Facial Fat Grafting Treatment & Management

Skin care regimens such as glycolic acid peels (minipeels) and at-home products such as glycolic acid lotions and Retin-A–type products are useful adjuncts for the treatment of facial aging. Other management options for the treatment of rhytides include traditional lifting procedures such as facelifts and brow lifts as well as chemical peels, laser resurfacing, and dermabrasion. Often these modalities can be used in conjunction with fat grafting. See eMedicine’s Plastic Surgery journal for articles on various lifting procedures.

The most important principle in the surgical management is the atraumatic transfer of fat. Trauma to fat in the process of harvesting or placing fat affects the survival of the graft. While a nonviable graft initially may appear to have corrected the problem, eventual resorption of the tissue negates the result. Any blood that remains in the harvested fat also facilitates rapid degradation of the transplanted lipograft. The 3 parts of the surgery are harvesting the graft, transferring the graft, and placing the graft.

• First, carefully mark the recipient site with the patient's agreement while he or she is in the upright position.
• Sterilely prepare and drape both the harvest site and the recipient site.

Harvest

• The technique is designed to harvest the fat in parcels of readily transferable size. Common donor sites include periumbilical, lumbar, and trochanteric areas; the thigh; and medial sites of the knee and arm.
• Use local anesthesia to anesthetize the site for a small stab incision. Through this incision, use a long syringe to introduce tumescent fluid for anesthesia of the region. The same site serves as the access for harvesting.
• The choice of tumescent fluid varies. A standard solution consists of 1 mg of epinephrine, 200 mg of lidocaine, and 5 mEq of sodium bicarbonate in 1 L of normal saline. Dosages of lidocaine up to 35 mg/kg can be used for the tumescent technique, although substantially less is required for simple fat harvesting.
• Following infiltration of the region to be harvested, use an aspiration cannula (eg, Mercedes) connected to a syringe. Alternatively, a 14-ga needle can be used, as this causes no reduction in survival of fat harvested. Suction by hand or with a mechanical vacuum. Use a gentle passing motion for aspiration. Small syringes are recommended to avoid creation of negative pressures greater than 1 atm. Increasing the power suction from -.5 atm to -.95 atm has been experimentally demonstrated to result in the breakage and vaporization of fat cells, destroying their ability to be successfully transplanted.^[9]
• For visible tarsal plates and tear-trough or nasojugal fold improvements, a combination of pearl fat grafting and sparse fat injection may provide optimal results. Pioneered by Ellenbogen, this technique employs small pearls (5-8 mm in diameter) excised from fat and placed in saline. These pearls are then stacked on top of each other through an incision in the depressed area.^[2] This technique is not useful for nasolabial folds, labiomandibular folds, or chin augmentation.

Transfer and purification

• Once harvesting is complete, the aspirate then is transferred sterilely through multiple syringes using the tulip connections to 1-mL tuberculin syringes. The liquid fraction of the graft is gently washed free of oil, lidocaine, and blood with this transfer.
• An alternative to gentle hand tipping is use of the centrifuge. Although Chajchir found that use of the centrifuge machine at high or low speed completely destroyed the adipose cells,^{[10, 11]} other groups have reported good results with use of the centrifuge. The aspirate divides into 3 layers. The top layer is free oil from ruptured fat cells. This layer is decanted or blotted gently. The bottom layer contains variable amounts of tumescent fluid and blood and is drained. The middle layer consists of fat cells for grafting. More vigorous washing or straining may damage the fragile cells and decrease the viability of the graft.
• Inspired by a yogurt concentration method used in Anatolia, Kuran had recent success transferring aspirated fat to a sterile cup dressed with gauze.^[12] Five washes of lactated Ringer's solution rinses local anesthetic solution and blood from the fat. The aspirate is left to dry and the concentrated product is transferred to small syringes. Most groups favor a closed technique for sterility issues, but no published data exist for higher risk of infections in open procedures. The advantage of open technique is the option that allows the surgeon to manipulate fat to produce a graft that is easier to inject.
• The choice of fluid for fat suspension is controversial. Most commonly, normal saline or lactated Ringer solution is used. Serum free culture medium is also available, although it is more expensive. Some groups advocate additives such as heparin, insulin, vitamin E, and nonsteroidal anabolic hormones. The contribution of lidocaine is also debatable.
• In anticipation of future lipografts, adipocytes may be frozen to -30°C and reused. A high number of viable cells exist even after defrosting. Slow freezing and thawing is the method of choice to retain the maximal number of live cells.

