Transcript Dural Arteriovenous Fistulas (dAVFs)

Dural Arteriovenous
Fistulas (dAVFs)
Βασίλειος Ραπτόπουλος
Νευροχειρουργική κλινική
ΓΝΑ «Γ.Γεννηματάς»
Definition
Abnormal arteriovenous shunts
within the dural leaflets
in AVMs: nidus in pia mater, no dural feeders
dAVFs
• 5-20% of all intracranial malformations
• Most common acquired intracranial vascular malformation
• 6th – 7th decade
• Arterial supply from dural arteries (less common: osseous
branches)
• Venous drainage via dural venous sinus, cortical veins or both
• Symptoms secondary to venous congestion
• 8% multiple dAVFs
Pathogenesis
?Head injury
?Craniotomy
?Hypercoagulability
???
Recanalisation
Venous
hypertension
Pre-existing dural
microvascular channels
Sinus
thrombosis
•Enlarged by venous hypertension
Neoangiogenesis
•BFGF, VEGF
Dural AVF formation
Clinical Presentation
• Pulsatile tinnitus, objective bruit
• Haemorrhage (ICH, SDH, SAH, IVH)
• NHND (Non-hemorragic neurological deficit)
• Focal
• Global
• Visual disturbances
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•
•
•
Opthalmoplegia
Visual loss
Glaucoma
Papilledema
• Facial pain (compression of V1, V2 at the lateral wall of the cavernous sinus)
Diagnosis
• Golden Standard: 6-vessel angiography
• Presence or absence of CVR (determination of
the exact site)
• Venous sinus occlusion *
• Direction of flow in sinuses
• Venous drainage pattern of brain
• ?MRI/MRA
* Careful in symptomatic patients!! - deficits may improve with restoration of normal flow
Classification
Borden Classification
Cognard Classification
Type I: Drainage into venous sinus or
meningeal vein only
Type I: Drainage into dural venous sinus only,
antegrade flow
Type IIa: Drainage into dural venous sinus only,
retrograde flow
Type II: Drainage into dural venous
sinus or meningeal vein + CVR*
Type IIb: Drainage into dural venous sinus (antegrade
flow) + CVR
Type IIa+b: Drainage into dural venous sinus
(retrograde flow) + CVR
Type III: CVR only
Type III: CVR only without venous ectasia
Type IV: CVR only with venous ectasia
*CVR: Cortical Vein Reflux
Type V: Drainage into spinal perimedullary veins
Natural History
Borden
Type
I
II
III
Aggressive
Presentation %
2%
39%
79%
Aggressive presentation defined
as ICH, NHND or death as the
presenting symptom
Davies et al., “The validity of classification for the clinical
presentation of intracranial dAVFs”, J Neurosurg 1996
Management Options
Observation
• For dAVFs without CVR
• ANY change in symptoms might signal development of CVR (2-3%)
• Serial MRI/MRA + angiogram after 3 years
Endovascular
• Transarterial embolization (palliative or preoperative)
• Transvenous embolisation
Surgical
• Venous access + direct packing of sinus
• Surgical excision
• CVR disconnection
Borden type I
• Benign natural history: 2% of
ICH, NHND (Van Dijk et al,
2002)
• 2-3% to develop CVR
• Palliative or no treatment
Right occipital artery, antegrade flow into
transverse/sigmoid sinus (Cognard I)
Left vertebral artery, retrograde flow into
transverse/sigmoid sinus (Cognard IIa)
Management Strategy
No CVR (Borden I, Cognard I, IIa)
Asymptomatic or tolerable symptoms
Intolerable symptoms
Observation
Palliative treatment (e.g., endovascular
transarterial embolization of feeders)
Benign Fistulas
No change in
Symptoms
Worse OR Better
Continue Observation
Serial MRI + MRA
Repeat angiogram in
3 years
Repeat angiogram
Borden type II
• Type II + III: 15% annual risk
of rebleeding
• 35% rebleed within 2
weeks (one series)
• Complex management
strategy – multidisciplinary
approach
LECA angiogram, superficial temporal
artery, antegrade flow into SSS, with CVR
(Cognard IIb)
LECA angiogram, occipital artery,
retrograde flow into transverse sinus, with
CVR (Cognard IIa+b)
Management Strategy
CVR and sinosal drainage (Borden II, Cognard IIb, IIa+b)
Aggressive
Fistulas (with
sinus drainage)
No neurological deficit
Neurological deficit secondary to
venous congestion
Assess venous phase of angiogram
