The Impact of Preoperative Breast Volume on Development of Mastectomy Skin Flap Necrosis in Immediate Breast Reconstruction.

Background: Mastectomy skin flap necrosis (MSFN) can significantly impact outcome after immediate breast reconstruction. Several techniques exist to predict MSFN, but these may require additional testing and information, and they are often not available before surgery. We aim to identify whether breast volume, as calculated from preoperative mammography, can be used as a preoperative predictor of MSFN.

Methods: A retrospective chart review from 2010 to 2020 resulted in 378 patients who underwent immediate implant-based breast reconstruction. Complete imaging data were available for 278 patients and 441 reconstructed breasts. Demographic, perioperative, and outcomes data were collected. Measurements from preoperative diagnostic mammograms were used to calculate breast volume. Univariate and multivariate analyses were used to evaluate the association of variables available preoperatively, including breast volume from mammogram and MSFN. Secondary analyses were performed for need for reoperation and loss of reconstruction.

Results: On univariate analysis of MSFN development, demographic variables found to be significantly associated with MSFN included body mass index (P = 0.04), diabetes (P = 0.03), and breast volume calculated from routine mammography (P ≤ 0.0001). Average preoperative breast volume via mammography without and with MSFN was 970.6 mL (95% confidence interval [CI], 908.9-1032.3) and 1298.3 mL (95% CI, 1140.0-1456.5) (P < 0.0001), respectively. Statistically significant intraoperative variables for MSFN development included prolonged operative time (P = 0.005), greater initial tissue expander fill volumes (P ≤ 0.001), and prepectoral implant location (P = 0.02). Higher initial tissue expander fill volumes in implant-based reconstructions were associated with increased rates of MSFN, 264.1 mL (95% CI, 247.2-281.0) without MSFN and 349.9 mL (95% CI, 302.0-397.8) in the group with MSFN, respectively (P < 0.001). On multivariate analysis, preoperative imaging volume (P = 0.02) was found to be significant, whereas body mass index and diabetes lost significance (P = 0.40) in association with MSFN.

Conclusions: The results of this study establish an association between larger breast volume on preoperative imaging and development of MSFN. This may be useful as a tool for more appropriate patient selection and guidance in the setting of immediate breast reconstruction.