The Effect of Pressure and Shear on Autologous Fat Grafting

Sir: We read with plenty of interest the original article by Lee et al. entitled “The Effect of Pressure and Shear on Autologous Fat Grafting.”1 We congratulate the authors for the well-designed study investigating the impact of pressure and shear on adipocyte viability. We fully share the authors thinking on suction pressures achieved using the standard Coleman technique: in our research experience also, they are not low and atraumatic as is commonly thought. However, our data recently published in your Journal,2 although only investigating the immediate damage to mature adipocytes, appear to be very different from those exposed in the work by Lee et al. We can try to speculate on the reasons for this discrepancy. First, the authors claim to have quantified 3, 10, and 60 ml of suction pressure by a manometer, but all the pressures they detected appear to be virtually similar to each other, contrary to the values shown in another recent article by Rodriguez and Condé-Green.3 Second, they applied to a standard suction machine the pressure corresponding to different values of vacuum plunger pull-back, simulating in this way the pressure acting in syringes. However, this step seems to ignore the Poiseuille law: we know that in a duct of constant caliber, the pressure loss is inversely proportional to the length of the duct.4 Thus, the pressure value acting on lipoaspirate by manual harvesting with a syringe is absolutely not the same as that exerted by a liposuction machine (even if the external set value is similar) because there are at least 2 m of pipe between the machine and the site of liposuction, which drastically reduces the pressure. Finally, we completely agree with Kokai and Rubin,5 who reiterate how difficult it is to standardize procedures, as these are often dictated by surgical needs. However, at least in research methodologies, we should all attempt to minimize the number of different and compounded processing variables, aiming to better compare results across multiple studies. DISCLOSURE The authors have no financial interest to declare in relation to the content of this communciation. Damiano Tambasco, M.D. Department of Plastic and Reconstructive Surgery Catholic University of the Sacred Heart Rome, Italy Giorgio Netri, M.D. Private Practice Manchester, United Kingdom Maria Francesca Bianciardi Valassina, M.D. Private Practice Francesca Grussu, M.D. Daniele Cervelli, M.D., Ph.D. Department of Plastic and Reconstructive Surgery Catholic University of the Sacred Heart Rome, Italy