Introduction
Intracranial dural arteriovenous fistulas (DAVFs) are abnormal arteriovenous connections
located within the leaflets of the dura matter, commonly near the venous sinuses.
Arterial supply usually arises from dural or meningeal arteries. Dural branches from
the pial arteries are rare. Venous drainage may occur into the dural sinuses, dural,
osteodural, and/or leptomeningeal veins.[[1 ]],[[2 ]] Symptoms of the patients usually relate to the location of the fistulas and venous
drainage patterns.[[3 ]] Based on the pattern of venous drainage by Cognard et al.,[[4 ]] intracranial DAVFs were classified into five types, including Type I: Fistulas
drain into the main sinus with antegrade flow; Type IIa: Retrograde flow into the
sinus (es) only; Type IIb: Retrograde flow to cortical vein (s) only; Type III: Direct
cortical venous drainage without venous ectasia; Type IV: direct cortical venous drainage
with venous ectasia; and Type V: Into the spinal perimedullary veins. Patients harboring
DAVFs manifest with intracranial hemorrhage at initial diagnosis in approximately
18%–24% of all intracranial DAVFs.[[5 ]],[[6 ]] Foramen magnum DAVFs are rare and account for 1.5%–2.3% of all location of intracranial
DAVFs.[[4 ]],[[6 ]],[[7 ]],[[8 ]] DAVFs of this location usually occur in a middle-aged patient with a strong male
predominance. They commonly manifest with progressive myelopathy and posterior fossa
intracranial hemorrhage (i.e., subarachnoid hemorrhage [SAH]).[[9 ]]
We describe a patient with foramen magnum DAVF, Cognard type V, presenting with respiratory
insufficiency following by seizures, unconsciousness, and developing of cardiac arrest
caused by medullary hemorrhage from ruptured venous varix on the draining vein invaginated
into the medulla oblongata. We also review the literature of patients having foramen
magnum DAVFs.
Case Report
A 20-year-old smoker male experienced mild weakness and paresthesia of lower extremities
for 3 days. There was no underlying diseases or history of trauma. He went to the
clinic and took home some medicine. Three days later, the patient developed dyspnea,
generalized seizures, and subsequent loss of consciousness. He was sent to the emergency
department of the local hospital and intubated promptly. A few minutes later, the
patient had a cardiac arrest. Immediate cardiopulmonary resuscitation was performed
nine times until the presence of vital signs. Computed tomography (CT) scan of the
brain was obtained and showed a hyperdense lesion in the dorsal region of the left-sided
of the medulla oblongata, corresponding to medullary hemorrhage [[Figure 1 ]]. The patient was sent to the intensive care unit for close observation until clinical
stable. Ten days later, the patient was sent to another larger local hospital. Following
day, magnetic resonance imaging (MRI) of the brain revealed diffuse hyperintensity
of the medulla oblongata on fluid-attenuated inversion recovery and T2-weighted sequences,
corresponding to venous congestion or edema of the medulla. There were multiple dilated
flow voids surrounding the medulla, more prominent on the left side, with venous varix
embedded into the left-sided of the lower medulla. T1-weighted images demonstrate
a round mixed iso and crescent hyperintense lesion in the dorsal region of the enlarged
upper medulla, representing acute to subacute hematoma. The trajectory of hemorrhage
projected superiorly from the left-sided of the lower medulla into the mid-dorsal
region of the upper medulla [[Figure 2 ]]. Tracheostomy was performed due to prolonged intubation and recurrent pneumonia.
The disabled patient gradually improved and could follow command in the next 2 weeks
with quadriparesis status (power Grade 1–2/5). Two weeks later, the patient was transferred
to Prasat Neurological Institute (PNI) for further investigation and proper management.
The neurological examination revealed fully consciousness, evidence of spastic quadriparesis
(power grade 2–3/5), hyperreflexia of upper and lower extremities, and the presence
of Babinski's sign. Digital subtraction angiography (DSA) demonstrated DAVF of the
foramen magnum supplied mainly by dural branches of bilateral hypertrophic posterior
inferior cerebellar arteries (PICAs), slightly by the posterior meningeal branch of
the left vertebral artery (VA), and the neuromeningeal trunk of the left ascending
pharyngeal artery (APA) originating from the occipital artery. The venous drainage
was split in two directions via the dilated lateral medullary veins and run superiorly
along cerebellomedullary and cerebellopontine cisterns into both petrosal veins. On
the left side, the left basal vein of Rosenthal receives venous blood from the anterior
pontomesencephalic vein and the left lateral mesencephalic vein with subsequent drainage
into the great vein of Galen. On another side, the right dilated superior hemispheric
vein connects from the dilated right transverse pontine vein with further drainage
into the right proximal transverse sinus through the tentorial sinus [[Figure 3 ]]. Transarterial embolization through the bilateral dural branches of the PICAs was
successfully performed using N-butyl-2-cyanoacrylate (NBCA). Postembolization angiography
confirmed complete obliteration of the fistulas [[Figure 4 ]]. MRI of the brain obtained 1 week after endovascular treatment revealed a large
round mixed central isointense and peripheral hypointense mass with hyperintensity
in a venous aneurysm, probably representing a thrombosed venous aneurysm with resolving
hematoma. There was the disappearance of previously seen venous congestion of the
medulla and multiple dilated flow-voids surrounding the medulla [[Figure 5 ]]. The patient gradually improved, and tracheostomy tube was removed before discharging
home 2 weeks after treatment. Six months after endovascular treatment, the patient
showed no residual neurological deficits. Routine annual follow-up was scheduled for
him, but the patient was lost to follow-up without any reasons.
Figure 1: Computed tomography scan of the brain, obtained after initial aggressive symptoms,
shows a hyperdense lesion in the dorsal region of the left-sided of the medulla oblongata
(arrowhead), corresponding to acute medullary hemorrhage
Figure 2: Magnetic resonance imaging of the brain obtained 11 days after initial aggressive
symptoms. (a) Axial fluid-attenuated inversion recovery image shows diffuse edema
of the medulla with a venous varix embedded into the left-sided of the medulla. (b)
Axial T2-weighted image also reveals diffuse edema with prominent dilated flow-voids
surrounding the lower medulla. (c) Sagittal Tl-weighted image demonstrates a round
mixed iso and crescent hyperintense lesion in the dorsal region of the enlarged upper
medulla, representing acute to subacute hematoma. (d) Coronal gadolinium-enhanced
T1-weighted image discloses the trajectory of hemorrhage from the left-sided of the
lower medulla into the mid-dorsal region of the upper medulla. (e) Coronal T2*-weighted
gradient-echo (GRE) image shows thin hypointense rim of hemosiderin
Figure 3: Cerebral angiography of the brain obtained 1 month after initial symptoms. Anteroposterior
(a and c) and lateral views (b and d) of bilateral vertebral arteries injections show
dural arteriovenous fistulas of the foramen magnum mainly supplied by bilateral hypertrophic
posterior inferior cerebellar arteries. The posterior meningeal branch of the left
VA also feed the fistulas. Anteroposterior (e) and lateral (f) views of late venous
phase of the right vertebral artery injection demonstrate deep venous drainage to
both sides of the brainstem along cerebellomedullary and cerebellopontine cisterns.
