INTRODUCTION
Fat transplants have been used in the aesthetic and reconstructive plastic surgery field for more than a century. In 1893, when Neuber first reported on using fat grafts to treat depressed scars, he concluded that fat specimens could not be bigger than an almond. Since that time, numerous surgeons from different medical specialties have utilized fat tissue in a great variety of pathologies.
Lexer used a block of fat tissue to correct a post-traumatic facial deformity and obtained an initial good result. In the long-term follow-up, he observed high rates of contraction and this fact inspired him to use bigger and bigger blocks of fat tissue. He never analyzed his grafts under the microscope. To improve the integration of fat grafts, May incorporated fascia to fat tissue grafts, and Peer chose to add the dermis to fat tissue. In 1957, Schorcher treated patients with hypomastia using multiple small fragments of fat tissue and observed a 75% loss rate in a 9-month follow-up. Ellenbogen developed the so-called ‘fat pearls’ with an average size of 8 × 5 mm. He used them in the eyelids and tear troughs, and experienced a 50% loss.
Because so many plastic surgeons have published unsatisfactory results with the use of fat grafts, this technique fell into disgrace for many years until Coleman’s first papers were published in the early 1990s. His results have given the plastic surgery community a new look at fat grafts. He discovered how to work with fat in a very systematic and reproducible way, which is called ‘lipostructure’, and has obtained much more favorable results.
In 1998, Lambros published some thoughts about retaining ligaments of the midface as latticework, and its relationship with skin and soft tissues, mainly the fat tissue. There is often a deflation component when the face ages, and this makes volume replacement necessary when rejuvenating a patient’s face. The zygomatic area and tear trough are anatomical sites where grafted fat tissue presents very good to excellent survival rates. Conversely, lips and nasolabial folds are the areas with the least graft integration rates.
Considering that fat tissue has been used as a filler, it might be assumed that it has many characteristics of an ideal filler ( Table 10.1 ), and only recently it has been adopted as the main source of adult mesenchymal stem cells.
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INDICATIONS AND CONTRAINDICATIONS
Fat tissue transplantation can be used whenever the main problem is soft tissue insufficiency caused by surgery, trauma, aging or pathology. In cosmetic surgeries, fat grafts can be used in post-liposuction deformities ( Fig. 10.1 ), in saucer deformity after gynecomastia surgery, and to reestablish, or simply add volume to, all facial areas such as zygomatic ( Fig. 10.2 ), mandibular, mental, temples, lips, nasolabial folds, eyebrows, eyelids, neck, tear troughs, face lifting deformities and acne scars. Cosmetic breast augmentation with fat is possible, but it is a very controversial issue. It deserves a closer evaluation and requires a great knowledge of adipose-derived stem cells (ADSCs) and their handling.
Fat transplants also have many applications in reconstructive surgeries, the most common of which are the Romberg’s syndrome ( Fig. 10.3 ) and other pathologies that present with lipodystrophy. Post-traumatic tissue loss in different areas of the body, defects following benign and malignant tumor resections, refinements in breast reconstruction, sequelae of facial paralysis, and sequelae of radiation therapy are all very common reasons for undergoing plastic surgery.
There are very few situations where fat tissue cannot be used. Extreme thinness is the most common contraindication because thin people do not have enough fat tissue to be harvested and grafted. Patients with poor general health are also not candidates for fat grafting.
PREOPERATIVE HISTORY AND CONSIDERATIONS
When a patient asks for some facial improvement, it is important to identify exactly what he/she is looking for, what his/her lifestyle is and how long the downtime period can be. Patients with high expectations are tricky, and the surgeon must thoroughly discuss the goals and limitations of the technique. It is also very important to take as many photographs as possible, from different angles and views, discuss with the patient where the problems are and demonstrate how they will be addressed by making drawings on the photographs. It is a good idea to ask patients to bring you old photographs. This can help you understand how they are aging and can give you clues about what a patient is looking for.
A patient’s medical history is a fundamental source of information about pathologies, blood clotting problems, allergies, current medications, previous surgeries and response to anesthesia. It is important to ask about previous cosmetic treatments: when, where, what product was injected, and how often? These questions can give you some information about the patient’s self-esteem and may suggest potential problems during fat graft delivery to the host tissue.
On physical examination, check skin quality and sensitivity, mimic musculature work and palpate the whole face in search for small nodules or blurred subcutaneous areas. This can help to identify areas treated with fillers that were missed during the clinical questionnaire.
Do not forget to prepare a good informed consent document with as much information as possible, including a note that a second procedure of fat transfer could be necessary because some absorption might occur. Fat grafts present some volumetric reduction until the sixth month and stabilize by the 12th month. Horl et al. demonstrated this phenomenon very well using magnetic resonance imaging.
OPERATIVE APPROACH
Structured fat grafting involves three important steps: harvesting, preparation and transfer. Fat tissue is obtained through small cannulas (2.5 mm in diameter × 15 cm in length) with two sequenced holes on the tip and under low negative pressure. The plunger of a 10 cm 3 Luer Lok syringe should be pulled back in 2 cm 3 increments. If general anesthesia is employed, a solution of ringer lactate and epinephrine in a final concentration of 1:500 000 is utilized and, if sedation is the option, a solution is made with lidocaine, bupivacaine, sodium bicarbonate, saline and epinephrine.
The abdomen is the preferred donor site. When different areas of the body are compared, some studies show no difference in adipocyte viability and survival rate after harvesting. Usually, the abdomen presents some localized fat and incisions can be placed inside the navel, leaving behind no stigma of surgery.
To optimize centrifugation, syringes full of fat are briefly decanted in a tube rack (Kartell, Labware Division, Noviglio, Italy) before they go into the centrifuge. Plungers are removed and a plastic plug seals the tip of the syringe while a silicone cork closes the upper part. The whole process of centrifugation is completely sterile.
After centrifugation (3000 rpm for 3 min), three well-separated layers are present. The top layer (least dense) is full of oil and cell debris, and the bottom layer is a mixture of blood and anesthetic solution. Both these layers must be discarded by aspirating the oil and draining the blood. The intermediate layer primarily consists of viable fat cells. To check the number of living cells, Boschert et al. specifically subdivided this layer into three parts and concluded that the part close to the bottom layer contained more adipocytes (in number) than the other two parts.
The middle layer is entirely transferred to 1 cm 3 Luer Lok syringes, through a Luer-to-Luer transfer, and grafting maneuvers are started. To do so, microcannulas (which means ‘a blunt tip’) of 1.0, 1.2 and 1.4 mm in diameter × 7 cm in length, with one hole on the tip, are employed. Multiple layers are done starting deep to the bone, passing through the muscles and ending close to the skin. If necessary, crossing tunnels can be made. The most important thing is to deliver small amounts of fat cells during withdrawal and, usually, to introduce a volume less than 0.1 cm 3 , in a radiating pattern during each pass. Needles are never used to graft fat tissue, and 3 cm 3 syringes are not used on the face.
To improve tear trough and lid–cheek junction, two portals are done. The first is located lateral to the orbit and approximately 1 cm below a horizontal line that passes at the level of the lateral canthus ( Fig. 10.4 ). The second one is placed at the meeting point of two lines – a vertical one that passes tangential to the lateral limbus and a horizontal one that passes at the level of the nostril sill. The latter portal is also utilized to graft the malar area. Because the portals are made with a 21G needle, there is no need for sutures and there is no scarring ( Figs 10.5 and 10.6 ).
