Augmented Safety Profile of Ultrasound Guided Gluteal Fat Transfer: Largest Retrospective Study to Date with 1815 Patients

Goals/Purpose: Gluteal contouring and augmentation with autologous fat transfer, colloquially referred to as the "Brazilian butt lift", is among the fastest growing aesthetic surgical procedures in the United States over the past decade. However, this procedure can be associated with high mortality from fatal pulmonary fat embolism events and has received much attention in the media. Guidelines from the Aesthetic Surgery Education and Research Foundation Task Force on Gluteal Fat Grafting recommend against deep muscle layer injection. Traditionally the fat transfer is done blindly with proper location based solely on experience and feel. Ultrasound guidance allows the surgeon to be able to see the cannula in real time. Recently the Florida Department of Health instituted an emergency rule mandating all surgeons to use ultrasound imaging when performing this procedure. This has been supported by the ASPS and ASAPS. In our busy surgical practice, ultrasound guided gluteal fat transfer has been performed since 2019. The aim of the current study was to assess the safety and efficacy for gluteal fat grafting utilizing ultrasound (US) guided cannulation.

Methods/Technique: A retrospective chart review of all patients undergoing ultrasound guided gluteal fat grafting at our center was performed from 2019 to 2022. All cases were performed by board certified and board eligible plastic surgeons under general anesthesia in ASA class I or II patients. For the fat transfer, patients were in prone, flexed position and a portable ultrasound was used to assess the gluteal layers in real time. Fat was only transferred to the subcutaneous plane over the gluteal muscle. Patients underwent postoperative follow-up from a minimum of 3 months up to 2 years. Results were analyzed using standard statistical tests.

Results/Complications: There were 1,815 patients during the study period with a median age of 34 years old. Controlled medical comorbidities were present in 14% with the most frequent being hypothyroidism (0.7%), polycystic ovarian syndrome (0.7%), anxiety (0.6%), and asthma (0.6%). Postoperative complications occurred in 4% of the total cohort with the most common being seroma (1.2%), local skin ischemia (1.2%), and surgical site infection (0.8%; Table 1). There was 0% macroscopic fat emboli complications or mortalities. The use of ultrasound did not significantly increase surgical time.

Conclusion: These data suggest that direct visualization of anatomical plane injection using US guidance is associated with a low rate of complications. It allows for direct visualization of the cannula in real time to assure fat is placed in the safe subcutaneous plane thereby minimizing the risk of fat embolism. The ultrasound device is affordable and does not add significant additional time to the procedure. It is also an essential tool for training new surgeons on this procedure safely. US-guidance is an efficacious adjunct to gluteal fat grafting and associated with an improved safety profile that should be considered the standard of care for gluteal fat grafting.