Rectus Abdominis Fat Grafting: Outcomes and Safety.

Abdominal fat grafting is a surgical technique designed to increase the volume of the rectus abdominis muscles. This procedure involves harvesting adipose tissue with a cannula from donor areas such as the abdomen, inner thighs, or arms. 1 , 2 The harvested fat is processed to eliminate impurities such as blood, oil, and cellular debris, typically through centrifugation, filtration, or sedimentation 3 , 4 ; the purified fat is then reinjected into the abdominal wall to enhance the volume and contour of the rectus abdominis muscles, yielding favorable and long-lasting aesthetic results. 4 , 5 The history of fat grafting dates to the late 19th century. In 1889, Van der Meulen performed the first documented attempt at autologous fat transfer to repair a diaphragmatic hernia. 6 During the early 20th century, fat grafting gained popularity across various medical specialties. By 1911, Brunning had introduced the use of syringes for fat injection, although fat resorption remained a major challenge. 7 Subsequent innovations related to liposuction significantly enhanced the reliability of fat grafting procedures. In 1975, Arpad and Giorgio Fischer developed modern liposuction, enabling safer fat harvesting. 8 Illouz further refined the technique in 1977 by introducing blunt cannulas and a suction-assisted method (the wet technique), which improved the safety and efficacy of fat extraction. 9 In 1988, Toledo optimized the process using syringes for aspiration, allowing greater precision and minimizing tissue trauma. 10 The most transformative advancement came in 1986 with Coleman’s technique, which revolutionized fat grafting by emphasizing atraumatic harvesting, careful refinement, and precise reinjection. This marked a turning point, establishing fat grafting as a dependable method for both reconstructive and aesthetic purposes, with significantly improved patient outcomes. 11 , 12 Today, fat grafting continues to be widely performed and highly effective due to these foundational advancements. Techniques have evolved to include direct visualization during lipoabdominoplasty procedures 13 as well as ultrasound-guided approaches using multiple ports 14 or a unique port with a long cannula. 15 Although complications related to rectus abdominis fat grafting have been extensively reported in the literature, precise incidence rates remain undefined. The most common adverse events include fat necrosis, surgical-site infection, and aesthetic irregularities. 16 , 17 The aim of this article was to present our clinical experience with rectus abdominis fat grafting and to report a low complication rate using our standardized technique.

For a detailed demonstration of the procedure, see Videos 1 and 2 for fat grafting after liposuction and Videos 3 and 4 for fat grafting after abdominoplasty. ( See Videos 1 and 2 [online] , which show fat grafting after liposuction.) ( See Videos 3 and 4 [online] , which show fat grafting after abdominoplasty.) Video 1. Fat grafting after liposuction, part 1. GOX.0000000000007546video1.mp4 Kaltura Video 2. Fat grafting after liposuction, part 2. GOX.0000000000007546video2.mp4 Kaltura Video 3. Fat grafting after abdominoplasty, part 1. GOX.0000000000007546video3.mp4 Kaltura Video 4. Fat grafting after abdominoplasty, part 2. GOX.0000000000007546video4.mp4 Kaltura The patient, in a supine position, is infiltrated with a total of 2 L of tumescent solution using a 3-mm cannula and infiltration system in the abdomen and inner thighs (wet technique). The tumescent solution consists of 1 L of 0.09% saline with 1 ampoule of epinephrine (1 mg/mL). Ports are created for liposuction and subsequent rectus abdominis fat grafting: Two 5-mm incisions at the pubic level. One 5-mm incision in each inframammary fold. One 5-mm incision at the umbilical level. Liposuction is performed as follows. An ultrasound-assisted liposuction system is used at 70% power for 10 minutes in the subcutaneous tissue to emulsify fat. Fat is aspirated using a power-assisted liposuction device with 4–5 mm flared Mercedes cannulas. The extracted fat is decanted into a canister and washed with 1 L of 0.09% saline solution. To prevent clogging of the infiltration cannula, the fat is passed through a 3-way stopcock before use (Fig. 1 ). Preparation of the adipose tissue. A, Harvested adipose tissue before processing. Macroscopic view of the lipoaspirate collected using the power-assisted liposuction system. The separation of the oil, aqueous layer, and