The Role of Density in Achieving Volume and Weight Symmetry in Breast Reconstruction.

Background:  Knowledge of tissue and implant density is crucial in obtaining both volume and weight symmetry in unilateral breast reconstruction. Therefore, the aim of this study was to determine and compare the density of abdominal and breast tissue specimens as well as of 5th generation breast implants.

Methods:  Thirty-one breast tissue and 30 abdominal tissue specimens from 61 patients undergoing either mammaplasty or abdominoplasty as well as five different 5th generation breast implants were examined. Density (g/mL) was calculated by applying the water displacement method.

Results:  The mean specimen density was 0.94 ± 0.02 g/mL for breast tissue and 0.94 ± 0.02 g/mL for abdominal tissue, showing no significant difference ( = 0.230). Breast tissue density significantly ( = 0.04) decreased with age, while abdominal tissue did not. A regression equation to calculate the density of breast tissue corrected for age (breast density [g/mL] = 0.975-0.0007 * age) is provided. Breast tissue density was not related to body mass index, past pregnancy, or a history of breastfeeding. The breast implants had a density ranging from 0.76 to 1.03 g/mL which differed significantly from breast tissue density (-0.19 g/mL [-19.8%] to +0.09 g/mL [+9.58%]; ≤ 0.001).

Conclusion:  Our results support the suitability of abdominal-based perforator flaps in achieving both volume and weight symmetry in unilateral autologous breast reconstruction. Abdominal flap volume can be derived one-to-one from mastectomy weight. Further, given significant brand-dependent density differences, the potential to impose weight disbalances when performing unilateral implant-based reconstructions of large breasts should be considered.