Viability and Particle Size of Fat Grafts Obtained with WAL and PAL Techniques

Abstract

Water jet-assisted liposuction (WAL) and power-assisted liposuction (PAL) are used for autologous fat grafting. This study analyses the viability and particle sizes of fat grafts obtained by these techniques. The WAL and PAL techniques were applied in 9 female patients in identical body regions. In order to analyse cell viability, fat grafts were tested via the WST-8 assay and DNA quantification immediately after liposuction. Furthermore, in order to determine particle size, an optically evaluable water-fat emulsion was analysed by macroscopic inspection and light microscopy. The WST-8 assay showed significantly lower extinction values (OD) for use of the WAL technique - corresponding to a lower metabolical activity - compared to PAL liposuction: WAL 1.85±0.56 OD, PAL 2.25±0.57 OD. The quotient of extinction values and cell DNA concentration determined by DNA quantification also indicated statistically significant differences between both systems of liposuction in favour of using power-assisted systems: WAL 0.061±0.023 OD/μg, PAL 0.083±0.029 OD/μg. On the other hand, microscopic and macroscopic analyses showed significantly greater diameters (d) for fat grafts obtained with the PAL technique than by WAL liposuction: dmakroWAL=0.8 mm and dmakroPAL=1.1 mm or, respectively, dmikroWAL 0.89 mm and dmikroPAL=0.93 mm. Power-assisted liposuction obtains fat grafts with a higher metabolical activity than water jet-assisted liposuction. A falsification of extinction values within the WST-8 assay due to diversity of the number of cells was eliminated by additionally implemented DNA quantification. According to the current scientific debate, the particle size of obtained fat grafts is also considered as an important criterion for the success of autologous fat grafting. For clinical use, one should favour techniques which provide the smallest and most viable fat grafts as possible. In our opinion, the significantly lower size of WAL particles compared to the higher viability of PAL grafts indicates a necessity of analysing viability as well as particle size in order to evaluate liposuction systems. Data solely about in vitro viability of fat grafts fail to offer a recommendation for the use of a specific technique.