intact adipocytes is visible before decantation and washing. B, Processed fat after decantation and filtration. Standardized volumes of purified adipose tissue are prepared in 60-mL syringes, showing a homogeneous graft ready for injection through a stopcock system to prevent clogging of the infiltration cannula. Ultrasound guidance is mandatory for this procedure, as described by Viaro et al. 12 A linear transducer and a 3.5-mm sharp-tipped Luer-lock cannula with a single posterior opening (15.8 cm in length) are used for precise and safe intramuscular fat delivery. Portal used: umbilical. Under ultrasound guidance, the cannula tip and fascia perforation are confirmed at the level of the second metamere. Once the cannula is advanced into the superficial intramuscular plane, it is directed cranially to reach the superior metamere. A retrograde injection of 10 mL in women and 15 mL in men is performed in the superior metamere using a fan-like pattern (2–3 passes). In the second metamere, an additional 20 mL in women and 25 mL in men is injected using the same technique. The cannula tip and fascia perforation are again confirmed at the level of the third metamere under ultrasound, where another retrograde fan-like injection of 20 mL in women and 25 mL in men is performed. Digital pressure is applied along the suprapubic portion of the rectus abdominis to ensure homogeneous graft distribution. The procedure is performed bilaterally (Figs. 2 A–C). Ultrasound-guided intramuscular fat injection. A, Ultrasound image showing the rectus abdominis muscle architecture before fat injection. Longitudinal sonographic view demonstrating the hypoechoic rectus abdominis muscle between the anterior and posterior fascia layers. B, Ultrasound-guided identification of the cannula tip within the rectus abdominis muscle. The echogenic cannula is visualized penetrating the anterior fascia and positioned correctly within the muscle belly before fat graft injection, ensuring intramuscular delivery and avoiding vascular structures. C, Postinjection ultrasound verification of fat distribution in the rectus muscle. The image shows well-dispersed echogenic areas in the targeted muscle zone with no signs of extrusion, supporting proper intramuscular deposition. Portal used: right and left pubis. With ultrasound guidance, the cannula is advanced into the intramuscular plane of the rectus abdominis to target the infraumbilical region. A retrograde fan-like injection of 30 mL in women and 40 mL in men is administered along the upper two-thirds of the infraumbilical rectus abdominis. Digital pressure is applied to ensure uniform distribution. The procedure is performed bilaterally. Portal used: right and left pubis. Under ultrasound guidance, the cannula is introduced into the superficial intramuscular plane of the middle oblique muscle. A retrograde fan-like injection of 30 mL is performed bilaterally. In male patients, an additional 20 mL is injected into the external oblique muscle using the same fan-shaped pattern. Digital pressure is applied over the oblique muscle region to homogenize the graft distribution. Muscle augmentation is performed under direct vision following flap elevation through a supraumbilical incision, as described by Danilla. 11 A narrow subcutaneous tunnel is dissected, with lateral dissection limited to the medial edge of the rectus abdominis at the supraumbilical level. Fat grafting is conducted before rectus muscle plication and diastasis repair. The same ultrasound-compatible cannula is used bilaterally for injections in the second and third metameres, as well as the caudal segment of the rectus abdominis. Under direct visualization, the cannula is advanced through the fascia and into the rectus muscle up to the superior metamere (Fig. 3 ). Direct visualization of intramuscular fat grafting during abdominoplasty. Dissection exposes the rectus abdominis muscle with a visible cannula track. Fat is injected under direct vision in the intramuscular plane before plication and closure. A retrograde fan-like injection (2–3 passes) is performed across all 3 supraumbilical metameres (50 mL in women, 65 mL in men). Bilateral fascia perforation and intramuscular grafting are also completed in the upper two-thirds of the infraumbilical segment (30 mL in women, 40 mL in men). Incisions are left open to allow passive drainage in the event of fat necrosis. Final ultrasound verification is performed to assess graft distribution and confirm the absence of extrusion during muscle contraction.

Patients provided written consent for the use of their images.

This article aimed to present our clinical experience with rectus abdominis fat grafting. Through this study, we were able to report the incidence of postoperative complications and describe the key surgical and demographic characteristics associated with the procedure. The median patient age was 37.2 years, and most patients were women, which aligns with demographic data reported in previous literature, where most patients fall between 35 and 50 years of age. 18 On average, 115 mL of fat was injected into the abdominal wall, with a distribution of 15 mL in the first metamere, 20 mL in the second metamere, 20 mL in the third metamere, 30 mL in the fourth metamere, and 30 mL into the oblique muscles. This volume is consistent with the amounts described by Danilla et al 13 in the rectus abdominis fat transfer study; notably, the use of small, anatomically targeted fat volumes is associated with favorable aesthetic outcomes and reduced rates of fat reabsorption. Furthermore, limiting the injected volume per area may also reduce the risk of fat necrosis due to better perfusion and integration of the graft. 13 The overall complication rate for all procedures performed (liposuction, abdominoplasty, and fat grafting) was 9.89%, which is lower than the average rate reported for body contouring surgeries in the literature (11.17%). 19 Importantly, only 2 cases (1.09%) were directly attributable to rectus abdominis fat grafting: 1 surgical-site infection and 1 instance of fat necrosis. These findings are consistent with the most frequently reported complications associated with this procedure. 16 , 17 Fat necrosis remains the most common complication of rectus abdominis fat grafting. It is characterized by degeneration of adipose tissue, which can lead to the formation of palpable nodules, cysts, and calcifications, often resulting in pain and aesthetic deformity. The principal cause is inadequate vascular supply, leading to ischemia of the grafted fat. 16 , 20 To mitigate this risk, we routinely used ultrasound to identify perforating vessels in the rectus muscle before fat injection, particularly rectus abdominis perforators that may influence graft survival, and to avoid fat embolism by following principles adapted from gluteal fat grafting safety guidelines 21 (Fig. 5 ). Although fat is not injected directly into these vessels, targeting nearby well-perfused areas may enhance adipose integration, following the principle of “vascular zones of reliability” described in flap surgery 22 ; complementary studies are required to validate this point of view. Infection is the second most common complication and occurs when grafted fat becomes colonized by pathogenic microorganisms. Clinical manifestations include fever, localized erythema and tenderness, systemic symptoms, and—in severe cases—sepsis or death. Early diagnosis and prompt management are critical to ensure favorable outcomes. Initial treatment involves empirical antibiotic therapy; in more severe cases, imaging and culture-guided treatment may be required, along with surgical drainage if indicated. 23 – 25 For mild, localized infections, clindamycin is often used due to its efficacy against anaerobic and Gram-positive organisms. 26 In more severe infections, gentamicin—a broad-spectrum aminoglycoside—may be used, though renal and auditory function must be closely monitored due to its potential toxicity. Alternative broad-spectrum regimens include ampicillin/sulbactam or fluoroquinolones such as moxifloxacin and ciprofloxacin, which are useful for patients with beta-lactam allergies. 27 , 28 In cases involving methicillin-resistant Staphylococcus aureus or severe soft tissue infections, linezolid is recommended due to its proven efficacy. 