The impact of liposuction cannula size on adipocyte viability.

Purpose: Autologous fat transfer ("fat grafting") is widely used in cosmetic and reconstructive surgery, but long-term outcomes remain inconsistent. Each step in the transfer process can cause mechanical damage to the graft tissue. In particular, liposuction breaks aspirated adipose tissue into distinct globules and subjects it to shear forces, both of which can impact subsequent fat graft viability. The optimal size of the liposuction cannula for use in fat grafting is not known. METHODS AND TECHNIQUES: Controlled lipoaspirate samples were collected from adult female patients undergoing elective liposuction of the abdomen and flanks with uniform aspiration pressure (-25 in Hg) and either a 3- or 5-mm standard blunt-tip liposuction cannula. Individual grafts of 1.00±(0.01) gram were prepared and injected into the bilateral flanks of nude mice with a 14-gauge catheter. After six weeks, these grafts were explanted and analyzed by weight and histology.

Results: At six weeks, fat lobules in the 5-mm group retained 25% more weight than those in the 3-mm group [mean (SD), 0.70 (0.07) vs 0.56 (0.09) g, n=24/group, P<0.01). Histologic analysis revealed more intact, nucleated adipocytes in the 5-mm group than in the 3-mm group [4.42 (0.92) vs 3.10 (0.56) on a 1-5 rating scale]. The 5-mm group exhibited both less infiltrate [1.58 (0.17) vs 3.13 (0.70)] and less fibrosis [1.67 (0.45) vs 3.13 (0.89)] than the 3-mm group.

Conclusions: In this controlled model of fat grafting with either a 5- or 3-mm aspiration cannula, the use of a larger aspiration cannula led to improved graft retention and quality. This finding has important implications for clinical applications of fat grafting.