A Randomized, Prospective, Time-and-Motion Study Comparing Rate of Processing Techniques in Autologous Fat Grafting

Background: Autologous fat grafting (AFG) is increasing in popularity to address a variety of defects. As the number of cases each year increases, there is interest in developing techniques to harvest, process and inject fat, which should improve clinical outcomes as well as operative efficiency. The purpose of this study is to compare the rate of graft processing of three commonly used systems for graft preparation.

Methods: We conducted a prospective, randomized comparison of three methods to prepare adipose tissue for AFG: a passive washing and filtration system (Cytori PureGraft ^TM , system–PF), an active washing and filtration system (Revolve ^TM , system–AF) or centrifugation without filtration (Coleman technique, C). Processing technique was randomized by patient and stratified by four surgeons participating in the study. A trained, independent observer recorded the details of each procedure according to a behavioral checklist for the study. The primary outcome measure was rate of adipose tissue processed, defined as milliliters per minute. Secondary outcomes included total fat grafting time and total operative time. Additionally, the percentage of “graftable” fat, defined as the ratio of the volume of graft after processing relative to the volume input to the system was included as an exploratory measure.  

Results: Forty-six patients were included in the study (15 per study group, 1 was included with intention to treat after failed screen). The mean age was 54 years (SD 10 y) and mean BMI was 28.6 kg/m² (SD 4.13 kg/m²). There were no significant differences in patient characteristics or demographics between the three groups. Overall, the rate of adipose tissue preparation was significantly different among the three processing systems (AF 9.98 ml/min versus PF 5.66 ml/min versus C 2.47 ml/min, p≤0.0001). More specifically, the rate of adipose tissue preparation with system-AF was significantly higher than system–PF (difference = 4.32 ml/min, p=0.0014) or system-C (difference = 7.51 ml/min, p<0.0001). The rate of adipose tissue preparation with system-PF was significantly higher than centrifugation-C (difference = 3.19ml/min, p<0.001). Similarly, there was a significant difference in total grafting time between AF vs PF and AF vs C (AF=82.7±8.51 min versus PF=152±13.1 min p=0.0005, versus C=209.9±28.5 min, p=0.0005); however, there was no difference in total operative time between the systems (p=0.82, 0.60). The percent of graftable fat was higher with the active system compared to the passive system and centrifugation (AF=71% versus PF=39%, p=0.0001 versus C=43%, p=0.0001).

Conclusions: The results of this study indicate that an active fat graft processing system is more time efficient at graft preparation than a passive fat graft processing system or centrifugation without filtration. Time-and-motion studies such as this provide a reliable methodology to quantify efficiency and establish recommendations for best practices in fat grafting procedures.