Download DAVM Lecture 2005

DURAL ARTERIOVENOUS
MALFORMATIONS
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Issam A. Awad, MD, MSc, FACS, MA(hon)
Professor of Neurosurgery
Evanston Northwestern Healthcare
Feinberg School of Medicine
Northwestern University
Evanston, Illinois
Lesion Definition
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Plexiform arteriovenous
fistulae with the nidus of
AV shunting totally within
the dural leaflet
Fed by pachymeningeal
arteries or dural branches
of brain or scalp arteries
Drained by adjacent dural
sinuses, or retrograde
through leptomeningeal
veins
DAVM Pathoanatomy and
Pathophysiology
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Venous hypertension in
dural leaflet
Dural sinus outflow
restriction/occlusion
Retrograde
(leptomeningeal)
venous drainage
Secondary sequelae of
parenchymal venous
hypertension
DAVM Pathoetiology
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Sinus occlusion
(congenital or
acquired)
Trauma (blunt,
penetrating,
surgical)
Hypercoagulable
states (including
neoplasia,
inflammation, etc…)
Angiogenesis
DAVM Lesion Progression
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Dural leaflet AV shunting
Pachymeningeal arterial
recruitment
Retrograde venous
drainage,
variceal/aneurysmal
change
DAVM Natural History
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Clinical presentation related to
lesion location
Aggressive symptoms
(hemorrhage, focal neurologic
deficits, seizures, etc.) solely
related to leptomeningeal
venous drainage
Progression, spontaneous
resolution highly unpredictable
(cavernous sinus DAVMs
notable for spontaneous
resolution)
Galenic DAVM
Spontaneous Resolution
At Birth
At 1 Year
DAVM Symptoms: Lesion
Location and Pattern of Drainage
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Flow symptoms, cranial
neuropathy
Ocular or intracranial
hypertension
Focal neurologic
symptoms, myelopathy,
seizures *
Hemorrhage *
* Aggressive Symptoms
DAVM Features Associated with
Aggressive Neurologic Course
RETROGRADE LEPTOMENINGEAL
VENOUS DRAINAGE
Pial drainage, Galenic drainage, Venous varices
Awad et al. 1989
DAVM Location and
Aggressive Clinical Course
Awad et al. 1990
DAVM Classification: Location
and Venous Drainage
Type
Djindjian
Cognard
I
II
Normal antegrade flow into
dural sinus
Drainage into venous sinus
with reflux into adjacent sinus
or cortical vein
III
Drainage into cortical veins
with retrograde flow
Normal antegrade flow into
dural sinus
a. Retrograde flow into
sinus
b. Retrograde filling of
cortical veins only
c. Retrograde drainage into
sinus and cortical veins
Direct drainage into cortical
veins with retrograde flow
IV
Drainage into venous pouch
(lake)
V
Direct drainage into cortical
veins with venous ectasia >5mm
and 3x larger than diameter of
draining vein
Drainage to spinal
perimedullary veins
Borden
Drains directly into venous
sinus or meningeal vein
Drains into dural sinus or
meningeal veins with retrograde
drainage into subarachnoid
veins.
Drains into subarachnoid veins
without dural sinus or meningeal
involvement
DAVM Management
Strategies
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Expectant and
symptomatic treatment-surveillance for progression,
aggressive features
Transarterial embolization-- palliative, preparatory,
definitive (slow polymerization)
Transvenous embolization-- pathologic segment
Surgery-- disconnection of leptomeningeal venous
drainage, coagulation/excision/isolation of
pathologic dural leaflet/sinus segment
Stereotactic Radiosurgery-- 18-24 months delayed
effect (interval risk)
DAVM Surgical Adjuncts
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Stereotactic navigation
(CTA Guidance)
Skull base exposures
Intraoperative angiography
Intraoperative embolization
Evoked potential monitoring
Cavernous sinus DAVMs
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Painful ophthalmoplegia, red
eye, bruit, visual loss
Spontaneous resolution,
progression of eye symptoms,
development of cortical
(Sylvian) venous drainage
Tx-- transvenous obliteration
(endovascular, open),
transarterial preparation,
radiosurgery, open surgery for
leptomeningeal venous
drainage or access to
cavernous sinus
Cavernous Sinus DAVM: Surgical
Access for Transvenous Obliteration
Superior Sagittal Sinus,
Torcular DAVM
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Venous outflow
obstruction,
papilledema
Cortical venous
drainage, focal
symptoms, hemorrhage
Tx.-- transarterial
embolization, surgical
disconnection,
radiosurgery, palliative
tx. of papilledema
CSF diversion
& radiosurgery
Surgical
disconnection
Superior Sagittal Sinus DAVM:
Preparatory Transarterial Embolization
and Surgical Disconnection
Transarterial embolization
Surgical disconnection
Anterior Falx (Ethmoidal)
DAVM
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Silent clinically until
aggressive
neurologic
symptoms
Difficult, risky to
embolize
Relatively easy to
treat surgically
Radiosurgery option
Tentorial Incisural DAVM
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Silent clinically or
neighborhood symptoms
(tic, bruit, etc.)
High frequency of
aggressive neurologic
symptoms (Galenic
drainage)
Difficult to cure with
embolization alone
Open surgery effective,
subtemporal or pre-sigmoid
transpetrous approach
Radiosurgery option
Transverse-Sigmoid (Lateral
Tentorial) DAVM
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Often presents with
bruit as only initial
symptom
Natural course
dependant on
leptomeningeal
venous drainage
Treatment options
individualized
CTA Guided Stereotactic
Disconnection of Transverse Sinus
DAVM
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Transverse-Sigmoid DAVM: Palliative
Embolization and Radiosurgery
Transverse-Sigmoid (Petrosal) DAVM:
Unusual “Cure” with Transarterial
Embolization Alone
Glue embolization
with slow
polymerization
Transverse-Sigmoid (Petrosal) DAVM:
Recanalization after Transvenous
embolization
Surgical excision & disconnection
of coiled sinus segment
Recurrence at edge of coil
Recurrence in wall of occluded sinus
Clival, Foramen Magnum
DAVM
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Frequent caudal
leptomeningeal venous
drainage
Brainstem symptoms or
myelopathy (masquerade
as spinal DAVM)
Tx.-- embolization,
surgical disconnection
(transcondylar, presigmoid
approaches)
DAVMs: A Strategic Approach
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Understand lesion
pathoanatomy
Screen and watch for
aggressive features
Consider all
management options,
modalities,
limitations, risks
Individualize
treatment