Background/Objectives: To quantitatively assess the long-term volume stability of acellular dermal matrix (ADM) in oncoplastic breast-conserving surgery (OBCS) and analyze surgical and aesthetic outcomes. Methods: This retrospective study examined 172 breast cancer patients who underwent OBCS with immediate ADM-based volume replacement (2020–2022). Patients received either diced ADM with sheet ADM (n = 102) or diced ADM with paste ADM (n = 70). The ADM volume was evaluated using MRI at 6, 12, and 24 months postoperatively. Results: Long-term volume stability was achieved in both groups with minimal volume reduction (4.3–4.5%) at 24 months (p < 0.001). Early surgical complications included hematoma (4.1%), seroma (2.3%), and wound issues (1.2%), with no infections or ADM non-incorporation. Contour irregularities occurred in 16.3% of cases. Radiotherapy (87% of patients) did not significantly impact ADM volume retention. Conclusions: ADM provides predictable, durable volume replacement in OBCS, with excellent volume stability even with radiotherapy. This quantitative assessment of ADM volume retention over two years supports ADM as a reliable option for breast-conserving surgery, potentially expanding treatment options for patients with unfavorable tumor-to-breast volume ratios.

Background and Objectives: Infections and capsular contractures remain unresolved issues in implant-based breast reconstruction. Capsular contractures are thought to be caused by the endogenous flora of the nipple duct. However, little is known about the antibiotic susceptibility of the microorganisms involved. This study aimed to evaluate the composition of endogenous breast flora and its antimicrobial susceptibility in patients with breast cancer. This study will aid in selecting a prophylactic antibiotic regimen for breast reconstruction surgery. Materials and Methods: We obtained bacteriologic swabs from the nipple intraoperatively in patients who underwent implant-based breast reconstruction following nipple-sparing mastectomy between January 2019 and August 2021. Antibiotic susceptibility tests were performed according to the isolated bacteriology. Statistical analysis was performed based on several patient variables to identify which factors influence the antibiotic resistance rate of endogenous flora. Results: A total of 125 of 220 patients had positive results, of which 106 had positive culture results for coagulase-negative Staphylococcus species (CoNS). Among these 106 patients, 50 (47%) were found to have methicillin-resistant staphylococci, and 56 (53%) were found to have methicillin-susceptible staphylococci. The methicillin resistance rate in the neoadjuvant chemotherapy group (56.3%) was significantly higher (OR, 2.3; p = 0.039) than that in the non-neoadjuvant chemotherapy group (35.5%). Conclusions: Based on the results, demonstrating high and rising incidence of methicillin-resistant staphylococci of nipple endogenous flora in patients with breast cancer compared to the past, it is necessary to consider the selection of prophylactic antibiotics to reduce infections and capsular contracture after implant-based breast reconstruction.

Background: Prepectoral breast reconstruction with an acellular dermal matrix (ADM) typically requires intraoperative manual tailoring, introducing structural variability and workflow delays. We developed the Polyhedral Matrix Configuration (PMC) technique—a geometric method for standardizing ADM shell creation—and compared it to our traditional “tear-drop” wrap to determine whether standardization improves structural integrity and operative efficiency. Methods: We reviewed all consecutive 227 patients undergoing immediate prepectoral reconstruction from January 2021 to December 2024 (tear-drop group: n = 155; PMC group: n = 72). PMC transforms planar ADM into a 3D dome using pre-designed wedge resections and butt-joint sutures, eliminating material overlap. Standardization permits back-table fabrication during mastectomy (“parallel two-team workflow”). We excluded bilateral cases for consistent operative time assessment and performed subgroup analysis to control for higher robotic mastectomy rates in the PMC cohort. Results: PMC reduced the plastic surgery time by a mean of 44.6 min (95% CI: 35.2–54.0) (p < 0.001), with subgroup analysis confirming efficiency gains across both conventional (32.8 min, 95% CI: 20.1–45.5, p < 0.001) and robotic mastectomies (60.8 min, 95% CI: 47.3–74.3, p < 0.001). Despite zero-overlap design, PMC showed no increase in major complications (p > 0.99) and lower rates of visible rippling (odds ratio 0.28, 95% CI: 0.08–0.97, p = 0.032). BREAST-Q “Satisfaction with Breasts” scores were higher in the PMC group (mean difference +7.3 points, 95% CI: 3.1–11.5, p = 0.001). Conclusions: Geometric standardization enables both design precision and operative efficiency. By separating reconstruction preparation from mastectomy through a reproducible protocol, PMC reduces the operative time while improving aesthetics through stable, single-layer construction.