Long-term survival of free fat grafts in muscle: an experimental study in rats.

In this study, we showed both macroscopically and microscopically the viability of the autotransplanted fat placed intramuscularly in long-term follow-up. The study was performed on 120 Wistar rats during a 12-month period. The fat grafts were obtained from either the inguinal region or preurinary bladder cavity. Rats were divided into six groups. In group 1, the fat was injected in thin rolls in the frontal subcutaneous layer. In group 2, the fat was injected in thin rolls in the gluteus superficialis, biceps femoris, gastrocnemius, and semitendinosus muscles. In group 3, 6 mm x 2 mm fat strips were placed subcutaneously in the frontal region. In group 4, the same dimension of fat strips were placed in the gluteus superficialis and biceps femoris muscles. In group 5, large cystic spaces of fat were injected subcutaneously in the frontal region, and in group 6, large cystic spaces of fat were injected intramuscularly. Rats at 3, 6, 9, and 12 months after fat grafting were sacrificed in order to carry out the macroscopic observations. The results showed clinical and microscopic success in groups 2 and 4, and problems and failure with the remaining groups.