chronic subdural hematoma ( csdh ) is a common disease in modern neurosurgery practice especially for the elderly patients .
in contrast , non - traumatic subdural hematoma ( sdh ) caused by intracranial arteriovenous fistula ( avf ) is extremely rare , and there are only a few cases described in the literature.8)13 ) furthermore , dural avfs are usually accompanied by intracerebral hemorrhage ( ich ) or subarachnoid hemorrhage ( sah ) , but they hardly ever present with the acute or chronic sdh.3 ) the author reports herein an interesting case of recurrent csdh primarily associated with dural avf which required repeat craniostomy and finally cured with embolization of middle meningeal artery .
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 ,
brain computed tomography ( ct ) scans revealed an isodense left - sided csdh with marked cerebral shifting ( fig .
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 ( fig .
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 .
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 ( fig .
another evacuation of this subacute subdural clot was not deemed to be necessary . at this time ,
on the 7 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 .
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 m were distally injected ( fig .
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 ( fig .
intracranial dural avfs are pathologic communications between dural arteries and dural venous sinuses , meningeal veins , or cortical veins .
these uncommon conditions are usually located in the transverse , sigmoid , cavernous , and superior sagittal sinus.2 ) the characteristic imaging feature is thrombosed sinus , dilated vessel , and hemorrhage within the adjacent cerebrum.17 ) in the present case ,
angiograms indicated the existence of dural veins that were connected to the anomalous artery arising from the left mma at the lower posterior convexity . therefore , the author made a firm diagnosis of a dural avf in the area of the transverse - sigmoid sinus , and it was assumed that the oozing from the route of drainage with high flow inputs was responsible for the progression and relapse of csdh.16 ) another explanation for refractory csdh is that repeated bleeding into the subdural space caused by the rupture of neo - vessels in an external membrane of hematoma.7)10)13 ) however , angiography of this patient did not visualize cotton wool - like staining along the branches of the mma , which is microcapillary network of the hematoma membrane .
dural avfs have various clinical manifestations from aggressive neurological defects to no or minor symptoms and signs depending mainly on the pattern of abnormal drainage of the veins.1 ) classification systems which are based on its mode of venous flow are used in cases of davf to estimate hemorrhage risks and to decide management strategies.4 ) intracranial hemorrhage occurs in less than 20% of all these pathologies , and the bleeding is usually subarachnoid , more infrequently intra - parenchymal , and rarely in the subdural space.19 ) for that reason , the presence of dural avf was not initially considered in the author 's case with only csdh without ich and sah . in the pertinent literature ,
there have been only 4 documented cases with idiopathic dural avf complicated by acute non - traumatic sdh.5)6)7)8 ) dural avfs near the superior sagittal sinus were confirmed by cerebral angiogram in all of them .
the sinus was well delineated as the drainer in those cases and in this report ; however , angiography did not show a retrograde drainage into the cortical veins in the vicinity of the fistulas .
the initial complaint was acute headache in the five patients including this representative case , but this is a unique illustration of the case with dural avf that complicated pure csdh.3 ) non - traumatic csdh is an uncommon pathology in neurosurgery , and its diagnosis and treatment is a not straightforward process .
neurosurgeons must be aware of the differential diagnosis for spontaneous csdhs because those develop secondarily to a few kinds of vascular lesion , such as aneurysms , arterial rents , arteriovenous malformations , intracranial avfs , and veno - sinus thrombosis.8)9)15)18)21 ) according to literature review , a few cases with sdh or effusion , an exclusive revelation of cerebral veno - sinus thrombosis , have been reported thus far.10 ) it has been proposed that the formation of sdh in this rare occurrence was associated with increased venous and capillary pressure.11 ) both ct and mr scans with arterio - venography are necessary to detect an occult vascular lesion and to prevent future problems in patients with a non - traumatic csdhs .
in addition , conventional angiography is the most valuable and decisive means for such patients and both internal and external carotid injections are essential for diagnosis and therapy .
this briefing implies that dural avf might be the cause of rare cases with intractable csdh that were cured by the craniotomy and extensive membranectomy .
craniostomy and intravascular approach provides the least invasive and definitive treatment for the rare condition of csdh and coexisting dural avf .
trans - venous embolization , which is one of the most effective therapies for dural avfs , is now considered as an alternative to the craniotomy and excision in many cases.14 ) trans - arterial embolization may be beneficial to another patients had a dural avf , although it often lead to incomplete occlusion of the venous pouch.20 ) in the present case , however , the avf can be secured by trans - arterial approach through the left mma , because it was not difficult to select and penetrate the dural feeder in a single session . during the trans - arterial procedure
, liquid embolic materials should penetrate into the draining veins to obliterate the fistula permanently.12 ) for this illustrative case , after the super - selective advancing a microcatheter to the draining vein , the interventionist administered polyvinyl alcohol particle into the fistula and veins , and the dural avf was completely eliminated .
the author reported on a non - traumatic case who initially presented with csdh caused by bleeding from a dural avf involving the transverse - sigmoid sinus .
brain investigation including dynamic mr image and ct venography and catheter angiography is strongly recommended for the cases with acute sdh and intractable csdh of obscure origin .
 the author has encountered a 67-year - old man with dural arteriovenous fistula ( avf ) presenting as a non - traumatic chronic subdural hematoma ( csdh ) . 
 this previously healthy patient was hospitalized due to progressive headache with subacute onset . 
 he underwent burr - hole surgery twice for evacuating the left csdh that was thickest at the posterior temporal area . 
 the operative procedure and finding was not extraordinary , but subdural hematoma slowly progressed for days following the revision surgery . 
 after investigation by super - selective external carotid angiography , a dural avf found near the transverse - sigmoid sinus was diagnosed . 
 dural avf was completely occluded with trans - arterial injecting polyvinyl alchol particles into the petrosquamosal branch of the middle meningeal artery . 
 the patient showed a good neurological outcome with no additional intervention . 
 brain surgeons have to consider the possibility of dural avf and perform cerebral angiogram if necessary when they manage the cases that have a spontaneously occurred and repeatedly recurring csdh . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION