Fat Transfer

Fat transfer — also called lipofilling, autologous fat grafting, or lipofilling transplantation — is a plastic surgery technique in which adipose tissue is harvested from one area of the body (typically the abdomen, flanks, thighs, or hips), purified, and re-injected as a soft-tissue filler into another region that needs volume restoration or augmentation. Because the graft comes from the patient’s own body, it is biocompatible and carries no risk of allergic rejection, unlike synthetic fillers or implants.

The core principle is that a portion of the transferred fat establishes a new blood supply (neovascularization) at the recipient site and survives long-term as living tissue. The remaining fat is absorbed by the body during the first 3-6 months. Published meta-analyses report long-term fat survival in the range of approximately 40-80% depending on anatomical region, harvesting method, processing technique, and injection protocol (Gir et al., Plastic and Reconstructive Surgery, 2012; Strong et al., PRS Global Open, 2015). Because of partial resorption, touch-up sessions are sometimes planned.

Fat grafting has become one of the most widely performed procedures in plastic surgery, endorsed by the American Society of Plastic Surgeons (ASPS) and the International Society of Aesthetic Plastic Surgery (ISAPS) for a range of reconstructive and aesthetic indications. It can be used on its own or combined with liposuction body contouring, breast reconstruction, or facial rejuvenation procedures.

Fat transfer may be considered when a patient presents with, or seeks correction of, one or more of the following:

• Age-related facial volume loss (sunken cheeks, temporal hollowing, tear-trough depressions, thin lips, marionette lines)
• Loss of breast volume after pregnancy, weight loss, or aging; mild breast asymmetry; desire for modest augmentation without implants
• Post-lumpectomy or post-mastectomy defects requiring volume and contour correction (as part of a reconstructive plan)
• Flat, deflated, or asymmetric gluteal contour where the patient wishes a fuller, more projected buttock shape (BBL candidates)
• Depressed or adherent scars (post-traumatic, post-surgical, post-acne) where subcutaneous fill improves contour and scar quality
• Volume loss in the dorsum of the hand exposing tendons and veins (hand rejuvenation)
• Contour irregularities following prior liposuction or injury
• Congenital or acquired asymmetries where structural correction is not required

A surgical consultation assesses donor-site fat availability, recipient-site tissue quality, skin elasticity, BMI stability, and general health. Patients with very low body fat, unstable weight, active smoking, uncontrolled diabetes, or bleeding disorders may not be suitable candidates or may require preoperative optimization.

Fat transfer is performed in three sequential stages — harvest, processing, and re-injection — during the same operative session.

1. Harvest. The donor area (abdomen, flanks, inner or outer thighs, hips, or back) is infiltrated with a tumescent solution containing diluted local anesthetic and adrenaline to minimize bleeding. Fat is then aspirated using low-pressure liposuction through small cannulas (typically 2-4 mm in diameter). Low-negative-pressure technique and small-bore cannulas are preferred because excessive suction pressure damages adipocytes and reduces graft survival (Coleman technique and subsequent refinements).

2. Processing. The harvested lipoaspirate contains fat, blood, oil, and tumescent fluid. Before re-injection, it is purified using one or a combination of:

• Decantation (gravity separation)
• Centrifugation (commonly at approximately 1,200 g / 3 minutes, per the Coleman protocol)
• Washing/filtration systems that rinse the fat with saline and remove debris

3. Re-injection. The purified fat is transferred into small-gauge blunt-tip cannulas (typically 1-2 mm) and injected as micro-parcels along multiple tunnels and tissue planes. The “small aliquot, multi-pass” principle maximizes contact between grafted fat and surrounding vascularized tissue, improving survival. Typical volumes range from approximately 5-15 mL per side for facial fat grafting, 150-400 mL per breast, and 300-800+ mL per buttock in BBL cases.

Anesthesia depends on the extent of the procedure. Small-volume facial or hand grafting can be performed under local anesthesia with sedation; breast lipofilling, BBL, and combined liposuction-plus-transfer cases are typically performed under general or regional anesthesia. Operative time ranges from approximately 1 hour for an isolated facial procedure to 3-4 hours for a large combined liposuction-plus-BBL case. Most cases are same-day discharge or a single overnight stay.

Recovery has two parallel components: the donor (liposuction) site and the recipient (grafted) site. Bruising and swelling are expected at both, peaking within the first 3-5 days and settling substantially over 2-4 weeks. The final graft volume is typically assessed at 3-6 months, once resorption has stabilized.