Interruption of feeding arteries only
(transarterial endovascular or surgical)
Sinus not used by brain
Sinus used by brain
Complete obliteration or excision of
lesion including sinus sacrifice
OR
CVR disconnection only (endovascular
transvenour or surgical)
CVR disconnection only (endovascular
transvenous or surgical)
Borden type III
RECA angiogram, superficial temporal artery, CVR,
no ectasia (Cognard III)
RECA angiogram, posterior branch of MMA, ectatic
cortical vein drainage(Cognard IV)
Management Strategy
CVR only (Borden III, Cognard III, IV, V)
Aggressive
Fistulas (without
sinus drainage)
No neurological deficit
Neurological deficit secondary
to venous congestion
Assess venous phase of angiogram
Interruption of feeding arteries only
(endovascular transarterial or surgical
Refluxing cortical vein not
used for drainage of brain
Refluxing cortical vein used
for drainage of brain
CVR disconnection
(endovascular transvenous
or surgical)
Interruption of arterial
feeders only
(endovascular
transarterial or surgical)
Transverse/Sigmoid Sinus dAVFs
- Most common (40-60%)
Arterial Supply
ECA (occipital, posterior auricular , MMA,
ascending pharyngeal)
VA (posterior meningeal branch)
ICA (meningohypophyseal trunk)
Petrous bone
Venous drainage
Ipsilateral or contralateral sinus (if
thrombosed)
Cortical veins (temporal, occipital,
cerebellar)
Transverse/Sigmoid dAVFs
CVR:
Complete
excision:
• Dural
Drill flap
bonebased
laterally
on sinus
(mastoid & petrous) to expose sigmoid
• Disconnect
sinus (anterolateral
ALL arterialized
dura)
• veins
Dura incision above & below TS (medial to lateral)
•
Occlude & cut TS medially
•
Expose and cut tentorium
•
Extend to junction
•
Evaluate venous anatomy (Labbe, sigmoid sinus patency)
Cavernous Sinus fistulas
Barrow et al classification of carotid-cavernous fistulas
Type Feeding arteries
A
Direct fistula between ICA & CS
B
ICA meningeal br.
C
ECA meningeal br.
D
ICA + ECA meningeal br.
Spontaneous
Resolution?
High-flow
No
Low-flow
Yes
…presented next week…
Anterior Cranial Fossa dAVFs
• Arterial supply: anterior and posterior ethmoidal a.
• Venous drainage: ALWAYS cortical veins (frontal, olfactory)
• Aggressive lesions
• Treatment: Surgery (unilateral frontal or bifrontal craniotomy)
• !Embolisation  risk of central retinal artery occlusion
Convexity dAVFs
• Arterial supply: MMA
• Venous drainage: SSS +/- CVR
• Treatment: Surgery
• Other options for high-flow fistula into SSS (without CVR) associated with
papilledema:
• LP shunt
• Optic nerve sheath decompression
Deep venous dAVFs
• Arterial supply: ECA, ICA, VA, PCAs (tentorial dural branches)
• ?Hypertrophic dural arteries (including Bernasconi, Davidoff)
• Venous drainage: Rosenthal, LMVs, Galen
• Aggressive lesions
• If drainage into LMV  quadriparesis
• Treatment: Surgery (CVR disconnection)
Superior petrosal sinus dAVFs
• Arterial supply: ECA, ICA, vertebrobasilar (dural branches)
• Venous drainage: Usually (94%) CVR with SPS thrombosis
• Presentation:
• ICH 50%
• Ocular symptoms (w/ reflux into CS & SOV)
• Trigeminal neuralgia
• Treatment: Surgery (subtemporal craniotomy, posterior
petrosectomy, suboccipital craniotomy)
• Aim for CVR disconnection
Inferior petrosal sinus dAVFs
• Arterial supply: Vertebrtal a., ECA (ascending pharyngeal, MMA,
occipital)
• Venous drainage:
• Retrograde to IPS  CS
• Jugular bulb (tinnitus)
• Retrograde to transverse/sigmoid sinus
• Treatment: Surgery (far lateral approach)
• Aim at CVR disconnection
Results
• Van Dijk et al, Toronto, 2004:
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94.1% cure (25% endovascular, 25% surgical, 44% combined)
All complications transient (17.56% surgical, 4% endovascular)
No deaths or permanent neurological deficits
CVR disconnection equal to total excision
• Ambekar et al, Miami, 2015:
• 14.3% recurrence following endovascular treatment alone
• Baltsavias et al, Zurich, 2014:
• 85% complete occlusion following endovascular treatment alone
Thank you!