An Evaluation of Native Breast Dimension and Tissue Expander Inflation Rate on the Risk of Capsular Contracture Development in Postmastectomy Reconstruction.

INTRODUCTION: Capsular contracture is a common complication after 2-stage breast reconstruction. The relationships between native breast size, the rate of tissue expander expansion, and capsule formation have not been elucidated. This study aims to evaluate how these factors contribute to capsular contracture and establish cutoff values for increased risk. METHODS: A data set consisting of 229 patients who underwent 2-stage breast reconstruction between 2012 and 2021 was included in the study. The rate of expansion is estimated as the final expanded volume subtracted by the initial filling volume of the tissue expander over time elapsed. The native breast size was estimated using various preoperative breast measurements and the weight of mastectomy specimen (grams). Further stratified analysis evaluated patients separately based on postoperative radiation status. RESULTS: Greater nipple-inframammary fold distance and faster tissue expander enlargement rate conferred decreased odds of developing capsular contracture ( P < 0.05). On stratified analysis, faster tissue expansion rate was not significant in the nonradiated cohort but remained a significant negative predictor in the radiation group (odds ratio, 0.996; P < 0.05). Cut-point analysis showed an expansion rate of <240 mL/mo and a nipple-inframammary fold value of <10.5 cm as conferring a greater risk of capsular contracture. CONCLUSION: Smaller inframammary fold distance may be associated with a higher risk of capsular contracture. Slower expansion rates correlate with increased odds of contracture in patients undergoing adjuvant radiation. Breast geometry should be considered when risk stratifying various reconstruction approaches (implant vs autologous). In addition, longer delays between implant exchange and initial tissue expansion should be avoided if clinically feasible.