This article presents the authors’ 3-year experience with the use of fat grafting, via the Coleman technique, for the adjuvant treatment of burn wounds, venous ulcers, diabetic ulcers, and burn scars. It demonstrates the regenerative effects of fat injected under the scar, and of fat injected under the wound, in the periphery of the wound, and within a bone fracture line or space, and of fat deposited over the wound.
Key points
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The use of fat grafting has changed our practice dramatically, mainly in relation to our previous routines of using immediate excision and grafting in burns of the hands and in relation to our early (practically the immediate day after admission) use of muscle flaps for exposed bone fractures in patients who were traditionally referred (6–8 weeks after the original injury) from a local state hospital with subacute wounds and open fractures of the middle or lower third of the leg.
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Fat grafting has also greatly influenced the way we treat hypertrophic scars as a consequence of burn wounds.
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One of the most pleasant surprises in using fat grafts is the minimal incidence (or none) of hypertrophic scarring on the healing of wounds treated with one or more sessions of fat grafting.
Overview
Fat grafting has been used worldwide taking advantage of the benefits of adipose-derived stem cells (ADSC’s) for regenerative purposes and their ability to differentiate in fat, bone, cartilage, muscle, and possibly other tissues. They also have a great variety of regenerative and metabolic properties, and growth factors (eg, epidermal growth factor, transforming growth factor-β, hepatocyte growth factor, platelet-derived growth factor, basic fibroblast growth factor). Fat on the lipoaspirate can be isolated and/or treated by physical or chemical methods, in the operating room, or in a laboratory setup.
Burns and Wound Healing
The most typical burn that occurs in a child in our area of the world is a burn caused by hot liquids during preparation or consumption of a meal, followed by sudden flame of ethanol, used by the child or in the vicinity of an adult using ethanol.
In the adult population, most commonly burns are caused by ethanol, a work-related injury (electrical, hot surfaces, plastic extrusion/packaging machine, and so forth), or a motorcycle accident (contact burns with the exhaust system, or friction burn/fracture in a fall).
Because our burn service was founded in 1968, and it is open to all patients regardless of payment or insurance, in the past 46 years we have seen more than 320,000 burn cases. Thus, we have slowly evolved to become a burn and wound care center, receiving a substantial number of patients with subacute or chronic wounds, either in consequence of a motorcycle or motor vehicle accident, or related to vascular insufficiency or diabetes.
Patients who are candidates for fat grafting procedure at our service are those with (1) hypertrophic scars that are not improving or not being controlled by pressure garments at 6 or more weeks after healing, (2) burn wounds at 3 weeks or more with no apparent progression to healing, (3) subacute burn wounds or other wounds transferred to us within more than 6 weeks after the accident or wound, and (4) venous or diabetic ulcers.
Surgical Approach
In wounds, we use the Coleman technique, repeating injections (and reharvesting) every 2 to 4 weeks until healing or until a definite procedure (eg, wound closure, skin grafting, flap, or other) is performed. After healing, injections under the scar are performed at 3-month intervals, also via the Coleman technique. This approach is also taken with patients with scars who seek our service for consultation after being treated elsewhere.
Overview
Fat grafting has been used worldwide taking advantage of the benefits of adipose-derived stem cells (ADSC’s) for regenerative purposes and their ability to differentiate in fat, bone, cartilage, muscle, and possibly other tissues. They also have a great variety of regenerative and metabolic properties, and growth factors (eg, epidermal growth factor, transforming growth factor-β, hepatocyte growth factor, platelet-derived growth factor, basic fibroblast growth factor). Fat on the lipoaspirate can be isolated and/or treated by physical or chemical methods, in the operating room, or in a laboratory setup.
Burns and Wound Healing
The most typical burn that occurs in a child in our area of the world is a burn caused by hot liquids during preparation or consumption of a meal, followed by sudden flame of ethanol, used by the child or in the vicinity of an adult using ethanol.
In the adult population, most commonly burns are caused by ethanol, a work-related injury (electrical, hot surfaces, plastic extrusion/packaging machine, and so forth), or a motorcycle accident (contact burns with the exhaust system, or friction burn/fracture in a fall).