27 In our study, only 1 patient developed fat necrosis, presenting on postoperative day 12 with localized induration and mild tenderness in the infraumbilical region; ultrasound confirmed a small hypoechoic area without abscess formation. Management included conservative treatment with oral clindamycin for 7 days and gentle massage; no surgical drainage or debridement was required. At 6-month follow-up, the patient showed complete resolution of symptoms, and the resulting aesthetic outcome was deemed acceptable, with only mild asymmetry that did not necessitate revision. In our series, 1 patient developed a postoperative pulmonary thromboembolism. The diagnosis was confirmed through a stepwise evaluation: the patient first presented with unilateral calf pain and swelling, and Doppler ultrasound demonstrated a deep vein thrombosis. Shortly thereafter, the patient developed dyspnea and chest discomfort, and computed tomography pulmonary angiography revealed a segmental pulmonary embolism. Laboratory testing supported the diagnosis with elevated D-dimer levels, and imaging excluded fat attenuation within the pulmonary parenchyma. Importantly, the patient exhibited rapid clinical improvement following anticoagulation therapy—an evolution consistent with thromboembolic disease but not with fat embolism syndrome, which typically presents with the triad of hypoxemia, neurological impairment, and petechiae and does not respond to anticoagulation. 27 , 28 Based on these findings, we classified this case as a classic thromboembolic event associated with postoperative venous stasis rather than as a fat grafting-related complication. Although we did not directly evaluate the relationship between BMI and rectus muscle size or donor fat volume, clinical observations suggest that patients with higher BMI generally offer a greater volume of harvestable fat. 29 However, our fat grafting protocol does not rely on the abundance of available fat but rather on standardized volumetric targets and anatomical safety considerations guided by ultrasound. Furthermore, the baseline thickness and size of the rectus abdominis muscles appear to be more strongly influenced by sex and muscle training than by BMI alone, as supported by prior literature. 30 , 31 We excluded active tobacco users from the study due to the well-documented negative effects of tobacco use on wound healing, vascularization, and fat graft survival; smoking induces peripheral vasoconstriction, impairs tissue oxygenation, and increases the risk of infection, necrosis, and thromboembolic events, 32 which could introduce bias into the present analysis. Although fat grafting can technically be performed in this population, these risks must be carefully considered, and the risk–benefit ratio should be thoroughly evaluated before offering the procedure. Future studies with imaging-based volumetric assessments could better elucidate the influence of BMI on graft volume selection and outcomes, as well as incorporate various strategies to enhance both patient safety and graft viability, including the potential use of hyperbaric oxygen therapy to reduce the incidence of postoperative complications and improve long-term fat graft survival. 33 , 34 However, it is important to acknowledge the limitations of this study. First, it is a study that demonstrates the experience of performing rectus abdominal fat grafting in aesthetic plastic surgery practice but does not make comparisons between groups to demonstrate the effectiveness of different techniques or the use of any technology. Second, as a retrospective study, it was not possible to delve into new variables of interest, such as the absence of objective volumetric measurements of fat retention over time. Although ultrasound was systematically used intraoperatively to guide fat delivery and verify fascial perforation, standardized follow-up imaging to quantify fat resorption or retention was not performed, nor were patient interviews conducted.

RAFG procedures, such as those described by Danilla and Viaro et al, 11 , 12 are safe and effective in patients with no history of active smoking for enhancing abdominal contour, particularly when performed under ultrasound guidance or direct visualization. The use of small-volume, anatomically distributed fat grafts guided by ultrasound seems to minimize complications while achieving long-lasting aesthetic outcomes and high patient satisfaction. Further prospective studies are warranted to objectively assess long-term fat retention using imaging modalities and to compare different grafting techniques and safety strategies.

The authors have no financial interest to declare in relation to the content of this article.

