The Operation for Vein of Galen Malformations in Children

Patient Positioning

• Supine positioning: The patient should be supine with the head toward the biplane imaging apparatus.
• Inability to achieve transarterial or transvenous access: In rare cases, the approach may involve direct puncture of the central venous sinuses (87). This may be required if there is no feasible arterial access (when the individual arterial pedicles are too small) and when transvenous access is limited by venous stenosis. The latter may be observed at the jugular bulb.

Surgical Approach

Treatment often follows a staged approach, with multiple procedures staged over 1 to a few weeks.

Transarterial approach

• Femoral artery access: Accessing the femoral artery may have greater success and less risk with ultrasound guidance. Although radial artery access is well-established as a viable alternative in adult neurointervention radiology, the first degree branch angles from the aorta in neonates and infants are typically unfavorable for transradial access. However, these branch angles are extremely favorable and safe for navigation from transfemoral access in neonates and infants.
• Transarterial approach: The guide catheter is advanced into the internal carotid artery or the vertebral artery. In children, intermediate catheters may often be directly applied as a guide catheter and simultaneously taken intracranially for distal support. The microcatheter is advanced over a microwire to access the desired arterial feeders (75).

Transvenous approach

• Transvenous approach: Femoral vein access or, less commonly, direct jugular vein access is achieved in combination with arterial access (77). The guide catheter is advanced into the internal jugular vein and the dural sinuses. Microcatheters are advanced into the falcine or straight sinus, and occasionally in a retrograde fashion into individual feeding arteries.

Intervention

• Endovascular embolization: Via the transarterial approach, embolic agents (coils and liquid embolic agents) are deployed in the feeding artery as close to the fistula as possible, aiming to reduce supply to the fistula while preserving normal flow to the brain parenchyma (75). The proximal draining vein can also be embolized via the transvenous approach; this may involve a combination of coils and liquid embolic agents (77).
• Limit contrast dose: Avoid contrast-induced nephrotoxicity by limiting contrast dosage to 7-10 mL/kg (60,78).
• Consider cumulative radiation dose: In all neurointerventional radiology — and particularly in children — accumulated radiation dose should be noted. Weigh the potential impacts when making decisions about diagnostic and guiding image acquisitions and the magnification level for fluoroscopic guidance. In embolization for VOGM, rotational angiography and 3D reconstruction of the malformation tend to require excess contrast load and to inadequately define the structure owing to its high flow and multiple arterial contributions. Therefore, these techniques are not routinely used.

Closure

• Hemostasis: Hemostasis can be achieved by manual compression. A compression bandage can be used in patients of adequate weight.
• Complications: In neonates, femoral ischemia is a serious complication that can occur even with common pressure dressings.