The Force Required to Inject a Column of Filler Through Facial Arteries

Injectable fillers have become an integral part of facial rejuvenation, but vascular occlusion is a dreaded complication of such injections.

To determine the force required by the fingertip onto the plunger of the syringe to cause retrograde migration.

In this cadaver study, twelve 2-cm arterial segments and 4 fillers were tested. Injection pressure required to force a column of filler for 1 cm was measured. Five oculoplastics specialists were subsequently recruited and asked to inject the filler at a typical injection pressure.

The nonhyaluronic acid filler required significantly more pressure to cause propagation of the material compared with all other fillers (p < .01). None of the other fillers differed significantly from each other. Typical injection pressures generated by experienced injectors were significantly lower than that required to cause propagation of filler at the desired velocity and significantly lower than mean arterial pressure. Measured pressure required to cause filler propagation was well within the normal range of the finger strength that can be generated by humans.

Typical injection pressures from fingertip to plunger are lower than required to cause propagation of filler intravascularly.