No pharmacological thromboprophylaxis was administered preoperatively. Intraoperatively, intermittent compression stockings were used. Postoperatively, patients used medium-compression stockings for 3 weeks and received Fraxiparine 0.3 mL subcutaneously once daily, starting 12 hours after surgery and continued for 10 days. To evaluate the success of the intervention, we looked for the complication incidence. Patient satisfaction was assessed by analyzing changes in BODY-Q abdomen scale scores preoperatively versus postoperatively after 6 months, providing a measure of satisfaction with the outcomes of the procedure. Informed consent (for the surgical procedure, use of images, and use of data for research) was obtained from each patient before surgery. Patients were free to refuse to participate in the study or to withdraw consent at any time. This research was done in accordance with the Declaration of Helsinki. Descriptive statistics were used to summarize patient information. Jamovi statistical software (The jamovi Project, Australia; version 2.5; retrieved from https://www.jamovi.org ) was used for both univariate and multivariate analyses. A total of 182 patients underwent rectus abdominis fat grafting using the described protocol. The mean patient age was 37.2 years, with an average weight of 69.6 kg, a mean height of 1.62 m, and a BMI of 26.4 kg/m 2 . The most frequent comorbidities were hypothyroidism (13 patients), arterial hypertension (4 patients), and rheumatoid arthritis (3 patients) (Table 1 ). Demographic Characteristics NA, not applicable. Regarding the surgical procedures, the mean total operative time was 366 minutes. When broken down by component, liposuction had a mean duration of 120 minutes (SD 24.3), abdominoplasty required an average of 185 minutes (SD 29.7), rectus abdominis fat grafting took approximately 31 minutes (SD 10.2), and other procedures (mammoplasty, buttocks augmentation, etc.) took an average of 65 minutes (SD 16.7). A total of 161 (88.4%) patients underwent abdominoplasty, whereas 21 (11.5%) underwent liposuction alone. All procedures were performed under general anesthesia using the wet technique. On average, 85 mL of fat was injected into the rectus abdominis muscle per patient, with a mean distribution of 15 mL in metamere 1, 20 mL in metamere 2, 20 mL in metameres 3, and 30 mL in metamere 4 (Table 2 , Fig. 4 A and 4 B, and Fig. 5 ). Surgical Procedure Data NA, not applicable. Preoperative and postoperative magnetic resonance images. A, Preoperative axial magnetic resonance imaging scan showing baseline rectus abdominis muscle thickness. B, Postoperative axial magnetic resonance imaging at 6 months showing increased muscle thickness. Ultrasound Doppler image showing a rectus abdominis perforating artery. The vessel is identified with a diameter of 1.28 mm—smaller than the grafting cannula—underscoring the importance of ultrasound guidance to avoid intravascular injection and minimize risk of fat embolism. Complications directly attributable to rectus abdominis fat grafting occurred in only 2 cases (1.09%), including 1 surgical-site infection and 1 case of fat necrosis. No instances of fat embolism were reported. Postoperative complications occurred in 18 (9.88%) patients, but 16 of these were related to other procedures performed during the same surgical session. These included surgical-site infections (4 patients), wound dehiscence (3 patients), seroma (2 patients), abdominal wall hematoma (2 patients), hypertrophic scarring (2 patients), abdominal wall abscess (1 patient), abdominal flap necrosis (1 patient), posttraumatic panniculitis (1 patient), and pulmonary thromboembolism (1 patient) (Table 3 ). Patient satisfaction was assessed using the BODY-Q abdomen scale. The mean satisfaction score improved from 12.5 (preoperative) to 26.2 (postoperative) on a 28-point scale, indicating a high degree of patient-perceived aesthetic improvement (for the aesthetic results, see Figs. 6 – 8 ). Surgical Complications Case 1: moderate definition with rectus abdominis fat grafting and liposuction. A, Preoperative frontal view of a 40-year-old woman. B, Twelve-month postoperative result showing improved abdominal contour and mild muscle definition after rectus abdominis fat grafting and liposculpture. No complications were reported. Case 2: High-definition abdominal contour following rectus abdominis fat grafting and mini lipoabdominoplasty. A, Preoperative frontal view of a 34-year-old woman. B, Twelve-month postoperative result demonstrating enhanced muscle definition, waistline narrowing, and sustained graft volume retention. Ultrasound and clinical evaluation confirmed long-term outcome stability. Case 3: rectus abdominis fat grafting in a male patient. A, Preoperative image of a 42-year-old man with abdominal volume excess and poor muscular definition. B, Twelve-month postoperative result following high-definition liposuction, abdominoplasty, and intramuscular rectus abdominis fat grafting, showing enhanced abdominal contour and improved muscular definition.