Fate of Free Fat Grafts with or without Adipogenic Adjuncts to Enhance Graft Outcomes

Sir: We read with great interest the article entitled “Fate of Free Fat Grafts with or without Adipogenic Adjuncts to Enhance Graft Outcomes” by Howard H. Tang et al.1 in Plastic and Reconstructive Surgery. The authors’ work on the fate of fat grafts is of vital importance and inspires us to explore better methods to improve viability of fat after fat grafting. In this study, human lipoaspirate alone or with Adipogel/stromal vascular fraction was implanted into the scalps of immunodeficient mice. According to the authors’ approach, the total volumes of each experimental group were 200, 400, 250, and 450 μl, respectively. In limited space under the scalp, the injected fat would be compressed in the recipient site.2 Different injection volumes were subjected to different compressing pressures from the scalp, which may adversely impact the capillary perfusion and, as a result, the viability of the graft.3 Thus, could it be more appropriate if the transplanted fat volume and total graft volume remained the same in different groups? If the pressure under scalps was too high, do we need to consider replacing the transplanted area, such as the flank? It is common practice to keep the total volume of injections consistent among experimental groups to eliminate the interference of pressure on the viability of adipocytes after transplantation, thus obtaining more reliable results. For example, in a study by Liu et al.4 regarding adipose stromal vascular fraction and platelet-rich fibrin on the outcome of autologous fat grafting, the authors made fat and total graft volume among groups consistent (adipose granules, 2 ml; total graft, 2.2 ml). DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication. Shengyang Jin, M.D.Facheng Li, M.D., Ph.D.Plastic Surgery HospitalChinese Academy of Medical Sciences andPeking Union Medical CollegeBeijing, People’s Republic of China