Download CEREBRAVASCULAR ANATOMY VENOUS

CEREBRAVASCULAR
ANATOMY VENOUS
SYSTEM&PATHOLOGIES
Eylül YERAL
• The cerebral venous system, unlike the majority of the rest of
the body, does not even remotely follow the cerebral arterial
system
• The cortical veins lie superficially, unlike cortical arteries, and
are adherent to the deep surface of the arachnoid so that they
keep the sulci open
• Cortical veins then drain to the nearest dural venous sinuses.
Such as the superior sagittal sinus and the straight sinus to
the the confluence of sinuses, then to the transverse sinuses,
sigmoid sinuses and internal jugular veins.
• The whole system may be divided into some sections:
• Cerebral Veins
• superficial
• deep
• Dural venous sinuses
• The cerebral veins drain the brain parenchyma and are
located in the subarachnoid space. They pierce the meninges
and drain further into the cranial venous sinuses.
• The cerebral veins lack muscular tissue and valves.
-superficial (cortical) cerebral veins
-deep (subependymal) cerebral veins
Superficial Venous System
• Comprised of the sagittal sinuses and cortical veins.
• The cortical veins course along the cortical sulci, drain the
cortex and some of the adjacent white matter.
• Can be subdivided into superior, middle and inferior groups.
• Important veins of superficial cerebral venous system;
-Superficial middle cerebral vein
-Superior anastomotic vein of Trolard
-Vein of Labbé
Superficial Middle Cerebral
Vein
• Runs along the lateral sulcus-also known as Sylvian Vein
• Drains into the sphenoparietal sinus or cavernous sinus
• Connected with superior sagittal sinus via great anastomotic
vein of Trolard, and with transverse sinus via posterior
anastomotic vein of Labbé.
Vein Of Labbé
• Largest channel that crosses the temporal lobe between the
Sylvian fissure and the transverse sinus
• Surgically it is of importance in planning temporal lobectomy
for refractory temporal epilepsy, as the vein should be
preserved, often requiring some cortical tissue to be left
behind. This is especially the case in the 10% of cases where
the vein is located anteriorly.
Deep Cerebral Veins
• Drain deeper parts of hemispheres, basal nuclei, internal
capsule, diencephalon and choroid plexus
• Consists of the lateral sinuses, sigmoid sinuses, straight sinus
and draining deep cerebral veins (subependymal and
medullary veins)
-Medullary veins are numerous and originate 1-2 cm below
cortical gray matter and pass through deep medullary white
matter and drain into subependymal veins.
-Subependymal veins receive medullary veins and aggregate
into greater tributaries, mainly into septal veins, thalamostriate
veins, internal cerebral veins, basal vein of Rosenthal and vein of
Galen.
Vein Of Galen
• Formed by the union of the two internal cerebral veins
and basal veins of Rosenthal
• Drain into the confluence of the inferior sagittal sinus and the
anterior extremity of the straight sinus
Vein Of Galen Malformation
• The most frequent arteriovenous malformation in neonates.
• Results from an aneurysmal malformation with an
arteriovenous shunting of blood
• Develops during weeks 6-11 of fetal development as a
persistent embryonic prosencephalic vein of Markowski
• Typically result in high-output congestive heart failure or may
present with developmental delay, hydrocephalus, and
seizures.(vary with the type of malformation)
• Has been associated with capillary malformationarteriovenous malformation (CM-AVM), which is a newly
recognized autosomal dominant disorder, caused by
mutations in the RASA1 gene in 6 families
• Presentation commonly with high output cardiac failure in neonates
while mostly hydrocephalus in infants and children
• Angiography:gold std
• Classification
- Lasjaunias classification:
 Choroidal: tend to present earlier (neonate) with more severe
shunts&high output cardiac failure
 Mural: present later (infant) and typically with hydrocephalus.
Fewer fistulas-high outflow restriction
-Yasargil Classification
 type I: small pure cisternal fistula between the vein of Galen and
either the pericallosal arteries (anterior or posterior) or posterior
cerebral artery
 type II: multiple fistulous communications between the vein of
Galen and the thalamoperforating vessels
 type III: high flow mixed type I and II
 type IV: parenchymal arteriovenous malformation (AVM) with
drainage into the vein of Galen
Tx&Prognosis
• Arterial feeder and fistula occlusion
• Transtorcular or transvenous embolisation of the dilated vein
• Prognosis is largely determined by the presence or absence of
cardiac failure. Thus choroidal types and those presenting in
the neonatal period do poorly.
