====== Vein of Galen malformation ======

also named [[Vein of Galen aneurysmal malformation]].Probably better termed as median prosencephalic arteriovenous fistulas.
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Vein of Galen malformations (VoGMs) are rare [[vascular malformation]]s resulting from persistent [[shunt]]ing of primitive choroidal vessels into the [[median prosencephalic vein]] of Markowski. VoGMs are associated with poor clinical outcome with a reported 76.7% mortality if left untreated
((https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5551915/#:~:text=Vein%20of%20Galen%20malformations%20(VoGMs,76.7%25%20mortality%20if%20left%20untreated.))
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Correct [[nomenclature]] can profoundly impact treatment; when we hear about a sexagenarian with a [[vein of Galen malformation]] we know the diagnosis is most likely a [[vein of Galen]] region [[DAVF]], with completely different ramifications. Other times we adopt new terms simply because they more accurately define the state, even though the older term is widely used and perhaps not quite inaccurate.

Rather than a [[brain arteriovenous malformation]] of the true [[vein of Galen]], VGAMs represent an [[arteriovenous fistula]] with drainage to a persistent embryonic vein, the [[median prosencephalic vein]] of Markowski
((Raybaud CA, Strother CM, Hald JK. Aneurysms of the vein of Galen: embryonic considerations and anatomical features relating to the pathogenesis of the malformation. Neuroradiology. 1989;31:109–128.)).

The vein of Galen aneurysmal malformation is a choroidal type of arteriovenous malformation involving the vein of Galen forerunner and is distinct from an arteriovenous malformation with venous drainage into a dilated, but already formed, vein of Galen.

[[Walter Edward Dandy]] can be credited with the first detailed description of the [[vein of Galen malformation]].

===== General information =====

Enlargement of the [[great cerebral vein]] of Galen (VOG) may occur in “vein of Galen malformations” (VOGM) (some refer to these as [[vein of Galen aneurysm]]s). Congenital, develop before the 3-month embryo stage or secondarily to high flow from adjacent deep parenchymatous AVMs or pial fistulae. Most likely consist not of the vein of Galen but rather of the  [[median prosencephalic vein]]. Parenchymatous AVMs can be distinguished from true VOG malformations by retrograde filling of the [[internal cerebral vein]] in the former
((Khayata MH, Casaco A, Wakhloo AK, et al. Vein of Galen malformations: intravascular techniques. In: Neurovascular Surgery. New York: McGraw-Hill; 1995:1029–1039))
True VOG malformations are predictably fed from the medial and lateral choroidal, circumferential, mesencephalic, anterior choroidal, pericallosal and meningeal arteries
((Khayata MH, Casaco A, Wakhloo AK, et al. Vein of Galen malformations: intravascular techniques. In: Neurovascular Surgery. New York: McGraw-Hill; 1995:1029–1039)),
((Lasjaunias P, Rodesch G, Pruvost P, et al. Treatment of vein of Galen aneurysmal malformation. J Neurosurg. 1989; 70:746–750))
[[Agenesis]] of the [[straight sinus]] may be an associated finding.


===== Classification =====

Classified based on the location of the fistula
((Yasargil MG. AVM of the brain, clinical considerations, general and specific operative techniques, surgical results, nonoperated cases, cavernous and venous angiomas, neuroanesthesia. In: Microneurosurgery. Stuttgart: Georg Thieme; 1988:317–396))
((Litvak J, Yahr MD, Ransohoff J. Aneurysms of the great vein of Galen and midline cerebral arteriovenous anomalies. J Neurosurg. 1960; 17:945–954)):

1. pure internal fistulae: single or multiple

2. fistulae between thalamoperforators and the VOG

3. mixed form: the most common

4. plexiform AVMs

===== Natural history =====

Untreated VOG malformations have a poor prognosis, with neonates having nearly 100% mortality, and 1–12 month olds having ≈ 60% mortality, 7% major morbidity, and 21% being normal
((Johnston IH, Whittle IR, Besser M, et al. Vein of Galen malformation: diagnosis and management. Neurosurgery. 1987; 20:747–758)).
Parenchymatous AVMs behave similarly to other AVMs.

===== Epidemiology =====
Vein of Galen aneurysmal malformations (VGAMs) are a group of congenital arteriovenous fistulas that comprise up to 37% of intracranial vascular lesions in the pediatric population
((Berenstein A, Ortiz R, Niimi Y, Elijovich L, Fifi J, Madrid M, Ghatan S, Molofsky W. Endovascular management of arteriovenous malformations and other intracranial arteriovenous shunts in neonates, infants, and children. Childs Nerv Syst. 2010;26:1345–1358.)).

United States

The incidence of the vein of Galen malformation is unknown.

International

The incidence of the vein of Galen malformation is unknown.
Mortality/Morbidity

Race

VGAM occurs in all races.
Sex

Boys and girls are affected equally.
Age

VGAM is a congenital malformation; therefore, it may present at birth or in early childhood.


Aneurysmal malformations of the vein of Galen (VGAM) typically result in high-output congestive heart failure or may present with developmental delay, hydrocephalus, and seizures
((Golombek SG, Ally S, Woolf PK. A newborn with cardiac failure secondary to a large vein of Galen malformation. South Med J. 2004 May. 97(5):516-8.)).

===== Clinical features =====

[[Vein of Galen malformation Clinical Features]].

===== Treatment =====

[[Vein of Galen Malformation Treatment]].


===== Complications =====

see [[Vein of Galen malformation complications]].

===== Outcome =====

VoGMs are associated with poor clinical outcome with a reported 76.7% mortality if left untreated. 


===== Case series =====

[[Vein of Galen Malformation Case Series]].

===== Case reports =====

[[Vein of Galen malformation case reports]]

===== References =====