(1)
Neurosurgery Teaching Hospital, Baghdad, Iraq
This book contains some difficult questions marked with “ * “ sign.
- 1.
VGAMs
Definition, the FALSE answer is:
- A.
The anatomic landmark of a VGAM is the presence of multiple arteriovenous shunts draining into a dilated median prosencephalic vein.
- B.
True VGAM are mainly fed from the choroidal and other surrounding arteries.
- C.
Are defined as arteriovenous fistulas in the choroid fissure supplied by the choroidal arteries and draining to the dilated median prosencephalic vein.
- D.
Are defined as arteriovenous fistulas in the wall of a persistent embryonic vascular channel called the median prosencephalic vein.
- E.
The median prosencephalic vein is an embryonic vessel normally present at the adult stage.
- A.
The answer is E.
The median prosencephalic vein is an embryonic vessel normally absent at the adult stage.
- 2.
VGAMs
Definition, the FALSE answer is:
- A.
Represent only 1 % of all cerebral vascular malformations.
- B.
Represent up to 30 % of all pediatric vascular malformations.
- C.
The median prosencephalic vein develops at the sixth week of gestation.
- D.
The median prosencephalic vein of Markowski usually regresses during the 11th week of gestation.
- E.
The vein of Galen is formed by the confluence of the internal cerebral veins only.
- A.
The answer is E.
The vein of Galen is formed by the confluence of the internal cerebral veins and the basal vein of Rosenthal.
The median prosencephalic vein of Markowski usually regresses during the 11th week of gestation, and by 3 months of gestation, the posterior part of it joins the internal cerebral veins and basal veins to form the vein of Galen.
- 3.
Vein of Galen aneurysmal malformations (VGAMs)
Anatomy, the FALSE answer is:
- A.
The vein of Galen lies in the suprasellar cistern.
- B.
The vein of Galen drains the thalamus.
- C.
The vein of Galen drains the occipital lobes.
- D.
The vein of Galen drains the medial temporal lobes.
- E.
The vein of Galen drains the superior cerebellar vermis.
- A.
The answer is A.
The vein of Galen lies in the quadrigeminal cistern.
The structures drained by the vein of Galen include the thalamus, the medial temporal lobes, the occipital lobes, and the superior cerebellar vermis.
- 4.
VGAMs
Anatomy, vein of Galen normal venous tributaries, the FALSE answer is:
- A.
Veins from the ambient cistern
- B.
Veins from the corpus callosum cistern
- C.
Veins from the superior cerebellar cistern
- D.
Veins from the sylvian cistern
- E.
Veins from the velum interpositum cistern
- A.
The answer is D.
The vein of Galen receives veins from the ambient, corpus callosum and superior cerebellar cistern, as well as the velum interpositum cistern.
- 5.
VGAMs
Anatomy, VGAM main arterial feeders, the FALSE answer is:
- A.
The anterior choroidal arteries
- B.
The posterior choroidal arteries
- C.
The vertebral arteries
- D.
The pericallosal arteries
- E.
The thalamoperforating arteries
- A.
The answer is C.
The vertebral arteries are not usual feeders for VGAM although it usually receives feeders from both anterior and posterior circulations.
True VGAM are predictably fed from the choroidal, circumferential mesencephalic, pericallosal, and meningeal arteries.
- 6.
VGAMs
Yasargil classification, the FALSE answer is:
- A.
Type I is the most common type.
- B.
All types have pericallosal arteries, P3–P4 arteries, and choroidal arteries.
- C.
Perforators from posterior communicating arteries and P1 are absent in type I only.
- D.
A companion intrinsic thalamic or mesencephalic AVM is present in type IV only.
- E.
Internal cerebral veins, atrial vein, and mesencephalic veins are visualized on cerebral angiogram of type IV only.
- A.
The answer is A.
Type III is the most common type.
Yasargil classified based on the arterial supply pattern of the malformation.
The Yasargil classification is probably the most descriptive one so far proposed, with application toward open neurosurgery, whereas the Lasjaunias system is more applicable to endovascular approaches.
