Autologous fat transfer has been used surgically for a century and for a quarter of a century using lipoaspirate. More recently, techniques have focused on maintaining adipocyte viability by minimizing trauma, resulting in increased graph survival.1-4 This paper introduces the concept of cell-assisted fat transfer, a complementary approach that augments gentle harvest and implantation techniques with adipose derived mesenchymal stem cells (ADSCs) and growth factors from platelet rich plasma (PRP).
Stem cells have the characteristics of both replicating themselves and differentiating into a variety of other cells. Embryonic stem cells are found in the blastocyst 5 to 6 days post fertilization and are truly pluripotent, meaning that they can differentiate into any type of mature cell. These cells require sterile culture, tissue expansion, and differentiation prior to any therapeutic use and the usage of embryonic stem cells remains controversial on a bioethical level. Conversely, adult mesenchymal stem cells are found in many tissues, including bone marrow and adipose tissue,5 and are multipotent, meaning that they can differentiate into many different cell types, including vascular tissue, bone, cartilage, and fat. In addition to their cellular regenerative potential, they also exhibit chemotaxis and the ability to modulate inflammation.6-8
Adipose tissue is a rich source of adult stem cells – as much as 500 times the concentration found in bone marrow. Subcutaneous fat is a source of both the adipocytes and ADSCs used in this procedure. ADSCs are available in large quantities and can be harvested in a simple procedure under local anesthesia.9,10 The growth factors: epithelial growth factor (EGF), platelet derived growth factor (PDGF), transforming growth factor beta (TGF-beta), vascular endothelial growth factor (VEGF), and fibroblast growth factor (FGF) are present in increased concentrations in the platelet rich fraction of plasma obtained from peripheral blood.
Among the changes of aging and environmental damage seen in the face are loss of volume of both fat and bone, decreased collagen with the impairment of light reflex (brightness), skin laxity, and surface irregularities. With the exception of laxity, all of these changes can be addressed with cell-assisted facial fat transfer.10,11 Figures 1 and 2 illustrate the improvements achievable with cell-assisted facial fat transfer.
Figure 1. 59-Year-Old Male Before (left) and After (right) Undergoing Cell-Assisted Facial Fat Transfer
Figure 2. 47-Year-Old Female Before (left) and After (right) Undergoing Cell-Assisted Facial Fat Transfer
CELL-ASSISTED FACIAL FAT TRANSFER
Technique
Autologous fat transfer has been limited by the viability of the grafted adipocytes. Both graft and host issues contribute to this. Graft issues include both the harvesting technique and implantation technique. Host issues include the presence of systemic inflammatory disease and small vessel integrity, including the use of vasoconstrictors such as decongestants and nicotine.
Fat harvesting is performed by a “mini lipo procedure” designed to minimize trauma to the fragile adipocytes. First, a suitable area of subcutaneous fat is anesthetized using a tumescent technique with 0.05-0.10 lidocaine plus 1:1,000,000 epinephrine. The fat is extracted using: 1) gentle suction in the range of one half atmosphere (15-18 inches mercury or 350-370 mm mercury), 2) blunt cannula designed to minimize trauma, 3) decreased exposure to air, 4) low G-force (50 G) centrifugation or gravity density separation and 5) removal of free lipid. Each of these interventions has the aim of preserving the lobular architecture of adipocytes and optimizing graft survival. Equally important is preparing the host tissues by minimizing nicotine and other toxins and by optimizing nutrition.
The ADSCs are obtained by processing a portion (60-100 mL) of harvested adipocytes by incubating with an enzyme and then separating the stromal vascular fraction (SVF) with centrifugation. The SVF also contains pre-adipoctyes, endothelial cells, smooth muscle cells, fibroblasts, NK cells, endothelial progenitor cells, and growth factors.
The third component of the autologous “mixture” to be transplanted is the platelet rich portion of plasma. This is obtained by double centrifugation of a sample of the patient’s peripheral blood. PRP has increased quantities of multiple growth factors including EGF, PDGF, TGF-beta, VEGF, and FGF. The three components are then combined by gentle mixing prior to re-implantation.
Transplantation
Candidates
Candidates for this procedure include patients who would benefit from restored volume, those who want a natural filler, and those who want a longer lasting effect than is available from hyaluronic acids. The patient with minimal laxity, who is a healthy non-smoker, will likely have the best results.
Pre-Op Consultation
During the pre-op consultation the physician should first understand what the patient expects. This can be facilitated by using pre/post operation photos of the physician’s previous patients and the patient’s own pictures from previous years. These can be compared to contemporary photos and can guide both the physician and patient towards seeing the desired end result. The patient should be prepared for a recovery of five to seven days social downtime and be aware that a final result will not be apparent for several months. Platelet inhibiting agents should be discontinued secondary to both the increase risk of both bleeding and bruising and also the potential decrease of platelet growth factors release.
Anesthesia
Autologous fat transfer is a minimally invasive procedure and requires adequate anesthesia for the patient’s comfort and cooperation. Regional nerve blocks in the supraorbital, infraorbital, and mental areas as well as limited local anesthesia plus or minus oral lorezapram and distracting conversation will accomplish this is in almost all patients. Both general anesthesia and the supine position distort normal anatomy and should be used sparingly.
Implantation
Newly transplanted adipocytes must establish a blood supply to engraft. This is facilitated by proper harvesting that retains lobular structure and by implantation in the form of “micro-droplets” (0.025-0.05 mL). These micro-droplets are deposited with retrograde technique, from several directions, to obtain a crisscrossing pattern, and should be injected into multiple tissue planes. The placement should be consistent with aesthetic principles and to achieve the closest approximation to the patient’s expectations.
Post-Op Care
The patient is instructed not to use anti-inflammatory agents for at least 48 hours. Pain can be managed with acetaminophen plus or minus hydrocodone. Cool packs and sleeping with the head elevated will minimize post operation edema.
Complications
Complications include infection, bleeding, introduction of a foreign body, and nerve injury. The most common complication, however, is under or over correction resulting in a less satisfied patient.
Legal
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