Package inserts for the Echelon, Marathon, and UltraFlow microcatheters from EV3 note that these devices are specifically “contraindicated for neonatal and pediatric use”. Since these microcatheters are needed to inject Onyx, these contraindications indicate that use of Onyx is not possible in neonatal or pediatric cases without violating this contraindication. Interestingly, the Onyx package insert does not state the same pediatric contraindication for Onyx itself. The microcatheter contraindications likely stem from bureaucratic regulatory processes, and, in fact, there is probably no evidence of any added risks specific to children. But if there ever was a complication in a pediatric case from injection of Onyx, the physician might have a difficult time explaining the situation. And based on the history of device-related medicolegal cases, it would probably be foolish to expect that EV3 would participate in the defense of a physician in such a case.