Histological and Biomechanical Comparison of Different Dissection Planes in Brow Lift: An Experimental Rabbit Model and Its Clinical Implications.

BACKGROUND: Different dissection planes used in brow lift surgery-namely, subcutaneous, subgaleal, and subperiosteal-present distinct biomechanical and histological characteristics. This study aimed to compare these three dissection approaches in terms of tissue healing and mechanical resistance. METHODS: In this experimental model using New Zealand white rabbits, three groups of eight animals each underwent subcutaneous, subgaleal, or subperiosteal dissection. After a 12-week healing period, tissue samples were harvested for either histological or biomechanical analysis. Epidermal, dermal, superficial musculoaponeurotic system (SMAS), and periosteal thicknesses were quantitatively measured using ImageJ software. Biomechanical parameters assessed included maximum load, stiffness, and yield load. RESULTS: Histological evaluation revealed preserved tissue integrity in all groups, with no evidence of fibrosis or disrupted collagen organization. A statistically significant difference in the epidermis/dermis ratio was observed between the control group and both the subgaleal and subperiosteal groups (p < 0.05). In biomechanical testing, the subperiosteal group demonstrated significantly superior values for maximum load, stiffness, and yield load compared to the other groups (p < 0.05). CONCLUSION: These findings suggest that while the subperiosteal plane offers greater long-term mechanical stability, the subcutaneous approach may support a more physiological healing pattern. This is supported by its closer resemblance to the control group in epidermis-to-dermis ratios and the absence of fibrotic remodeling. The preservation of native tissue architecture in this group highlights its potential as a biologically favorable plane in selected patients. Dissection plane selection should be individualized based on the patient's specific tissue characteristics and surgical goals. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes review articles, book reviews, and manuscripts that concern basic science, animal studies, cadaver studies, and experimental studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .