A comparative study on the cooling and lipolytic effects of plate and vacuum suction cryolipolysis applicator using simulation

Clinical and biological experiments are often used to evaluate the effectiveness of cryolipolysis, but experiments cannot obtain complete heat transfer characteristics of cryolipolysis to evaluate the advantages and disadvantages of cryolipolysis devices. The drawbacks of the experiment also include long cycles, high funding costs, and unpredictable risks. To evaluate the lipolytic effect of cryolipolysis more conveniently, efficiently, and safely, two common cryolipolysis models (plate and vacuum models) have been established. The simulation considers the influence of multiple factors (cooling temperature, blood perfusion and fat layer size) on the heat transfer characteristics and lipolytic effects of cryolipolysis (lipolytic percentage, thickness, volume and weight). The results indicate that when the cooling temperature decreases from 4 °C to −11 °C, the lipolytic effect of two models can be improved by 22.06% at most. When the blood perfusion rate is higher than 3.6 × 10−6 s−1 and increases, the lipolytic effects of two models reduced by 7.46% at most. After estimating the lipolytic effect of fat layers of different thicknesses or sizes, it can be found that the lipolytic percentages of plate and vacuum model are 7.67–22.15% and 28.99–40.73%, respectively. The study conclusion shows that a decrease in cooling temperature and blood perfusion rate can improve the lipolytic effect. The cooling performance and lipolytic effects of the vacuum model are better than plate model at the same cooling temperature. By considering the influence of dual factors, a more comprehensive understanding was gained that cryolipolysis is more suitable for improving the cooling characteristics and lipolytic effect of thicker fat, but the blood perfusion rate set below 4.2 × 10−4 s−1 is not suitable to estimate the actual effect.