Development of micro-injection as an innovative autologous fat graft technique: The use of adipose tissue as dermal filler.

Abstract

Autologous fat graft, by virtue of its volumetric qualities and its action on skin trophicity, can be considered as a gold standard implant. Current techniques do not allow very superficial or subdermal injections of adipose tissue. The authors report technical modifications that enable fat transfer through a 25-gauge cannula. The viability of grafted fat was assessed after subcutaneous injection on a murine model. Micro-fat grafting consists of harvesting fat tissue using a multiperforated cannula with holes of 1 mm. Fat tissue is refined as described by SR Coleman and transferred through a micro-cannula. Initially, human fat was first harvested using two different procedures: Coleman's technique and the modified harvesting technique. Preliminary comparative histologic analyses were performed. Sixteen nude mice received human fat tissue: one side was filled with 0.7 cc through a 17-G cannula using Coleman's technique, and the opposite side was grafted using smaller cannulae (20G, 23G and 25G) following the modified harvesting technique. Mice were euthanised at 12 weeks and skin biopsies were performed. Experimental fat grafts on mice were observed and analysed: macroscopically, the fat tissue of each side showed the same healthy aspect. Haematoxylin-eosin-saffron staining revealed intact adipocytes and anti-CD31 antibody immunohistochemical staining highlighted an abundant neo-vessel network. Fat graft obtained by the modified technique maintains a normal histologic structure. Fat injection with micro-cannulae extends the application of lipostructure to the superficial layers of the skin.