Volume changes in the reconstructed breast over two years after free abdominal tissue transfer: Comparison of unipedicled versus bipedicled flaps

Background: Volume changes in reconstructed flaps, particularly regarding symmetry, are an important consideration to improve long-term esthetic results in patients who undergo breast reconstruction. Asian patients with thin abdominal tissues tend to require bipedicled flaps, which provide a greater volume of abdominal tissue. We investigated volume changes in free abdominal flaps and the factors that may affect flap volume, particularly the number of pedicles. Methods: The study included all consecutive patients who underwent immediate unilateral breast reconstruction using free abdominal flaps between January 2016 and December 2018. The initial flap volume was calculated intraoperatively, and the postoperative flap volume was calculated using computed tomography or magnetic resonance imaging based on the Cavalieri principle. Results: The study included 131 of 249 patients. Compared with the initial inset volume, the mean flap volumes at 1 and 2 years postoperatively decreased to 80.11% and 73.80%, respectively. The multivariable analysis of factors that affect flap volume showed a significant association with the flap inset ratio, radiation (P = .019,.040, respectively). Stratification based on the number of pedicles showed that the flap inset ratio was significantly negatively correlated with the postoperative flap volume change in unipedicled (P < .05) but not in bipedicled flaps. Conclusions: The flap volume decreased over time, and its change had a negative correlation with the flap inset ratio in the unipedicled group. Therefore, prediction of postoperative volume changes in various clinical situations is important before breast reconstruction.