Because our burn service was founded in 1968, and it is open to all patients regardless of payment or insurance, in the past 46 years we have seen more than 320,000 burn cases. Thus, we have slowly evolved to become a burn and wound care center, receiving a substantial number of patients with subacute or chronic wounds, either in consequence of a motorcycle or motor vehicle accident, or related to vascular insufficiency or diabetes.
Patients who are candidates for fat grafting procedure at our service are those with (1) hypertrophic scars that are not improving or not being controlled by pressure garments at 6 or more weeks after healing, (2) burn wounds at 3 weeks or more with no apparent progression to healing, (3) subacute burn wounds or other wounds transferred to us within more than 6 weeks after the accident or wound, and (4) venous or diabetic ulcers.
Surgical Approach
In wounds, we use the Coleman technique, repeating injections (and reharvesting) every 2 to 4 weeks until healing or until a definite procedure (eg, wound closure, skin grafting, flap, or other) is performed. After healing, injections under the scar are performed at 3-month intervals, also via the Coleman technique. This approach is also taken with patients with scars who seek our service for consultation after being treated elsewhere.
Treatment goals and planned outcomes
The use of fat grafting as an adjuvant treatment in acute and subacute burn wounds and in chronic vascular wounds (venous insufficiency or diabetic arterial disease) takes advantage of fat’s benefits: a variety of metabolic and regenerative properties, increasing vascularization, and enhancing the tissue regeneration process. When these wounds are treated with repeated fat grafting (15–21 days apart), healing is the planned outcome.
When treating burn scars, the objective is to decrease the amount of hypertrophy (fibrosis), diminishing the scar thickness and increasing scar malleability. We also use this technique to decrease fibrosis around bone joints and at releasing tendon adhesions.
Preoperative planning and preparation
Patients with subacute burn wounds (more than 3 weeks in our Service without apparent progression to healing), open fractures of the tibia, associated to nonhealing or poorly healing wounds, chronic venous insufficiency, or diabetic arterial disease wounds are selected for adjuvant treatment with fat injection. In open wounds, injections are performed under general anesthesia, in 15- to 21-day intervals.
Patients with hypertrophic scarring after healing of a burn or keloids of any origin are also selected for treatment with fat injection. Repeat injections (up to four injections total) are performed at 8- to 12-week intervals.
Donor areas are “rotated” as needed and fat most frequently is obtained from the abdomen, thighs, or lateral upper buttocks. When necessary, shaving of the pubic area or proximal thigh is performed in the operating room, immediately before the procedure. Puncture incisions for introduction of the liposuction cannula are placed on the midline, at the suprapubic crease; medial to the femoral pulse, at the inguinal crease; or in the middle axillary line, at the upper border of the iliac bone.
The actual volume of harvested lipoaspirate should be at least twice the anticipated volume planned to be injected, and at least four times this volume if one is also planning to have fat deposited over the wound.
Procedural approach
Fat harvesting and fat injection are sterile surgical procedures and should be performed only in accredited operation rooms under rigorous, completely sterile technique. In patients with scars (healed wounds), the donor area and recipient area are individually prepared and draped in the usual manner. In patients with open, nonhealed wounds, the recipient area is prepared only after the planned amount of fat is obtained, while it is being centrifuged and distributed in various syringes.
Fat is harvested from the patient himself or herself, using a 10-mL Luer Lok syringe, attached to a 3-mm cannula, with two 3-mm side openings distally, with 10-, 15-, or 20-cm length, according to the harvesting site. In children weighing less than 25 kg, we prefer 20-mL syringes and multi (micro) perforated cannulas, which enforce a higher negative pressure ensuring more even and efficient fat harvesting, respectively. Occasionally, in very small patients (our smallest patient weighted 13 kg), it may be necessary to harvest fat from more than one donor site.
