Vein of Galen Abnormalities

This chapter discusses the various aspects of vein of Galen malformation (VGM). VGM is a congenital lesion in which intracranial arteries abnormally communicate with the median prosencephalic vein of Markowski, the developmental forerunner of the vein of Galen. The VGM is quite rare, representing less than 1% of all arteriovenous malformations, though its incidence is relatively higher in the pediatric group. The arterial supply to the VGM can originate in the carotid or basilar arteries and may be uni- or bilateral. Common sources include the anterior and posterior choroidal, pericallosal, anterior and posterior thalamoperforating, middle and posterior cerebral, and lenticulostriate arteries. A lesion that may secondarily enlarge the vein of Galen and leads to diagnostic difficulty is a dural arteriovenous fistula involving the falx of tentorium. Endovascular treatment has significantly improved the outlook. Without treatment, this was a uniformly fatal disease for neonates presenting in congestive heart failure, and the prognosis for older patients was better, but still dismal. It is found that with surgery, mortality ranged between 33 and 91%, depending on the age of the patient. It is observed that endovascular therapy has decreased this mortality to 0–40% depending on patient age.