Surgical Pearl: The use of a laboratory vortex for poly-L-lactic acid injection

Abstract

P oly-L-lactic acid (PLLA) is a biodegradable, biocompatible synthetic polymer used for subcutaneous volume restoration. In 2004, PLLA gained Food and Drug Administration approval under the trade name Sculptra (Dermik Laboratories) for the treatment of facial fat loss associatedwithHIV infection. Sculptra is supplied as a carton containing two clear glass vials of a sterile freeze-dried preparation of PLLA microparticles combined with sodium carboxymethylcellulose, and nonpyrogenic mannitol. Injectable PLLA is typically reconstituted with 3 to 5 mL of sterile water. It is our practice to reconstitute with 3 mL of sterile water the night before the procedure and an additional 2 mL of plain lidocaine on the day of the procedure for a total 5 mL dilution. To fully hydrate the 40to 63m particles of PLLA into an even suspension, the manufacturer’s recommendation is to reconstitute the material at least 2 hours prior to use and vigorously agitate the material immediately before injection. Despite the use of appropriate techniques recommended by the manufacturer, one problem commonly observed with use of injectable PLLA is settling of the product out of suspension, both before and during the procedure. This is problematic for several reasons. First, the microparticles become trapped in the needle bore upon injection, resulting in frequent needle blockages and the need to change needles in mid-procedure. Second, settling of the material results in unequal concentrations of PLLA in a given syringe or vial, leading to the potential for asymmetry of volumetric correction following injection. This can be particularly problematic when one vial is split between the left and right sides of the