The FALD-V: A predictive formula for preoperative volume assessment of adipose tissue transplantation in FALD flap

Background: The fat-augmented latissimus dorsi (FALD) flap is an evolution of the traditional latissimus dorsi (LD) flap, which allows to obtain a total autologous breast reconstruction (BR) avoiding the use of breast implants. The aim of this study was to develop a predictive preoperative formula in order to estimate and optimize the amount of fat to be transferred during FALD flap BR, using only anthropometric measurements. Methods: We conducted a prospective clinical study between September 2020 and April 2023. All patients underwent back pre-operative ultrasound scan to assess the subcutaneous skin paddle thickness (SPT) and a regression analysis was performed to evaluate which anthropometric variable had a better correlation with this thickness. Results: Data from 66 FALD flaps were collected. The mean SPT was 11.95 mm (SD 4.56). A significant correlation between SPT and body mass index (BMI) was found (r = 0.640, p < 0.0001). Using the fat-to-capacity ratio (113%), the following formula (the FALD-V) was developed to predict the needed fat transfer into FALD flap: [-509 + 12.32 × BMI + 11.71 × skin paddle width + 17.43 × skin paddle height] × 1.13. The considered variables (BMI, skin paddle width and skin paddle height) were statistically significant (p < 0.001, p = 0.0483, p = 0.0154, respectively). The cross-validation confirmed the accuracy of the formula (r = 0.810). Conclusion: The FALD-V can be used as an innovative complimentary device in the planning of FALD flap one-stage total autologous BR. To enhance its application, a 3.0 WebApp at www.braflap.com (and www.breast-v.com) is available free of charge for both iOS and Android devices. Level of evidence: II.