). Of the 12 patients feeding artery could be identified, MMA was the commonest feeding artery (8/12, 66.7%). Multiple feeding arteries were identified in 3 (25%) patients. The causes of DAVF were only defined in 3 patients (2 iatrogenic and 1 traumatic), with the rest undefined or not mentioned. Cognard classifications (Table ) of the DAVF were reported or deduced from the reports in 12 patients, with type I, type III, and type IV in 7, 2, and 3 patients respectively. The treatment strategies included hematoma evacuation (2/15), CSDH drainage and DAVF embolization (5/15), craniotomy and DAVF resection (3/15), DAVF embolization and hematoma evacuation (1/15), DAVF embolization (2/15), and not applicable or not mentioned (2/15). Of the 12 patients with direct description of outcome, 7 (58.3%) patients were neurological intact, 3 (25%) patients with neurological deficits, and 2 (16.7%) died.
This 67-year-old male man has had a progressively worsening pain on the left cranium over 2 weeks that intractable to some analgesics. There was no recent head trauma or other medical disease in his history. On admission, the general physical and neurologic investigations were not remarkable. Routine laboratory evaluations including coagulation profiles and platelet function were within normal limits.\nBrain computed tomography (CT) scans revealed an isodense left-sided CSDH with marked cerebral shifting (). There was no evidence of source of this hemorrhage with temporal predilection on the CT angiogram. On magnetic resonance (MR) image subsequently obtained, the abnormal intensity within the subarachnoid space and the brain parenchyma was not visible. The patency without steno-occlusion in both transverse and sigmoid sinuses was clearly delineated on T2-weighted sequences (). This patient has received a trephination and SDH drainage, after that he was sent home with resolution of headache. Approximately 2 weeks later, however, he developed an excruciating pain in the temporal and parietal regions with recurrence of subdural collection. The site and density of hematoma was similar to the first presentation (). He was immediately returned for subdural irrigation and decompression through the prior burr-holes. The patient's clinical course was not eventful, but he complained of a mild headache again. Follow-up CT scanned just prior to discharge was strikingly for the newly-formed thin hematoma at the operative site (). Another evacuation of this subacute subdural clot was not deemed to be necessary.\nAt this time, an active intervention was sought for this patient who had an intractably recurring CSDH. On the 7th day after the second surgery, angiography was performed to rule out an occult vascular lesion. A flow-guided type microcatheter (Prowler 10™, Cordis Neurovascular, Miami Lakes, FL, USA) was positioned in the main trunk of the MMA for selective angiography. The frontal and parietal branch of the MMA was appeared normally, and the abnormal membrane staining on the affected side was not detected. A left external carotid angiogram disclosed a dural AVF between the petrosquamosal branch of the MMA and the transverse-sigmoid sinus without retrograde cortical venous draining. The AV shunt had no connection to the internal carotid artery and its branches. It was suggested that the bleeding from the draining venous system of the dural AVF led to refractory CSDH. The microcatheter was introduced into the petrosquamosal branch of the MMA, thereafter polyvinyl alcohol particles ranging 150 to 250 µm were distally injected (). After trans-arterial obliteration of the feeder and fistula, the AV shunt disappeared. The recurrent hematoma of this patient did not increase, and his complaints of headache gradually subsided. The brain CT at one year following the embolization therapy revealed complete regression of the subdural hematomas ().