On the left side, the left basal vein of Rosenthal receives venous blood from the
anterior pontomesencephalic vein (white arrowhead) and the left lateral mesencephalic
vein (black arrowhead) with subsequent drainage into the great vein of Galen. On the
right side, the right dilated superior hemispheric vein connects from the dilated
right transverse pontine vein with further drainage into the right proximal transverse
sinus via the tentorial vein (black arrow). In addition, anteroposterior (g) and lateral
(h) views of the left external carotid artery injection reveal the minimal supply
from the neuromeningeal trunk of the left ascending pharyngeal artery originating
from the occipital artery
Figure 4: Anteroposterior (a and c) and lateral (b and d) views of superselective catheterization
of bilateral posterior inferior cerebellar arteries injections clearly reveal dural
branches of both posterior inferior cerebellar arteries supplying the fistulas. During
embolization with two injections via the right posterior inferior cerebellar artery,
lateral views (e and f) demonstrate glue cast penetrating into the proximal draining
vein. Postembolization, anteroposterior (g) and lateral (h) views of the right vertebral
artery confirm complete obliteration of the fistulas
Figure 5: Magnetic resonance imaging of the brain obtained 1 week after endovascular treatment.
Coronal (a and b), axial (c and d) T2-weighted, axial (e), and sagittal (f) T1-weighted
magnetic resonance imaging reveal a large round mixed central isointense and peripheral
hypointense mass with hyperintensity in a venous aneurysm, probably representing a
thrombosed venous aneurysm with resolving hematoma. There was disappearance of previously
seen venous congestion of the medulla and multiple dilated flow-voids surrounding
the medulla
Seven years later, the patient experienced occipital headache without the stiffness
of the neck for 7 days. He went to the local hospital and was sent back to PNI again
due to the previous history of DAVFs of the foramen magnum. There were no neurological
deficits on neurological examination. Follow-up MRI of the brain showed multiple dilated
flow-voids, more prominent on the right side, along both cerebellomedullary and cerebellopontine
cisterns, representing recurrent DAVFs of the foramen magnum. There was the disappearance
of a previously seen thrombosed venous aneurysm and complete resolution of the hematoma
in the medulla with the small residual hypointense area of hemosiderin stain in the
dorsal region of the medulla [[Figure 6 ]]. DSA with angiographic CT in three-dimensional reconstruction and maximum intensity
projection (MIP) reformatted images of the craniocervical junction clearly demonstrated
the exact location of the DAVFs at the posterior rim of the foramen magnum, mainly
supplied by the hypertrophic jugular branch of the APA originating from the occipital
artery. Without supplying from the right PICA, the left PICA and posterior meningeal
branch of the left VA partially fed the fistulas. The venous drainage drained to both
sides of the medulla and run superiorly along cerebellomedullary and cerebellopontine
cisterns into both petrosal veins. On the left side, the fistulas drain superiorly
into the great vein of Galen through the left dilated vein of cerebellomesencephalic
fissure. On the right side, the fistulas still drained into the right proximal transverse
sinus through the dilated superior hemispheric vein and tentorial sinus, respectively.
Inferiorly, it also drains into anterior medullary vein connecting to anterior spinal
vein [[Figure 7 ]]. Endovascular treatment was performed through the jugular branch of the left APA
using NBCA [[Figure 8 ]]. DSA after embolization revealed residual fistulas. Due to incomplete obliteration
of the fistulas, the patient then was informed about surgical option and accepted
this option.
Figure 6: Magnetic resonance imaging (MRI) of the brain obtained 7 years after endovascular
treatment and the patient presented with occipital headache. Sagittal Tl-weghted (a),
sequential coronal (b and c), and axial (d, e, and f) T2 weighted MRI demonstrate
multiple dilated flow-voids, more prominent on the right side, along both cerebellomedullary
and cerebellopontine cisterns, representing recurrent dural arteriovenous fistulas
of the foramen magnum. There is disappearance of a previously seen thrombosed venous
aneurysm and complete resolution of the hematoma in the medulla with small residual
hypointense area of hemosiderin stain in the dorsal region of the medulla
Figure 7: Cerebral angiography obtained 7 years after endovascular treatment. Anteroposterior
(a), lateral (b) views, and anteroposterior 3-dimentional reconstructed image (c)
of the left external carotid artery injection demonstrate recurrent dural arteriovenous
fistulas of the foramen magnum mainly supplied by the hypertrophic neuromeningeal
trunk of the ascending pharyngeal artery (APA) originating from the occipital artery.
