Autologous fat injection for soft tissue augmentation in the face: a safe procedure?

Autologous fat injection for soft tissue augmentation in the face is claimed to be a safe procedure. However, there are several case reports in the literature where patients have suffered from acute visual loss and cerebral infarction following fat injections into the face. Acute visual loss after injection of various substances into the face is a well-known complication of such interventions. We report two further patients who suffered from ocular and cerebral embolism after fat injections into the face. For the intravasation of fat particles there are three preconditions: well-vascularized tissue, fragmentation of parenchyma, and, especially, a local increase in pressure in the affected tissue. Fat injections into the face lead to an acute local increase in pressure in highly vascularized tissue. We assume that fragments of fatty tissue reach ocular and cerebral arteries by reversed flow through branches of the carotid arteries after they are introduced into facial vessels. The manifestation of fat embolism appears either immediately after the fat injection or after a latency period. Fat embolism can remain subclinical and may not be recognized, or the clinical features may be misinterpreted. To minimize the risk of such a major complication, fat injections should be performed slowly, with the lowest possible force. One should avoid fat injections into pretraumatized soft tissue, for example, after rhytidectomy, because the risk of intravasation of fat particles may be higher. Metabolic disturbances such as hyperlipidemia may also contribute to the clinical manifestation of fat embolism Routine funduscopic examinations after fat injections into the face could help to provide data for future estimation of the patient's general risk.