The physics of suction-assisted lipoplasty.

BACKGROUND Some medical equipment manufacturers and surgeons have asserted that certain types of cannulas and other components of liposuction systems enhance the efficiency of fat aspiration. OBJECTIVE A laboratory experiment was designed to evaluate the effect of each component of a standard liposuction system on the rate of fat aspiration. A clinical investigation of the effectiveness of a vented (Turbo) cannula versus that of a standard cannula was also undertaken. METHODS The equipment used for the experiment included cannulas of varying lengths and diameters, provided with different tip geometries, suction tubes of 2 diameters, graduated canisters, and a vacuum pump. Applesauce was used as a simulated aspirant because its consistency appears similar to that of a mixture of fat and infiltrate. The time required to aspirate 1500 mL of material, with the pump set at maximum vacuum and the temperature and barometric pressure held constant, was measured. RESULTS Aspiration rates for the laboratory experiment with Becker, Keel Cobra Accelerator III, and Mercedes tip geometries were similar. In general, clinical aspiration rates were significantly lower than the laboratory rates. A higher aspiration rate was obtained with the vented Turbo cannula than with the conventional cannula. CONCLUSIONS Cannula-tip geometry has a minimal effect on the rate of aspiration; however, use of a tip less than 4 mm in diameter can cause clogging with fibrous tissue and significantly decrease the rate of aspiration. Aspiration is directly proportional to cannula and suction-tubing diameter and inversely proportional to cannula and suction-tubing length. Vented cannulas can enhance aspirate flow and efficiency. Further research is needed to investigate the significance of the fat fragmentation process and the development of fluids to simulate infiltrate/fat solutions in laboratory experiments.