Placement

• Regional nerve blocks are the most useful because adequate anesthesia can be provided without obscuring the defect to be treated.
• The goal with any grafting procedure is to gently apply the graft to a well-vascularized bed to maximize graft take. Every part of the graft should be within 1.5 mm of living, vascularized tissue. If a large area is grafted, the central area, which is most removed from the blood supply, may not survive. Still, some clinical evidence shows good lipografting survival in some tissues that are not well-vascularized (ie, hemifacial hemiatrophy and posttraumatic scars).
• Creating small tracks for the grafts helps keep the grafted fat adherent to the recipient site. Keeping the tracks independent prevents the fat from leaking out of the tunnel. Also take care to avoid overfilling the track. Overfilling can adversely affect graft survival and graft location.
• Insert the cannula either over a bevel-tipped needle or through a 1-2–mm stab incision made by a No. 11 blade scalpel. Guide the needle or cannula superficially under the rhytid or scar and inject fat in a controlled method gently upon withdrawal. Slight overcorrection is important because some absorption of the liquid carrier occurs. Some groups recommend a 30% overcorrection.
• level of fat grafting varies with the structure being augmented. Fat is grafted from the deep layer to the superficial layer.
• Kuran's technique calls for injection in parallel and crossing directions and at subcutaneous, intramuscular, and supraperiosteal levels for malar, buccal, and mental areas. Injections are only made parallel to the line for wrinkles and nasolabial sulcus corrections.^[12]
• With lip augmentation, grafting near the mucosa increases the amount of vermilion show. Grafting near the white roll tightens perioral rhytides. Gatti describes injection of 3 mL into the upper lip and 4 mL into the lower lip, although much larger amounts have been reported.^[13]
• Serial injection may be performed at 3-month intervals. Generally, 3 procedures should be anticipated. Even distribution of the injection is crucial. Excess bulk in a particular area may isolate the fat in the central region from the new blood supply.

• Discourage massage and excessive facial animation immediately following fat grafting. These restrictions are to prevent migration of fat away from the desired areas of treatment.
• Compression dressings to prevent migration have been described; however, they are often difficult to maintain and probably add little to the final result. If the fat has been placed in an appropriate tunnel, minimal concern about migration should exist.
• Ice compresses are applied for 24-48 hours to minimize inflammation.

• Patients should be seen in the first week postoperatively to check the donor and recipient sites. Some edema and a minimal amount of bruising may be apparent; reassure patients.
• An additional follow-up appointment should be made for approximately 6-8 weeks. At this point, most of the edema has subsided, and early results can be assessed.
• If a repeat procedure is to be performed, a waiting period of 3 months is prudent to allow the first graft to revascularize and to allow any edema to resolve.

The major complications of fat grafting are undercorrection and overcorrection. Undercorrection can be the result of the placement of less than the required amount of fat or from the resorption of some of the graft.

Although placing too little fat obviously fails to correct the defect, increasing the amount of injected fat does not always prevent problems. Placing too much fat in a particular area can contribute to failure of revascularization of the graft. Graft necrosis may cause palpable irregularities and eventual disappearance of the grafted material. Graft migration is usually caused by infiltrating too much fat into a particular site. The graft either is forced into an undesirable area or succumbs to pressure and lack of blood supply.

When grafting scarred areas, the graft tends to move to the areas of least tension. Clumping of the graft also may occur. This may be a particular problem under thin skin. After 1 month, if clumping is still a problem, instruct the patient on how to perform scar massage.

Undercorrection is generally easier to treat than overcorrection. Additional fat may be grafted at a separate sitting to complete the correction. Removing excess graft is more difficult as the host tissue infiltrates into the graft.

Damage to underlying structures, particularly around the eye, is possible and generally is prevented using the blunt needle for infiltration. Coleman reported a case of parotid injury when grafting a scar adherent to the parotid. Sharp needles were used. Niechajev and Sevcuk reviewed complications and discovered 4 cases of unilateral blindness and 1 case of severe damage to the CNS.^[9] All of these cases involved treating glabellar frown lines with probable resultant fat embolism. Careful control of the injection to keep the fat in superficial areas as well as use of the blunt cannula should prevent these complications.

Edema usually is evident for 2 weeks after the procedure; however, as with any procedure, prolonged edema is possible and troubling to the patient.

Bleeding complications usually are limited to transient mild ecchymosis and are associated with the use of sharp needles for fat injection. Superficial ecchymosis tends to resorb rapidly. Small hematomas are more unusual and are associated with the use of sharp needles for graft placement.

Although rare, infections can occur wherever the skin envelope is violated. The most common source of infection is the oral mucosa.

Additionally, donor site scarring is a potential concern. Contour irregularities can result from overly aggressive harvesting in a small area.

The major questions regarding fat grafting are how much of the graft survives and for how long. Many groups have reported on the fate of grafted fat; however, solid quantitative results have been difficult to establish. In addition to the variations in technique of fat grafting, quantifying the results objectively has been nearly impossible. Biopsy of the areas has been performed but is not a palatable option in the cosmetic patient. Further, while histology may demonstrate the integration of the graft, the relative volume retained remains unknown.

Imaging studies, such as MRI, may yield information in a noninvasive manner; however, such studies are quite expensive and inconvenient for the patient. Also, many of these patients undergo additional procedures either simultaneously or at a later date, which may confound the results. Individual variation in aging is another uncontrollable factor, although many studies reporting poor long-term results have been published. Surgeons who routinely perform fat grafting counter that failure to maintain meticulous technique accounts for the shortcomings.

