Fat grafting is a hot topic in plastic surgery. Over the past ten years, it has emerged from its dark ages in which it was viewed as unsuccessful and in disrepute. Historically, fat grafting in cosmetic surgery was completely unpredictable. The transferred fat would usually completely resorb and, if not, it left lumps and contour irregularities in its wake. The technology of how the fat was processed was as unique as many kitchen preparations and the science of how it should work was more theoretical than fact.
But the age of enlightenment has come to fat transfer. Considerable research efforts have been made in plastic surgery that has led to the widespread clinical use of fat grafting with improved volume retention results. This is particularly evidenced by the rollout of devices and machines to help with fat processing (cleaning and washing) and transfer. When you factor in that most fat sites in the body are invested with high numbers of stem cells, the interest in the science and expanded use of fat transplantation becomes more appealing.
The technology of clinical fat injection grafting is based on isolation and concentration. Prior to transfer the objective is to purify the fat graft and remove any extraneous fluid, effectively increasing the volume of viable cells that is being transferred. This is traditionally done through centrifugation or straining methods in an open system. Machine technology offers to do the same thing but in a closed system. The advantages of a closed system are less potential for contamination and a more standardized processing method.Whether an open or closed system is faster to process depends on the techniques and the device used.
My current open method is a common one and consists of a strainer to remove excess fluid by gravity, a Lactated Ringer’s solution wash and then manually placing it into syringes for injection. One of the current advantages of an open approach is the ability to add differing components to the graft. While it is unclear exactly what ‘stimulants’ may be beneficial for fat grafting, the concept is theoretically appealing.
Currently, I am using a mixture of PRP (a plate-rich concentrate) and Matrigel collagen matrix. The high concentration of growth factors in platelets, and that it is obtained and concentrated from the patient’s own blood, seems like a natural choice. At the worst it causes no harm and the potential stimulation of growth factors, such as PDGF (plate-derived growth factor), on stem cells is more than just theoretical. Matristem is a lyophilized porcine-derived extracellular matrix which comes in a powder form. Mixed in with the fat graft, it adds a potential source of collagen stimulation and matrix onto which cells may attach and proliferate. While neither one alone, and most certainly together, has not been proven to help with injected fat survival, it is easy to make a composite fat grafting mixture before placing it into syringes. Neither interferes in any way with the ease of fat injection through a needle.
The flip side of fat processing is that of the donor site. Which part of the human body has the best quality fat?Which donor site offers fat with higher numbers of stem cells? What type of fat will survive the best after transfer? The scientific answer is that no one knows. Convenience is the usual reason a fat donor site is used or one in which the patient most highly wants the fat reduced. Often times it is a simple matter of volume. The amount needed for augmentation requires a donor site that has two or three times the volume to provide due to loss in the processing and concentration method. In facial grafting due to the low volume needed, the number of donor options is considerable. For high volume fat transfers such as buttock augmentation, every donor site the patient has may need to be used. The by-product of that need is that they are also going to get a good liposuction reduction result.
Injected fat has many body uses from body contouring to facial rejuvenation. For the body, buttock augmentation and breast reconstruction (lumpectomy defects) are being widely done. Fat breast augmentations are being approached more cautiously but is gaining some momentum also. The other good body use is that of hand rejuvenation, using the injected fat to fill hollows between the extensor tendons and to camouflage prominent veins. The face continues to be a rich and diverse area for fat injections from lipoatrophy to rejuvenation through volume restoration.
The future of injected fat grafting is bright with continued refinements in technology a certainty. With these technologic improvements will come better clinical results and new clinical uses not yet envisioned.
Dr. Barry Eppley
Indianapolis Indiana