Yasargil classification of vein of Galen malformations:
Type I: Pure cisternal fistula between pericallosal arteries (anterior or posterior), posterior cerebral artery (P3–P4 and its branches), and the vein of Galen
Type II: Fistulous connections between the thalamoperforators (basilar and P1 segment) and the vein of Galen
Type III: Mixed form with characteristics of both type I and II lesions (high flow) (the most common type)
Type IV: Plexiform (parenchymal) AVM with one or more intrinsic niduses within the mesencephalon or thalamus with draining veins emptying into vein of Galen (also known as secondary type)
Type IVA: Pure plexiform nidus in the parenchyma of thalamus
Type IVB: Pure plexiform nidus in the parenchyma of mesencephalon
Type IVC: Nidus within the parenchyma combined with fistulous cisternal nidus (type I)
- 7.
VGAMs
Lasjaunias classification, choroidal type, the FALSE answer is:
- A.
Choroidal type is the most common type.
- B.
Choroidal type is the simplest type.
- C.
Choroidal multiple feeders include thalamoperforating, choroidal, and pericallosal arteries.
- D.
The feeders are located in the subarachnoid space and the choroidal fissure.
- E.
The feeders converge on a fistula site at the anterior aspect of median prosencephalic vein.
- A.
The answer is B.
Choroidal type is the more complex type as compared with the mural type.
- 8.
VGAMs
Lasjaunias classification, choroidal type, the FALSE answer is:
- A.
Clinically, this type is the most severe form of the disease.
- B.
Tend to present earlier (neonate) with more severe shunts.
- C.
Choroidal type results in high-output cardiac failure.
- D.
The multiple high-flow fistulas with less outflow restriction cause the high-output cardiac failure.
- E.
Lasjaunias choroidal type equals to Yasargil type I.
- A.
The answer is E.
Lasjaunias choroidal type equals to Yasargil type II.
- 9.
VGAMs
Lasjaunias classification, mural type, the FALSE answer is:
- A.
Fistulae in the subarachnoid space in the wall of the median prosencephalic vein.
- B.
Supply may be unilateral or bilateral.
- C.
Associated with dilation and enlargement of dural sinuses.
- D.
Associated with stenosis at the level of the jugular foramen.
- E.
Arterial feeders arise from the collicular or quadrigeminal arteries and/or the posterior choroidal arteries.
- A.
The answer is C.
Associated with the absence or stenosis of dural sinuses.
- 10.
VGAMs
Lasjaunias classification, mural type, the FALSE answer is:
- A.
Lasjaunias mural type equals to Yasargil type I.
- B.
The mural type presents with fewer fistulas and high outflow restriction.
- C.
The mural type is associated with stenotic and narrow median prosencephalic vein.
- D.
The mural type manifests later in infancy as macrocephaly, hydrocephalus, or failure to thrive.
- E.
Cardiac failure, if present, is mild and cardiomegaly may be asymptomatic.
- A.
The answer is C.
The mural type is associated with more severe dilation of median prosencephalic vein.
Lasjaunias proposed an angiographic classification depending on the number and origin of feeding arteries.
Lasjaunias classification of vein of Galen malformations:
Choroidal type:
Multiple feeders including thalamoperforating, choroidal, and pericallosal arteries are located in the subarachnoid space in the choroidal fissure.
Converge on a fistula site at the anterior aspect of median prosencephalic vein.
Tend to present earlier (neonate) with more severe shunts.
Clinically, this type is the most severe form of the disease.
This type of VGAM results in high-output cardiac failure because of multiple high-flow fistulas with less outflow restriction.
Type I, the choroidal type, is the most common and more complex type.
Mural type:
Fistulae in the subarachnoid space in the wall of the median prosencephalic vein.
Arterial feeders arise from the collicular or quadrigeminal arteries and/or the posterior choroidal arteries.
Supply may be unilateral or bilateral.
Associated with the absence or stenosis of dural sinuses.
Associated with stenosis at the level of the jugular foramen.
This type of VGAM presents with fewer fistulas with high outflow restriction.
Due to the smaller number of fistulas and more outflow obstruction, they are associated with more severe dilation of the median prosencephalic vein and manifest later in infancy as macrocephaly, hydrocephalus, or failure to thrive. Cardiac failure, if present, is mild and cardiomegaly may be asymptomatic.
New classification system proposed by Mortazavi et al.: proposed a new classification scoring system combining the previous ones and including the two most important parameters affecting outcomes reported so far: heart failure and age.
The distinctive difference of this system is inclusion of clinical symptoms and correlation to treatment. Note exclusion of AVM and inclusion of heart failure and age as important prognostic factors.Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
