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

OBJECTIVE: 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 the injection into the subcutaneous fat i.e. the area between the muscle and the skin; the so-called "safe space".

MATERIAL AND METHODS: A total of 150 Caucasian individuals were investigated with an equal distribution of males and females (each n=75) and a balanced distribution of age (n=30 per decade: 20-29, 30-39, 40-49, 50-59 and 60-69 years) and body mass index (BMI) (n=50 per group: BMI≤24.9kg/m, BMI between 25.0 and 29.9kg/m BMI≥30kg/m. Ultrasound-based measurements were conducted of the thickness of the total, superficial and deep gluteal fatty layers.

RESULTS: An increase in 1.0 BMI value corresponded to an increase of 3mm of the total gluteal subcutaneous fat of males and a 4mm increase of the total gluteal subcutaneous fat in females. With increasing age, the thickness of the deep fatty layer increased while with increasing BMI the thickness of the superficial layer primarily increased. A formula was generated to estimate the total thickness of the gluteal subcutaneous fatty layer: Males: Total thickness (mm)=-33.56+(agex0.078)+(BMIx3.042); Females: Total thickness (mm)=-56.997+(agex0.1)+(BMIx3.86).

CONCLUSION: 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.