Dural Venous Sinuses
• Venous channels located intracranially between the two layers
of dura mater (endosteal layer and meningeal layer)
• Unlike other veins in the body they run alone, not parallel to
arteries
• They are valveless, allowing for bidirectional blood flow in
intracranial veins.
• Together the dural venous sinuses form the major drainage
pathways from the brain, predominantly to the internal
jugular veins.
• https://www.youtube.com/watch?v=Dc-z7bDD-KM
Dural Venous Sinuses
Paired
•
•
•
•
•
•
•
transverse sinus
sigmoid sinus
superior petrosal sinus
inferior petrosal sinus
cavernous sinus
sphenoparietal sinus
basilar venous plexus
Unpaired
•
•
•
•
•
superior sagittal sinus
inferior sagittal sinus
straight sinus
occipital sinus
intercavernous sinus
Cavernous Sinuses
Located on either side of the pituitary fossa and body of
the sphenoid bone between the endosteal and meningeal layers
of the dura. (lateral and superior to the sphenoid sinus and are
immediately posterior to the optic chiasm)
• Boundaries:
Roof: fold of dura mater attached to the anterior and middle
clinoid processes
Anterior wall:medial end of the superior orbital fissure
Posterior:petrous apex
Medial: endosteum of body of the sphenoid bone
Lateral:dura mater from the ridge of the roof to the floor of
the middle cranial fossa
Floor: greater wing of sphenoid bone
Cavernous Sinus
• Receive venous blood from the facial veins (via the superior
and inferior ophthalmic veins) as well as the sphenoid and
middle cerebral veins(-inferior &superior petrosal sinusessigmoid-ijv)
• Because of this complex is made of valveless veins, blood can
flow in any direction depending on the prevailing pressure
gradients. Since the cavernous sinuses receive blood via this
distribution, infections of the face including the nose, tonsils,
and orbits can spread easily by this route.
Cavernous Sinus
Cavernous Sinus Thrombosis
• Rare, high mortality&morbidity
Etiology,
• Infections:
-Most commonly results from contiguous spread of infection
from the sinuses or middle third of the face(furuncle), or less
commonly dental abscess or orbital cellulitis
-Staph. Aureus (%55)
• Sinus compression, e.g. trauma, tumour
• Procoagulable conditions, e.g. Protein C/S deficiency, OCP use,
malignancy
• Idiopathic (25%)
• Headache(m.common)
• focal cranial nerve abnormalities
• periorbital edema and visual disturbances
Cavernous Malformations
• Mostly single lesions
• Multiple lesions may be familial and screening of family
members may be indicated (familial multiple cavernous
malformation syndrome)
• Along with capillary telangiectasias, are commonly seen
following cerebral radiotherapy
• Mostly asymptomatic- or hemorrhage and seizures
• Composed of a "mulberry-like" cluster of dilated thin-walled
capillaries, with surrounding hemosiderin.(Unlike AVMs,there
is no normal brain between the interstices of these lesions. )
• %80 supratentorial
• Characteristic popcorn appearance in MRI
• Symptomatic lesions should, when possible, be resected and
complete resection is curative
Cerebral Venous
Angioma(DVA)
• A congenital malformation of veins which drain normal brain
• Most common cerebral vascular malformation
• Characterised by the caput medusae sign(collection of dilated
medullary veins converge in an enlarged transcortical or
subependymal collector vein) in angiography. The appearance
has also been likened to a palm tree
• Usually incidental findings but patients can present
with intracranial haemorrhage(1-5%) and also with ischaemic
stroke and epilepsy.
• Most common location: frontoparietal region (36-64%)
• %75 solitory lesions but %20 of cases are associated
with cavernous malformations and are referred to as mixed
vascular malformations (MVM)
References
• Handbook of Neurosurgery (ebook), 7th Edition, by Mark S.
Greenberg
• https://radiopaedia.org/articles/vein-of-galen-aneurysmalmalformation-1
• http://www.dartmouth-hitchcock.org/cerebrovascular/veingalen-malformation-vog.html
• http://emedicine.medscape.com/article/1162804-overview
• https://www.medschool.lsuhsc.edu/neurosurgery/nervecente
r/icvensyspin.html
• https://www.ncbi.nlm.nih.gov/books/NBK27437/figure/A52/?
report=objectonly