Two major theories describe the survival of grafted fat. Peer proposed the host cell replacement theory.^[14] Histiocytes phagocytize free fat and become adipocytes. This idea largely has been replaced by the cell survival theory. Circulation is restored to the grafted fat cells in a manner similar to the revascularization of a skin graft. In the first 4 days, host cells, such as polymorphonuclear leukocytes (PMNs), plasma cells, lymphocytes, and eosinophils, infiltrate the graft. Within the vessels of the graft, red and white blood cells are clumped. On or about the fourth day, neovascularization is evident. Histiocytes act only to remove fat from broken down, nonsurviving, or disrupted cells.

Chajchir et al performed biopsies on the sites of grafted fat at intervals. Three months after transfer, zones of cytosteatonecrosis, lipophagic granulomas, lymphocytes, adipocytes, giant multinucleated cells, and new vessels were found. At 6-8 months, the specimens were infiltrated heavily by PMNs in a fibrotic matrix, and, at 1 year, a large amount of connective tissue and fibrotic reaction was present. Some fat was still present, but the authors felt that the inflammatory reaction may contribute more to the long-term result.

The key points of the theory of fat survival are (1) fat is a dynamic tissue and (2) cells that suffer trauma lose more volume. Therefore, careful handling of the graft is critical. Scarring and the added bulk of reactive tissue may contribute to the anticipated result.

Moore et al reported on the effects of mechanical damage to fat cells harvested with syringe suction lipectomy versus excision with local anesthetics.^[15] The mechanical damage to tissue aspirated versus tissue that was excised was unchanged. Lidocaine inhibited the glucose metabolism and lipolysis of adipocytes in culture. The effect was maintained only for as long as the lidocaine was present.

Also, as Smahel reported, fat grafts, like other grafts, must be small enough to be revascularized but large enough to maintain structural integrity and some native blood vessels.^[16] When part of the graft is not revascularized, the fat becomes necrotic and is not simply resorbed but is broken up and removed by the cellular elements.

Outcomes of early studies yielded disappointing results.

A 1991 report by Ersek revealed a 3-year follow-up period of fat grafting that was disappointing; however, although the fat was harvested atraumatically using a blunt cannula and minimal vacuum, the fat was processed in a traumatic manner using a whisk and strainer.^[17] The range of fat resorption was reported at 20-90%. Cortese et al reported resorption of 75-98% of the graft, but some good results were obtained with multiple procedures.^[18]

The techniques of grafting fat have changed markedly since these studies were performed. Niechajev and Sevcuk reported long-term results of fat transplantation clinically and histologically.^[9] Fat harvested by low-power aspiration was used. Patients were overcorrected by approximately 50% at the time of the initial procedure. Only partial resorption had occurred 1.5-4.5 years postoperatively. The clinical impression was that 40-50% of the result was maintained long-term. Histologic sampling at 7-36 months revealed fat cells in an organized structure. Longer-lived specimens demonstrated more pronounced fibrosis and organized connective tissue. The size of the graft was demonstrated to increase with overall weight gain by the patient.

Bertossi reported on the histology of biopsy specimens from the upper lip of 99 patients.^[19] Upon examination, the structure of the transplanted adipocytes was well-preserved. In some areas, connective tissue was dense and organized; in other areas, adipocytes and reactive cells with increased vasculature were in higher abundance.

Coleman reported long-term success when the treated rhytid was compared with a control rhytid.^[20] Patients were monitored clinically with careful photographic controls for 6.5 years. However, ongoing aging and choice of control rhytid can affect the interpretation of results.

Clearly, the results depend on the technique used for the procedure and on the method of measuring results. Advances in digital photography will aid in long-term follow-up care and documentation. Presently, clinical impressions and patient satisfaction support the use of fat grafting in many different situations.

Fat grafting has become a popular procedure for facial reconstruction and rejuvenation. The long-term results remain debatable. Standardized digital photography may allow more precise quantification of long-term results in a noninvasive manner.

Fat grafting for breast enhancement remains a controversial issue. Clinical trials assessing the long-term efficacy and safety are currently underway. Concerns include the low survival rates of adipocytes after implantation and the difficulties in differentiating calcifications due to breast cancer from calcifications due to fat transfer.

Preliminary studies have suggested that fat injections may even be clinically effective in patients who experience the adverse effects of radiation and in patients with severe burns.^{[21, 22, 23]} The results are not only aesthetically pleasing but also appear to mimic the texture of skin better. Histologically, biopsy tissue shows neovascularization, increased collagen deposition, and dermal hyperplasia.^[22] These effects are thought to be influenced by a population of stem cells, residing in the stromal vascular fraction of lipoaspirate tissue, that are capable of differentiating into multiple tissue types.^{[24, 25, 26]}

Investigations regarding pharmacologic manipulation of the graft are underway. Some groups have tested agents such as insulinlike growth factor, basic fibroblast growth factor, and a selective B1 blocker to enhance the survival of lipograft in rats.

In addition, techniques for simplification of harvesting are being developed. The ability to grow cells in culture may allow for multiple grafting procedures with a single harvest. The results seem promising and may one day be used in human facial fat grafting.