Tissue Expansion after Non-Skin-Sparing Mastectomy: A Comparative Study of Expansion Courses of Prepectoral and Subpectoral Tissue Expander Placement with Acellular Dermal Matrix

Although skin- or nipple-sparing mastectomy has been popular in the treatment of breast cancer, the radical excision of breast tissue is unavoidable in certain circumstances. However, the ability of an acellular dermal matrix (ADM) to expand remains questionable, and this situation may further hinder tissue expansion. From October 2017 to January 2020, patients who underwent immediate breast reconstruction with tissue expander placement using ADM whose initial fill volume was less than 50 mL were retrospectively reviewed. The primary outcomes were the number of visits and number of days required to complete the expansion, and the secondary outcomes were the amount of postoperative expansions, expander fill ratio and expander volume. Between the prepectoral group (n = 26) and subpectoral group (n = 39), the mean number of days (81.46 days versus 88.64 days, p = 0.365) and mean number of visits (5.08 versus 5.69, p = 0.91) required to complete expansion exhibited no significant differences. Additionally, there were no significant differences in the mean amount of postoperative expansion (314.23 mL versus 315.38 mL, p = 0.950), the mean final volume (353.08 mL versus 339.62 mL, p = 0.481) or the mean final volume ratio (0.89 versus 0.86, p = 0.35) between the two groups. Therefore, we suggest that prepectoral tissue expander placement after conventional mastectomy can be a valid option.