Structural Gender Dimorphism and the Biomechanics of the Gluteal Subcutaneous Tissue: Implications for the Pathophysiology of Cellulite

Background: This study was performed to investigate gender differences in gluteal subcutaneous architecture and biomechanics to better understand the pathophysiology underlying the mattress-like appearance of cellulite. Methods: Ten male and 10 female body donors [mean age, 76 +/- 16.47 years (range, 36 to 92 years); mean body mass index, 25.27 +/- 6.24 kg/m(2) (range, 16.69 to 40.76 kg/m(2))] were used to generate full-thickness longitudinal and transverse gluteal slices. In the superficial and deep fatty layers, fat lobule number, height, and width were investigated. The force needed to cause septal breakage between the dermis and superficial fascia was measured using biomechanical testing. Results: Increased age was significantly related to decreased dermal thickness, independent of sex (OR, 0.997, 95 percent CI, 0.996 to 0.998; p < 0.0001). The mean number of subdermal fat lobules was significantly higher in male body donors (10.05 +/- 2.3) than in female body donors (7.51 +/- 2.7; p = 0.003), indicating more septal connections between the superficial fascia and dermis in men. Female sex and increased body mass index were associated with increased height of superficial fat lobules. The force needed to cause septal breakage in male body donors (38.46 +/- 26.3 N) was significantly greater than in female body donors (23.26 +/- 10.2 N; p = 0.021). Conclusions: The interplay of dermal support, septal morphology, and underlying fat architecture contributes to the biomechanical properties of the subdermal junction. This is influenced by sex, age, and body mass index. Cellulite can be understood as an imbalance between containment and extrusion forces at the subdermal junction; aged women with high body mass index have the greatest risk of developing (or worsening of) cellulite.