The fistulas drain to both sides of the brainstem along cerebellomedullary and cerebellopontine
cisterns. On the left side, the fistulas drain superiorly into the great vein of Galen
via the left dilated vein of cerebellomesencephalic fissure (black arrow). On the
right side, dilated superior hemispheric vein connects from the dilated petrosal vein.
Inferiorly, it also drains into anterior medullary vein connecting to anterior spinal
vein (white arrowhead). (d) Sagittal maximum intensity projection (MIP) reformatted
image of angiographic computerized tomography (CT) of the craniocervical junction
clearly shows the APA running along the floor of posterior fossa through the jugular
foramen. Anteroposterior (e) and lateral (f) views of the left vertebral artery injection
demonstrate the fistulas fed partially by the left posterior inferior cerebellar artery
and posterior meningeal branch of the left vertebral artery. Axial (g), sagittal (h),
and coronal (i) MIP reformatted images of angiographic CT of the craniocervical junction
clearly demonstrated the exact location of the fistulas at the posterior rim of the
foramen magnum and the anterior spinal vein (white arrowhead)
Figure 8: During embolization through the left ascending pharyngeal artery, the glue penetrates
into the proximal draining vein
Following suboccipital craniotomy without C1 laminectomy, resecting the dural leaflets
and disconnecting leptomeningeal medullary draining veins were successfully performed
using indocyanine green fluorescence imaging during operation [[Figure 9 ]]. In addition, watertight duraplasty was done with synthetic dural graft. The postoperative
course was uneventful. Follow-up DSA, obtained 1 month after surgery, confirmed complete
obliteration of the fistula [[Figure 10 ]]. The patient has remained clinically asymptomatic 2 years after the operation.
Figure 9: During s suboccipital craniotomy without C1 laminectomy on prone position. Intraoperative
views show a flap of the removed dural leaflets (a), connecting of arterialized veins
and the dural leaflets after flipping a flap (b), and the dural leaflets after complete
disconnection (c). (d) Indocyanine green fluorescence image confirmed complete removal
of the dural arteriovenous fistula
Figure 10: Follow-up cerebral angiography obtained 1 month after surgery. Anteroposterior (a),
lateral (b) views of the left vertebral artery, and lateral view of the left external
carotid artery (c) injections confirm complete obliteration of the fistula
Discussion
The common etiologies of the medullary hemorrhages are cavernous malformation or hemorrhagic
transformation following infarction.[[10 ]] To the best of our knowledge, there was only one previously reported case of medullary
hemorrhage caused by DAVF at the craniocervical junction, supplied by the meningeal
branch of the VA with draining superiorly into the anterior medullary vein in elderly
woman.[[11 ]] She was complicated by acute neurogenic pulmonary edema, resulting in acute respiratory
distress syndrome. In the present study, our case was the first case report of foramen
magnum DAVF presented with acute medullary hemorrhage, leading to respiratory dysfunction,
subsequent seizure, and finally developing cardiac arrest.
Involuntary convulsive-like movements, for example, jerky, tonic-clonic, intermittent
shaking, or decerebrate postures, may occur in patients with brainstem stroke.[[12 ]] Without electroencephalography, we could not conclude that our case had real seizures.
However, foramen magnum DAVF may present with epilepsy due to venous drainage superiorly
to the temporal lobe, leading to temporal venous congestion.[[13 ]]
According to Cognard classification,[[4 ]] a foramen magnum DAVF with perimedullary and spinal venous drainage in our case
is classified as Type V. The patients with Cognard type V intracranial DAVFs may experience
bulbar palsy, and/or respiratory failure due to medullary venous congestion.[[14 ]] Without descriptions in details, Cognard et al.[[4 ]] disclosed that all three cases of foramen magnum DAVFs, classified as Cognard type
IV and V, presented with hemorrhages. Based on the study of the relation between clinical
presentation and venous drainage of intracranial DAVFs with spinal venous drainage
by Brunereau et al.,[[15 ]] they found that the patients presenting with hemorrhage had venous drainage limited
to the cervical cord, whereas those with myelopathy had extensive spinal venous drainage
descending toward the conus medullaris.
