DURAL ARTERIOVENOUS MALFORMATIONS

Issam A. Awad, MD, MSc, FACS, MA(hon)Issam A. Awad, MD, MSc, FACS, MA(hon)

Professor of NeurosurgeryProfessor of Neurosurgery

Evanston Northwestern HealthcareEvanston Northwestern Healthcare

Feinberg School of Medicine Feinberg School of Medicine

Northwestern University Northwestern University

Evanston, IllinoisEvanston, IllinoisQuickTime™ and aGraphics decompressor

are needed to see this picture.

Lesion Definition

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

Venous hypertension in dural leaflet

Dural sinus outflow restriction/occlusion

Retrograde (leptomeningeal) venous drainage

Secondary sequelae of parenchymal venous hypertension

DAVM Pathoetiology

Sinus occlusion (congenital or acquired)

Trauma (blunt, penetrating, surgical)

Hypercoagulable states (including neoplasia, inflammation, etc…)

Angiogenesis

DAVM Lesion Progression

Dural leaflet AV shunting Pachymeningeal arterial

recruitment Retrograde venous

drainage, variceal/aneurysmal change

DAVM Natural History 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

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 varicesAwad et al. 1989

DAVM Location and Aggressive Clinical Course

Awad et al. 1990

DAVM Classification: Location and Venous Drainage

Type Djindjian Cognard Borden

I Normal antegrade flow intodural sinus

Normal antegrade flow intodural sinus

Drains directly into venoussinus or meningeal vein

II Drainage into venous sinuswith reflux into adjacent sinusor cortical vein

a. Retrograde flow intosinus

b. Retrograde filling ofcortical veins only

c. Retrograde drainage intosinus and cortical veins

Drains into dural sinus ormeningeal veins with retrogradedrainage into subarachnoidveins.

III Drainage into cortical veinswith retrograde flow

Direct drainage into corticalveins with retrograde flow

Drains into subarachnoid veinswithout dural sinus or meningealinvolvement

IV Drainage into venous pouch(lake)

Direct drainage into corticalveins with venous ectasia >5mmand 3x larger than diameter ofdraining vein

V Drainage to spinalperimedullary veins

DAVM Management Strategies

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

Stereotactic navigation

(CTA Guidance) Skull base exposures Intraoperative angiography Intraoperative embolization Evoked potential monitoring

Cavernous sinus DAVMs 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

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

Silent clinically until aggressive neurologic symptoms

Difficult, risky to embolize

Relatively easy to treat surgically

Radiosurgery option

Tentorial Incisural DAVM 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

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

QuickTime™ and aVideo decompressor

are needed to see this picture.

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

Recurrence at edge of coil

Recurrence in wall of occluded sinus

Surgical excision & disconnection of coiled sinus segment

Clival, Foramen Magnum DAVM

Frequent caudal leptomeningeal venous drainage

Brainstem symptoms or myelopathy (masquerade as spinal DAVM)

Tx.-- embolization, surgical disconnection (transcondylar, presigmoid approaches)

DAVMs: A Strategic Approach

Understand lesion pathoanatomy

Screen and watch for aggressive features

Consider all management options, modalities, limitations, risks

Individualize treatment