Background Autogenous fat grafting (AFG) is an established technique used as an adjunct to breast augmentation (BA) to redesign breast shape. Surgeons often use experience and intuition to estimate AFG volume, which can result in incorrect assessment of donor areas and unnecessary fat removal. Objectives This aim of this study was to develop a method based on a mathematical formula, which utilizes implant volume and projection to predict AFG volume. Methods Thirty patients (60 breasts) underwent primary hybrid BA. A software package (SketchUp) was used to simulate 3-dimensional AFG and implant volumes, which in turn were used to develop an equation for estimating AFG volume according to 3 different implant projections. The results for each group were compared, via Pearson’s correlation coefficient, with the results of the clinical series. Results All patients received Motiva Ergonomix SmoothSilk/SilkSurface implants, ranging in volume from 175 to 355 cc (mean, 265 cc), as well as an average AFG volume of 79.2 cc/breast (range, 50-110 cc). Twenty-nine patients (96.6%) were either very satisfied or satisfied during a mean follow-up of 18 months (range, 6-28 months). A high correlation was observed between the AFG performed in the cohort and predictions obtained from the formula (r = 0.938, P < 0.001). Conclusions The AFG volume in hybrid BA procedures can be estimated utilizing measurements based on implant volume/projection. This low-cost method can be applied to guide surgical decision-making in patients who are candidates for BA. Level of Evidence: 4

Background: Autologous fat grafting is a procedure indicated for breast augmentation to improve coverage of silicone implants and redesign breast shape. Different techniques are based on parameters that have not been systematically standardized. The authors present a method using breast zone standardization based on breast anatomy to achieve an anatomical composite breast. Methods: The authors performed this zone standardization in 76 breasts (38 patients) undergoing primary/secondary augmentation. The area between the implant and the clavicle and parasternal area was marked to receive fat grafting and divided into three zones. A mathematical formula [volume of autologous fat graft = (π × r2 × p)/4.8] was used to estimate the fat graft volume according to implant volume in the respective zones. Results: Implant volumes ranged from 205 to 375 cc (mean, 265 cc), and patients received an average fat graft volume of 105.3 cc per breast (range, 36 to 135 cc); the average fat volume in zones I/II and III was 78.28 cc (range, 0 to 100 cc) and 27.03 cc (range, 15 to 60 cc), respectively. Three minor complications were observed (5.2 percent) during a mean follow-up of 12.8 months. A high correlation was observed between the fat grafting performed in the cohort and predictions obtained from the formula (p < 0.001). Conclusions: Recognizing risky cleavage breast zones between the implant pocket and the upper and medial quadrants remains essential to attain satisfactory outcomes. Although experience and proper judgment are still important in the fat grafting technique, the data presented here offer plastic surgeons an additional standardized framework to help deliver predictable hybrid breast augmentation.  CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.