The common types of hemorrhage in intracranial DAVFs are SAH and intracerebral hemorrhage.[[3 ]],[[16 ]] Brainstem hemorrhage is extremely rare. Nakajima et al.[[17 ]] reported an elderly man with DAVFs of the sinus of the lesser sphenoid wing presented
with pontine hemorrhage caused by venous varix on lateral mesencephalic vein invaginated
into the pons. Another case report by Lasjaunias et al.,[[1 ]] they demonstrated small midbrain hemorrhage probably caused by ruptured perimesencephalic
draining vein from a foramen magnum DAVF in middle-aged man.
The presence of retrograde cortical venous drainage or leptomeningeal venous drainage
in DAVFs is the most imperative risk factor of intracranial DAVFs associated with
hemorrhage.[[6 ]],[[18 ]],[[19 ]] In multivariate logistic regression analysis by Singh et al.,[[5 ]] male gender, age older than 50, and posterior fossa location were also found to
be independently associated with hemorrhagic manifestation. In addition, smoking was
more common in the hemorrhagic group. In our case, there were many risk factors, including
retrograde leptomeningeal venous drainage, male gender, posterior fossa location,
and history of smoking, except young age.
We reviewed the published case reports which have sufficient clinical description
and clearly demonstrated figures of foramen magnum DAVFs.[[3 ]],[[9 ]],[[13 ]],[[16 ]],[[20 ]],[[21 ]],[[22 ]],[[23 ]],[[24 ]],[[25 ]],[[26 ]],[[27 ]],[[28 ]],[[29 ]],[[30 ]],[[31 ]],[[32 ]],[[33 ]],[[34 ]],[[35 ]] The collected data in this review include demographic data (i.e., gender and age
of patient), presenting symptoms, the findings of image studies, arterial feeders
of the fistula, location of the draining veins, the presence of venous varix, treatment
of the fistula, and neurological outcomes following treatment [[Table 1 ]]. From the literature review, there were 27 cases, including our case, with 27 foramen
magnum DAVFs. All patients except one were male (96.3%) with a median age 49, range
20–69 years. Of 27 cases, 15 (55.6%) were hemorrhagic presentation, including SAH,
intraventricular hemorrhage, cerebellar hemorrhage, and medullary hemorrhage (our
case). The most common type of hemorrhage was SAH (80%). Another 12 cases were non-hemorrhagic
presentation, including progressive myelopathy, epilepsy, tinnitus, floating sensation.
The median age in hemorrhagic group was 46 (range 20–58 years), whereas nonhemorrhagic
group was 51.5 (range 38–69 years). Only 2 cases, including our case, presented with
myelopathy and hemorrhage. Most patients with hemorrhagic manifestation had a venous
varix being the source of hemorrhage. The arterial supply included APA, VA, OA, and/or
PICA. Twenty-two foramen magnum DAVFs (81.5%) supplied by the branch of APA, including
hypoglossal and/or jugular branches. Four cases had blood supply only from VA. Only
our case had additional supply from PICA. All patients with progressive myelopathy
had venous drainage into the spinal cord, i.e., Cognard Type V. Four cases, including
our cases, had respiratory insufficiency resulting from venous drainage to the medulla,
leading to medullary congestion. Eighteen fistulas were treated with endovascular
treatment alone, five with surgery alone, three with surgery following embolization,
and one left untreated. Most embolic material used for treatment was liquid embolic
material, including glue and Onyx. Most patients had good neurological outcome after
treatment.
Table 1: Literature review of foramen magnum dural arteriovenous fistulas
Table 1: Contd...