• Compression garment: worn over the donor area for approximately 4-6 weeks to reduce swelling and support skin retraction
• No pressure on grafted areas: grafted fat needs an undisturbed recipient bed to establish a blood supply; direct pressure, massage, or heat can compromise survival
• For BBL specifically: patients are asked to avoid sitting directly on the buttocks for approximately 2-3 weeks (or to use a “BBL pillow” that offloads weight to the posterior thighs); sleeping on the stomach or side is recommended
• For facial grafting: sleep with the head elevated for the first week; avoid pressure from masks, tight hats, or side-sleeping on the grafted cheek
• Return to work: approximately 5-10 days for facial or hand grafting, 10-14 days for breast lipofilling, and 2-3 weeks for BBL, depending on the physical demands of the job
• Return to exercise: light walking from day 1-2; cardio at approximately 3-4 weeks; full strength training and contact sports at approximately 6 weeks
• Weight stability: maintaining a stable weight for at least 6 months protects the grafted volume, since surviving fat cells behave like native fat and respond to weight gain or loss

Smoking cessation for at least 4 weeks before and after surgery is strongly recommended, as nicotine impairs microcirculation and reduces graft survival. Post-operative follow-up visits typically occur at 1 week, 1 month, 3 months, and 6 months.

Fat grafting is generally considered a safe procedure in appropriately selected patients, but — like all surgery — it carries risks. Rates below are reported in peer-reviewed literature and society guidance; individual risk depends on anatomy, volume grafted, and surgical protocol.

Common, generally self-limiting:

• Bruising, swelling, and temporary numbness at donor and recipient sites (expected in nearly all cases)
• Partial resorption of grafted fat: long-term fat survival is approximately 40-80% depending on region and technique (Gir et al., 2012; Strong et al., 2015). Touch-up sessions may be planned
• Donor-site contour irregularity if liposuction is uneven

Less common:

• Fat necrosis (localized firm nodules where grafted fat did not survive): reported in approximately 3-10% of breast and BBL cases in meta-analyses
• Oil cysts (liquefied fat forming a small cyst; usually resolves or is aspirated): approximately 2-15% in breast lipofilling series
• Calcifications in breast lipofilling — typically benign “eggshell” or ring-type on mammography, but requiring experienced radiological interpretation to distinguish from malignancy-related microcalcifications (ASPS Fat Graft Task Force, 2009 and subsequent statements)
• Infection, seroma, or hematoma at donor or recipient site (<1-3%)
• Asymmetry or under-correction requiring revision
• Venous thromboembolism (DVT / pulmonary embolism): low but non-zero, particularly in longer combined cases

BBL-specific: fat embolism. Gluteal fat grafting has historically carried the highest mortality of any cosmetic procedure when fat is injected deep to, or into, the gluteal muscle, because fat can enter the gluteal veins and travel to the lungs and heart (macroscopic fat embolism). A 2017 international survey by the ASPS/ASERF Gluteal Fat Grafting Task Force reported a mortality rate of approximately 1 in 3,000 BBL procedures in that historical cohort, the highest of any aesthetic operation (Mofid et al., Aesthetic Surgery Journal, 2017).

In response, the Multi-Society Gluteal Fat Grafting Task Force (ASPS, ASERF, ASAPS, ISAPS, IFATS) issued formal safety advisories in 2018 and updated statements thereafter. The core protocol:

• Inject fat strictly into the subcutaneous plane — never into or beneath the gluteal muscle
• Hold the cannula parallel to the skin and maintain a consistent superficial angle
• Use larger-bore (e.g., ≥4 mm), rigid cannulas to reduce deep migration
• Consider real-time intraoperative ultrasound guidance to confirm subcutaneous injection plane
• Avoid aggressive multi-directional deep passes

Follow-up studies after the 2018 advisory and subsequent ultrasound-guided protocols have reported a significant reduction in BBL fat-embolism mortality in compliant practices (e.g., Cansancao et al., PRS Global Open, 2019; Del Vecchio et al., Aesthetic Surgery Journal, 2020). Confirming that the surgeon follows the current Task Force subcutaneous-only protocol — and operates in an accredited facility — is therefore central to BBL safety.

Patients should discuss their personal risk profile, comorbidities, medication list (especially anticoagulants), and smoking status with the surgical team during the preoperative consultation.