Step 2.1

For small volume lipofilling, authors agree with the propagators of centrifugation rather than decantation. Centrifugation of the lipoaspirate results in three fractions: Hyperdense fat, hypodense fat, and waste (Figure 2). The hyperdense fat is rich in precursor fat cells, called adipose-derived stem cells (ADSC)21. These precursor cells seem to play an import role in vascularising the fat graft22, and could explain the regenerative properties12,23 of fat grafting. By using the high-density fat, and discarding the low-density fraction, we are in fact upgrading the lipoaspirate in comparison to a decanted sample14,24. In theory, high-density fat grafts show a higher percentage of graft retention, and have superior ‘regenerative’ potential over low-density fat grafts25. The senior author tends to use high density fat for superficial ‘regenerative’ purposes, and low density fat for deep lipofilling, which focuses more on volume.

Step 2.2

One round of centrifugation (2.5 minutes) only yields 6‑times 3–6 cc of viable lipograft, reconstructions requiring a large volume of lipograft, such as those for the breasts or buttocks, would be too time-consuming using this method. A number of commercially available systems deliver an alternative method of harvesting and processing. These include water-assisted liposuction and the lipocollector26. The senior author has put a number of systems to the test, and prefers the Cytori Puregraft® 850 system (Cytori Therapeutics, San Diego, CA, US). This closed system cleans the lipoaspirate of oil, water, and infiltration fluids like adrenaline and lidocaine by osmotic washing. The result is a viable and clean lipoaspirate, with a similar or even superior quality in comparison to centrifuging, in only a fraction of the time27.

Step 2.3

Figure 3 A 26-year-old man with hemifacial atrophy, (A) preoperatively, and (B) 24 months postoperatively after 33 cc of lipofilling on the affected side

Figure 3 A 26-year-old man with hemifacial atrophy, (A) preoperatively, and (B) 24 months postoperatively after 33 cc of lipofilling on the affected side

The upgrading of lipoaspirates with a fraction of ADSC is a relatively new but promising technique. As discussed, the ADSCs seem to play a central role in fat graft survival14. In the first days after transplantation, the ADSC have a supporting role for the adipocyte, and later they play a key role in neoangiogenesis in the fat graft. Although promising, there are no large placebo-controlled human trials to date. There are a range of devices on the market that can extract ADSC from lipoaspirates, mainly by enzymatic breakdown. Unfortunately, these devices have a high cost and maintenance price, and processing of a lipoaspirate is time consuming. Another fact to take into account is the potential oncogenic potential of these grafts. The technique seems promising, but does require more study on both long-term safety and efficacy28.

Step 3.1

Injection of the fat should take place in a 3D fashion in the tissue layers, rather than just placing large lumps. Placement of the fat in a 3D fashion greatly expands the area over which diffusion can take place, which is the key factor in graft survival during the first days post-treatment. Another commonly accepted fact is that overfilling is counterproductive. Adding extra fat to a host area that is not capable of supporting it leads to less fat retention. Overfilling also increases the pressure in the lipofilling compartment, a finding that has been linked to a high percentage of graft loss29. It is better to build up volume in two or three separate sessions rather than overfilling in one session30.

Table 1

Step 3.2

Pre- and postoperative expansion of the lipofilling site seems to have a positive effect on survival, as shown by Khouri’s BRAVA system18. Compartment pressure is lowered by external suction, which in theory lowers liponecrosis. Furthermore, local expansion of the tissue increases vessel formation in the donor area. Pre-treating the donor area increased fat retention by 20%, which was determined through MRI scans. Results of the BRAVA system are exceptional (Figure 4); the only significant drawback of using this system is the high patient effort and compliance needed. The latest protocol suggests that patients should wear the brava system for at least 10 hours per day for 4 weeks before and after surgery.

Step 3.3

Platelet-rich plasma (PRP), used in orthopaedic medicine for decades31, has now made its introduction into plastic surgery. Adding a high concentration of platelets directly to the lipograft or injecting it in the host area will release a tremendous amount of growth factors. These growth factors are normally associated with wound healing, and in the case of vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF)32 are pro‑angiogenic. Although large prospective human studies are lacking to date, there are many promising placebo controlled animal studies that show an impressive effect. In the studies of Oh et al33 and Nakamura et al34, the authors observed significantly higher fat retention with increased vessel formation. The right concentration (4–5 times above baseline) of PRP seems paramount in achieving these effects35. How exactly PRP improves graft take remains unclear; the growth factors may influence the ADSC in the lipograft, the adipocyte, the donor area, or a combination of all. Clinically, there seems to be an effect that is further supported by the significant results described in the authors’ own retrospective studies (submitted) on aesthetic outcome and recovery time when using PRP.