Retrograde leptomeningeal venous drainage, aneurysmal venous dilatation, and galenic
drainage are factors predisposing to aggressive neurological presentation, i.e., intracranial
hemorrhage or progressive neurological deficit.[[2 ]] Undoubtedly, leptomeningeal draining pathway with venous varix embedded into the
medulla is the source of hemorrhage, leading to catastrophic neurological behavior
in our case. Furthermore, we previously reviewed a rare condition of patients suffering
from intramedullary hemorrhage caused by spinal DAVFs.[[36 ]] In most of the cases, venous varices on draining veins were the source of intramedullary
hemorrhage. Similar to our case, Kai et al.[[24 ]] demonstrated a false aneurysm protruding into the medulla. However, this case presented
with SAH. In addition, Motebejane and Choi [[9 ]] revealed that all patients harboring foramen magnum DAVFs with SAH in their series
had intracranial venous drainage with venous aneurysms. Based on our review, hemorrhage
in foramen magnum DAVFs usually resulted from ruptured venous varix.
Foramen magnum DAVFs can be treated by endovascular treatment, surgery, or both depend
on institutions preference.[[9 ]],[[16 ]],[[27 ]],[[30 ]] However, best management decisions should be approached by a multidisciplinary
team.[[3 ]] DAVFs in the region of the foramen magnum tend to have leptomeningeal venous reflux
and a high risk for intracranial hemorrhage. Therefore, aggressive treatment should
be achieved.[[24 ]] The goal of treatment is to obtain the anatomical cure.[[16 ]]
Interestingly, the foramen magnum DAVF in our case mainly supplied by bilateral PICAs,
i.e., pial arteries. Only 5% of all intracranial DAVFs supplied by both meningeal
and pial arteries.[[4 ]] DAVFs fed by the pial arteries are associated with a higher risk of stroke or major
complications either during endovascular or surgical treatment.[[37 ]] Osada and Krings [[38 ]] investigated the characteristics of pial arterial supplies in intracranial DAVFs
and classified them into dilated pre-existing dural branches of pial arteries and
a pure pial supply. Younger age, DAVFs within tentorium, and the presence of venous
dilatation (i.e., a sign of venous hypertension) were independent predictors of a
pial arterial supply. In their series, they also reported dilated dural branch of
pial arteries from PICA in DVAFs of tentorium, torcular herophili, and foramen magnum
DAVFs. Recognition of additional pial supply is imperative for avoiding inadvertent
complication related to the reflux of liquid embolic materials into pial vessels supplying
normal brain tissue. Dural vessels arising from PICA are the posterior meningeal artery
and the artery of the falx cerebelli.[[39 ]] Onyx embolization in DAVFs through pial arterial supply could increase the risk
of procedure-related complications, i.e., periprocedure hemorrhage.[[40 ]] In our case, the posterior meningeal arteries from PICAs pierced the dura at the
posterior rim of the foramen magnum. Fortunately, the fistula was successfully treated
using NBCA via these branches without any complications.
Medullary congestion can be either due to intracranial DAVFs with caudally drainage
into the anterior spinal vein through the medullary or cervical DAVFs with rostrally
drainage into medullary veins.[[4 ]],[[41 ]] According to a systemic review by El Asri et al.,[[42 ]] the poor outcomes were correlated to the presence of brainstem signal abnormalities
on MRI. Unlike primary intracerebral hemorrhage, the patient suffering from extensive
hemorrhagic venous infarction even caused by high-flow AVF may dramatically recover
following prompt endovascular treatment.[[43 ]] In our case, the patient had regained full motor strength without residual neurological
deficits after marked reduction of the flow of the fistula by transarterial embolization
using NBCA through pial supply of bilateral PICAs.
Incomplete embolization, using non-permanent embolic, or partial surgical of the fistula
may result in recurrent fistula, probably leading to fatal rebleeding.[[16 ]] Even though using transarterial embolization with Onyx, the recurrence of the fistula
can occur.[[13 ]] Therefore, long-term follow-up with radiographical images is mandatory to early
detect the recurrent fistula. Recanalization of embolized vessels occurred in our
case several years later with the manifestation of occipital headache. The fistula
also recruited other feeding artery, i.e., the APA.
