VP Shunt in Vein of Galen Malformation
Primary Recommendation
VP shunt placement should NOT be used as first-line treatment for hydrocephalus associated with vein of Galen malformation; endovascular embolization to restore hydrovenous balance is the preferred initial approach, with VP shunting reserved only for cases where embolization has failed or the patient is not a candidate for endovascular therapy. 1, 2
The Evidence Against Primary VP Shunting
The interventional neuroradiology literature demonstrates that VP shunting as first-line treatment carries severe risks in this specific population:
VP shunt placement in children with vein of Galen malformations is associated with a 70% complication rate, including status epilepticus (14%), intraventricular hemorrhage (33%), and subdural hematoma or hygroma (24%). 3
Additional catastrophic complications documented include venous infarction, malignant dystrophic calcification, worsening developmental delay, and rapid neurological deterioration leading to death. 1
The pathophysiology explains these poor outcomes: high venous pressure from the malformation creates abnormal hydrovenous dynamics that make CSF diversion dangerous by causing rapid pressure shifts and venous complications. 1, 2
The Correct Treatment Algorithm
Step 1: Endovascular Embolization First
Endovascular closure of the vein of Galen malformation should be performed first to reestablish normal hydrovenous dynamics, which often resolves the hydrocephalus without requiring CSF diversion. 1, 2
In 21% of hydrocephalus cases associated with vein of Galen malformations, high venous pressure is the sole cause, and these cases resolve completely with embolization alone. 2
One series demonstrated that after switching from VP shunting to embolization-first strategy, children were treated successfully without the severe complications previously seen with shunting. 2
Step 2: Determine Hydrocephalus Etiology
The etiology of hydrocephalus in vein of Galen malformation determines subsequent management:
High venous pressure alone (21% of cases): Embolization is curative; no shunt needed. 2
Obstructive hydrocephalus from mass effect (9% of cases): If hydrocephalus persists after embolization, endoscopic third ventriculostomy (ETV) is the preferred CSF diversion method. 4, 2
Post-hemorrhagic hydrocephalus (11% of cases): Temporary external ventricular drainage is preferred; if permanent diversion is required, use highest-pressure valve VP shunt. 2
Hydrocephalus ex vacuo from melting brain syndrome (7% of cases): No intervention required. 2
Step 3: When VP Shunt Is Necessary
If VP shunt placement becomes unavoidable after maximizing endovascular therapy:
Use medium-to-high pressure valves to minimize rapid pressure changes that precipitate hemorrhagic complications. 2, 3
Administer prophylactic anticonvulsants preoperatively given the 14% risk of status epilepticus. 3
Place frontal VP shunts rather than other locations. 3
Recognize that even with these precautions, complication rates remain unacceptably high at 70%. 3
Role of Endoscopic Third Ventriculostomy
ETV is emerging as the preferred CSF diversion method for obstructive hydrocephalus in vein of Galen malformations when embolization alone is insufficient. 4
Case reports demonstrate good outcomes with minimal surgical complications when ETV is used for obstructive hydrocephalus after partial embolization. 4
ETV avoids the catastrophic pressure-related complications seen with VP shunts in this population. 4
Critical Pitfalls to Avoid
Never place a VP shunt before attempting endovascular embolization unless the patient is actively deteriorating and not a candidate for embolization. 1, 2
Do not assume all hydrocephalus in vein of Galen malformations requires permanent CSF diversion; many cases resolve with embolization alone. 2
Do not use low-pressure shunt valves if VP shunting becomes necessary, as rapid pressure changes precipitate hemorrhagic complications. 2, 3
Recognize that the general pediatric hydrocephalus guidelines 5 do not apply to this specific pathology due to the unique hydrovenous dynamics. 1, 2