Influence of Age, Sex, and Body Mass Index on the Thickness of the Gluteal Subcutaneous Fat: Implications for Safe Buttock Augmentation Procedures

Background: The deep intramuscular approach during buttock augmentation with fat grafting has been associated with a significantly increased risk for pulmonary fat embolism. This study was designed to provide guidance for injection into the subcutaneous fat. Methods: The authors investigated 150 Caucasian individuals with an equal distribution of men and women (n = 75 each) and a balanced distribution of age (n = 30 per decade: 20 to 29, 30 to 39, 40 to 49, 50 to 59, and 60 to 69 years) and body mass index (n = 50 per group: = 24.9 kg/m(2), between 25.0 and 29.9kg/m(2), and = 30 kg/m(2)). Ultrasound-based measurements were conducted of the thickness of the total, superficial, and deep gluteal fatty layers. Results: An increase in body mass index of 1.0 kg/m(2) corresponded to an increase of 3 mm of the total gluteal subcutaneous fat of men and a 4-mm increase of the total gluteal subcutaneous fat in women. With increasing age, the thickness of the deep fatty layer increased, whereas with increasing body mass index the thickness of the superficial layer primarily increased. Formulas were generated to estimate the total thickness of the gluteal subcutaneous fatty layer for men [total thickness (in millimeters) = -33.56 + (age x 0.078) + (body mass index x 3.042)] and women [total thickness (in millimeters) = -56.997 + (age x 0.1) + (body mass index x 3.86)]. Conclusions: Knowing the total thickness of the gluteal subcutaneous fat (i.e., the safe space) allows surgeons to estimate their operating range for cannula motion even if no ultrasound machine is available during buttock augmentation with fat grafting. This can increase safety, potentially reducing the number of adverse events.