Motebejane and Choi [[9 ]] demonstrated that all foramen magnum DAVFs in their series were supplied by the
hypoglossal and/or jugular branches of the APA, commonly by hypoglossal branch. The
APA may arise from the proximal occipital artery.[[44 ]] With angiographic CT in three-dimensional reconstruction and MIP reformatted images,
in our case clearly demonstrated the jugular branch of the APA originating from the
occipital artery. Given delay in treatment and probable subsequent poor outcomes,
DAVFs at the foramen magnum may not be identified using standard 4 vessels cerebral
angiography.[[20 ]],[[21 ]],[[24 ]] Due to common feeder by the neuromeningeal trunk of the APA, selective ascending
pharyngeal angiography should be performed. Endovascular treatment through this artery
may carry the risks of inadvertent embolization due to potential risk of liquid embolic
materials leakage through extracranial-intracranial anastomoses or injury to vasa
nervosum of cranial nerves.[[3 ]] To prevent major reflux into the main trunk, the tip of the microcatheter should
be navigated close enough to the fistula.[[35 ]] In addition, balloon-augmented liquid embolic material embolization through neuromeningeal
trunk of APA was used to prevent the risks of injury to the lower cranial nerves.[[9 ]],[[31 ]],[[33 ]] Transarterial embolization alone is likely to be ineffective due to the extensive
collateral network and high vascularity of the dura.[[24 ]] Predictably, there was residual fistula following transarterial embolization through
the APA using NBCA in our case.
MRI and cerebral angiography may not depict the exact location of the fistulas at
the skull base.[[21 ]] We agree with Pop et al.[[13 ]] that rotational angiographic CT is useful in delineating the complex anatomy of
the foramen magnum DAVFs. In our case, angiographic CT in three-dimensional reconstructed
image and MIP reformatted images can identify the exact location of fistula at the
posterior border of the foramen magnum and complex venous drainages.
According to the literature review in Cognard type V intracranial DAVFs by El Asri
et al.,[[42 ]] the surgical treatment appears to be more effective than endovascular treatment.
Microsurgical treatment of foramen magnum DAVFs probably is an effective and more
reliable method of treatment.[[27 ]] Many surgeons preferred suboccipital approach with partial or hemilaminectomy for
foramen magnum DAVFs.[[3 ]],[[27 ]],[[30 ]],[[34 ]] In our case, suboccipital approach without laminectomy of C1 was enough for resecting
the dural leaflets and disconnecting leptomeningeal veins due to knowing the exact
location of the fistula from angiographic CT.
Conclusion
We illustrated an extremely rare case of foramen magnum DAVF, Cognard type V, presented
with catastrophic neurological behavior, caused by ruptured venous varix, leading
to medullary hemorrhage. The patient had a complete recovery after endovascular treatment
via bilateral PICAs with complete obliteration of the fistula. Seven years later,
he had a recurrent DAVF presented with occipital headache. The fistula recruited mainly
blood supply from the jugular branch of the APA originating from the occipital artery.
Finally, we could achieve a cure of the DAVF by surgical removal of the dural leaflets
and disconnection of the fistula following endovascular treatment via the APA with
excellent outcome. Understanding the angioarchitecture of foramen magnum DAVFs, including
arterial feeders, venous drainage pattern, associated venous pouch, and localization
of the fistulous zone, is the key to successful management. In addition, the exact
location of DAVFs may influence the surgical approach.
Consent
The patient has given consent to be enrolled and has her data published.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms.
In the form, the patient has given her consent for her images and other clinical information
to be reported in the journal. The patient understands that name and initials will
not be published, and due efforts will be made to conceal identity, but anonymity
cannot be guaranteed.
