Two routes the filler could take

• Retrograde flow from facial artery into common carotid artery, flowing to internal carotid artery. Only larger volumes of product would cause this.

• Through the ophthalmic artery via one of the three vessels in the orbit, the supratrochlear, supraorbital or lacrimal arteries. Once into the internal carotid supply, there is a close connection to the middle cerebral artery.

The likelihood of this happening is more related to the injection of fat as opposed to HA dermal filler, however several cases have been reported of both. With this said, the pathway of blockage would be as follows;

Middle cerebral artery to frontal, temporal and parietal lobes of the brain, filler would travel into the lobes and block vitally important vessels, thus causative of stroke symptoms.