Predicting Lower Pole Deformation in Breast Augmentation: A Biomechanical Analysis of Implant-to-Breast Matching Ratios.

[BACKGROUND] Predicting postsurgical morphometric changes in breast augmentation remains challenging. A key alteration is the increase in nipple-to-inframammary crease (N-IMC) distance, which affects aesthetics. This study quantifies N-IMC changes after subfascial breast augmentation and develops a predictive model incorporating anatomical and implant-related factors.

[METHODS] A retrospective analysis of 408 patients undergoing subfascial breast augmentation was conducted. Preoperative and postoperative morphometric measurements, including N-IMC distance, suprasternal notch-to-nipple distance, and breast width, were analyzed. Additional parameters, such as lateral sternal margin thickness and implant size, were assessed using multiple linear regression and stepwise selection. Two implant-to-breast matching ratios were introduced: the implant projection-to-breast width (R ib ratio) and the implant width-to-available breast width ratio.

[RESULTS] N-IMC distance increased by 52.98% on average, with variability influenced by patient anatomy suprasternal notch-to-nipple distance change ( P = 0.0019), and implant width-to-available breast width ratio ( P = 0.0482) were significant predictors. The R ib ratio had the highest predictive capacity, explaining 67.85% of lower pole deformation variability.

[CONCLUSIONS] Implant selection and breast tissue characteristics significantly impact postsurgical morphometry. The R ib ratio offers a standardized metric for implant selection, enhancing preoperative planning and aesthetic outcomes. Its adoption in clinical practice is recommended to improve surgical consistency.