intracranial pial arteriovenous fistula ( avfs ) are rare cerebrovascular lesions of the brain that have recently been recognized as a distinct pathological entity , differing from the cerebral arteriovenous malformations ( avms ) in that they lack a true nidus . according to a series reported by halbach et al .
( 1 ) , intracranial pial avfs account for 1.6% of all intracranial vascular malformations . however , congenital avfs draining into the cavernous sinus in infants are very rare . here
we present the first case of a congenital pial avf between the temporal branch of the left posterior cerebral artery ( pca ) and the left cavernous sinus through the sphenoparietal sinus , successfully treated by a vertebrobasilar approach with the use of two detachable micro - coils .
a 4-month - old infant was admitted to the department of ophthalmology in our hospital with progressive proptosis and redness of his left eye since birth .
he was uneventfully delivered at full term , weighing 3.1 kg , and from a healthy mother .
there were no signs of irritability , fever or disturbance of swallowing , and weight gain was good .
however , the physical examination revealed engorged conjunctiva , tortuous episcleral vessels , and swollen left eyelids .
a slight intermittent systolic bruit was heard over the left global , whose rhythm was consistent with the heartbeat .
the ophthalmologist strongly suspected cerebrovascular pathology , so the baby was transferred to the department of neurosurgery .
an mri examination revealed orbital edema , proptosis , enlargement and tortuosity of the superior ophthalmic vein , prominence of the left cavernous sinus and enlargement of the extraocular muscles ( fig .
1a ) . digital subtraction angiography ( dsa ) confirmed the diagnosis , classifying the fistula , and delineating the venous pathways .
a left single hole fistula was confirmed at the temporal branch of the pca draining directly to cavernous sinus ( fig .
after multidisciplinary consultation and consent of their families , endovascular treatment was proposed for this infant .
the endovascular treatment was performed under general anesthesia and under full intravenous heparinization . via a right percutaneous femoral access , a 4 fr guiding catheter ( evoy , cordis , johnson & johnson co. , washington dc , usa ) was place in the left vertebral artery .
the micro - catheter was inserted into the cavernous sinus through the temporal branch of pca under the guidance of road mapping .
then micro - coils were deployed in the cavernous sinus through the micro - catheter .
cerebral angiography was repeated sequentially after a coil was filled while checking for occlusion of the fistula ( fig .
finally , the fistula was filled with two detachable micro - coils ( 5 mm  15 cm , 4 mm  8 cm ) that completed occluded the fistula ( fig .
the systolic blood pressure was kept at approximately 80% of the basal blood pressure for 72 hours after the embolization .
intracranial pial avfs are rare cerebrovascular lesions , representing only 1.6% of all brain avms in larger reported series ( 1 ) .
they have recently been recognized as a distinct pathological entity from other intracranial avms . unlike the cerebral avms and dural avfs , pial avfs are comprised of one or more arterial connections to a single venous channel without any intervening nidus of vessels or capillaries .
congenital pial avfs are very rare , and little is known regarding their pathophysiological mechanisms .
abnormal angiogenesis , cytokines and associated vascular growth factors may play a role in the formation of congenital pial avfs , and it is possible that an embryological misstep could produce these lesions ( 2 ) .
this case is a congenital pial avf between the temporal branch of the left posterior cerebral artery and the left cavernous sinus through the sphenoparietal sinus .
anatomically , temporal poles can drain into the sphenoparietal sinus and cavernous sinus ( 3 ) .
thus , this type of avf can occur , although no case like this has been reported .
similar to the carotid cavernous fistulas , a congenital pial arteriovenous fistula draining into cavernous sinus can cause bruit , proptosis , conjunctiva chemosis and symptoms referable to the optic and trigeminal nerves .
fistulas in newborns and infants manifest as enlarged head circumference , heart failure , seizures or intracranial hemorrhage ( 4 - 7 ) . in our case ,
the infant presented only with progressive proptosis and redness of his left eye , so he was admitted to the department of ophthalmology initially .
if this infant was continually misdiagnosed as an eye disease , the outcome may have been intracranial hemorrhage or heart failure .
little research concerning the natural history of these lesions has been published because they are so rare .
there are a few reports regarding spontaneous resolution of a congenital pial avf draining into the cavernous sinus ( 2 , 8) . according to one report ( 9 )
, conservative management of pial avf was associated with mortality in five ( 63% ) of eight patients , so spontaneous closure of pial avfs is not expected . in our case ,
the infant had a high - flow , single hole fistula , and the clinical manifestations gradually worsened day by day .
active treatment was necessarily implemented once diagnosed clearly to prevent fatal cerebral hemorrhage and worst neurocognitive prognosis .
endovascular embolization has been proven more efficacious and safe than open surgery in the treatment of cerebral avfs .
a number of different embolization materials options for cerebral avfs are currently available , such as detachable balloons , detachable micro - coils and onyx .
probably the detachable balloon and the onyx are the first choice for traumatic carotid cavernous fitulas and dural cerebral avfs ( 2 , 9 , 10 ) .
however , micro - coils were used in our case instead of detachable balloon and onyx .
there were two reasons : the femoral artery of the infant was too small to allow the placement of the 8 fr catheter sheath , and the balloon could not pass through the 4 fr guiding catheter , while the branch of the pca was very close to the fistula , and onyx may reflux into the pca ( 11 ) .
though the fistula was a high flow , it was successfully occluded only with two micro - coils , and angiogram by fluoroscope revealed that the fistula was completely occluded with loose packing . to prevent fistula recanalization ,
the main danger is post - operation cerebral hemorrhage of the feeding arteries , which must be controlled by strict blood pressure monitoring while maintaining the systolic blood pressure at approximately 80% of the basal blood pressure for 72 hours after embolization .
the stable occlusion of the fistula has been demonstrated by mri examination at 9 months .
 this report concerns a 4-month - old infant with progressive prominent and redness of his left eye since birth . 
 this report concerns a 4-month - old infant with progressive prominent redness of his left eye since birth . 
 angiography revealed a congenital pial arteriovenous fistula between the temporal branch of the left posterior cerebral artery and left cavernous sinus through the sphenoparietal sinus , a condition not reported in the literature . 
 the fistula was successfully occluded with two micro - coils by vertebrobasilar approach . 
INTRODUCTION
CASE REPORT
DISCUSSION