Continuing medical education article — body contouring: Suction-assisted lipoplasty: Physics, optimization, and clinical verification

Learning Objectives: The reader is presumed to have a broad understanding of plastic surgical procedures and concepts. After studying this article, the participant should be able to: Understand the basic science/physics of the equipment used in suction-assisted lipoplasty (SAL), including the cannula, tubing, suction pump, and the forces that affect suction efficiency. Define the factors that determine design characteristics of SAL cannulas, such as port size, port number, cannula diameter, cannula length, tubing parameters, and suction machine factors. Describe the clinical applications of this information and the experimental results that determine which variables are clinically significant in SAL. Physicians may earn 1 CME credit by successfully completing the examination based on material covered in this article. The examination begins on page 247. ASAPS members can also complete this CME examination online by logging onto the ASAPS Members-Only Web site (http://www.surgery.org/members) and clicking on “Clinical Education” in the menu bar. Background: Although suction-assisted lipoplasty (SAL) has been clinically practiced for more than 25 years, comparatively little investigation into fundamental physics of the instrumentation used in the procedure has been conducted. Moreover, relatively little is known about the clinical impact or merit of the wide variety of instrumentation currently available. Objective: In this study, we examined the physics related to the various components of instrumentation used in lipoplasty, and developed means to optimize performance based on quantified bench and clinical data. Methods: The components used to construct a lipoplasty system (vacuum pump, suction tubing, suction canister, and suction cannula) were first evaluated using methods of bench experimentation. A selected set of components/parameters were then evaluated in a clinical setting, and the results were correlated to the bench data. The following design parameters were analyzed: for cannulas—shaft length, shaft internal diameter, port size/pattern, and venting; for tubing—length, internal diameter, and collapsibility; for canisters—volume, pull-down speed, gradation precision, and splash-related issues; and for vacuum pumps—vacuum level and flow rate. Results: Each of the system components can have a significant impact on the overall performance of the system. A simple calculation is presented that can be used to quantify the relative “resistance” and, therefore, speed of any selected cannula or tube. Port area is shown to be an important aspect of cannula design and clinical performance. Clinical data are shown to correlate reasonably with bench data, which imparts credibility to the bench data and provides a platform from which to extrapolate other bench data to the clinical setting. Conclusions: With clinical objectives in mind, guidelines and recommendations are presented, based on the data we collected, to optimize a lipoplasty system with regard to choices of the vacuum pump, suction tubing, and canister. With the ideal system in place, the cannula becomes the only remaining variable. Cannula properties and performance were also studied and are discussed in detail.