One or more distally plugged 10-mL syringes containing the obtained fat is centrifuged at 3000 rpm for 3 minutes on a 30-degree angle centrifuge. The obtained compound has a top layer of oil, a middle layer of fat (with the stromal vascular fraction (SVF) within at its lower portion), and an aqueous inferior layer. The top layer of oil is discarded while the plug still is on the syringe. The plug is then removed and the aqueous layer drains out per gravity. The remaining compound is sequentially injected into “insulin” syringes without the plunger, which is then replaced ( Fig. 1 ).
Using a 16-gauge needle, a perforation is made at an acute angle in healthy skin in the periphery of the wound or the scar. A 1.8-mm outside diameter (1.2-mm internal diameter) 70-mm long cannula already connected to the 1-mL syringe is inserted through the needle puncture hole and (forcefully) driven immediately under the wound bed or the scar. Fat is then deposited in a retrograde manner, in several “passes” until the entire area is injected (via as many puncture sites as needed around the periphery of the scar or wound). On average, 1.6 to 2.0 mL is injected per each 10 cm 2 area and it is necessary to make 25 to 30 passes to inject 1 mL. In chronic wounds, the induration, “healed” area in the periphery of the remaining wound, is also injected ( Figs. 2 and 3 , Videos 1–3 ).
Occasionally, when there are fracture lines of bone loss “voids” or exposed bone, fat is injected through the wound ( Fig. 4 A). Also, in wounds where the entire thickness of the skin or more tissue has been lost, fat is also deposited in a zigzag manner over the entire surface of the wound, also using the same cannula as for the injection (see Fig. 4 B).
There are patients with lesions that have been partially or poorly treated, sometimes who did not even have appropriate debridement of their original (or consequential) wound. In these cases, we perform one or more debridements, complementing them, if necessary, immediately before fat injection. In cases of open fractures, regardless of the presence or absence of internal or external hardware, we proceed routinely with fat injection and deposition in all areas of the wound with injection around and under, and deposition in all loss of substance voids, including bone spaces (please see [CR] ).
Potential complications and their management
Infection
Although infection is a common complication in burn and other trauma wounds, we have experienced no complications related to infection, even with injections through burn and other wounds and with fat deposited over the wound. We recommend, however, in wounds that are heavily contaminated, a debridement 2 days before the fat injection procedure.
Fat Grafting Technique or Procedure
Complications in fat grafting may be related to the procedure or technique themselves, mostly because of physical trauma to underlying structures by the cannula or other injection device. We favor the use of blunt cannulas with distal side openings, connected to a small-volume (1 mL) syringe, and that fat be injected in a retrograde manner, in multiple passes, depositing multiple, evenly distributed, streaks of fat with less than 2-mm diameter. When injecting under thick scar tissue, it may be safer to previously pass the cannula under the scar in several directions, “opening” the way for faster movements while injecting fat. This may be particularly useful when treating areas on the neck and face, where noble structures can be easily injured or perforated.
Although fat injection could be considered a minimally invasive procedure, fat obtention by liposuction is considered an invasive procedure and has to be performed with extreme caution and technical rigor, if such complications as asymmetry and trauma to fascia, to muscle, or even to viscera are to be avoided.
Because fat acquisition from very small patients is still infrequent, we recommend extreme care in harvesting it, while endeavoring to be symmetric and to obtain deeper fat (under Scarpa fascia) to avoid the occurrence of future superficial irregularities. Also, using slightly higher negative pressure (20-mL syringe) and multi (micro) perforated cannulas ensures faster and more precise fat harvesting. Assurance of long-term follow-up visits must be provided as the small patient grows.
Subdermal or Deep Vessel Injury
In the rare case that a subdermal or deeper vessel may be injured, local pressure and abortion of the injection on that site should be the immediate action. Ensuing ecchymosis disappears with time and the patient must be reassured about the evolution of this most unusual complication.
Edema
In scar cases, postoperative edema is a frequent event in the immediate days after the procedure and the patient must be warned about it.
Venous Ulcers
In patients with venous ulcer, postural drainage is fundamental for the success of treatment and one should inform the patient that the improvement of the wound does not substitute postural measures ( Fig. 5 ). In diabetic arterial disease, adequate footwear and proper foot care is a must for progressive weight bearing after healing without recurrence ( Fig. 6 ).
