Safety of Brand Discordant Tissue Expanders and Implants in Staged Breast Reconstruction

Introduction: – Device manufacturers generally recommend using concordant tissue expanders (TE) and implants during staged implant-based breast reconstruction (IBBR). In practice, discordant pairings may occur due to availability, patient or surgeon preference, or intraoperative considerations, but the impact of such mismatches on outcomes remains unclear. Methods: – Consecutive TE-to-implant exchanges (2018–2023) across nine surgeons at a quaternary cancer center were retrospectively reviewed. Patients were categorized as concordant or discordant based on manufacturer match. Propensity score matching minimized preoperative differences. Outcomes included surgical complications, implant-related morbidity, and revision procedures. Results: – Among 496 exchanges, 330 (67%) were concordant and 166 (33%) discordant. Discordance was most frequent between Mentor and Allergan devices. Unmatched analyses showed similar overall complications (5.2% vs. 7.2%, p=0.35) and comparable rates of infection, seroma, and malposition. Revisions occurred in 14% of concordant and 18% of discordant cases (p=0.23), with mastopexy (0% vs. 4.2%, p<0.001), new implant placement (2.7% vs. 7.8%, p=0.009), and capsulotomy/capsulorrhaphy (0.6% vs. 3.0%, p=0.045) more frequent in discordant exchanges. After propensity score matching (n=135 per group), outcomes remained balanced, including overall complications (5.9% vs. 6.7%, p=0.80) and revision rates (19% vs. 16%, p=0.42). Conclusions: – Discordant TE–implant pairings are safe and do not increase complications or revision risk after adjustment for baseline factors. These results suggest that patient and treatment characteristics, rather than manufacturer concordance, are the primary determinants of outcomes in staged IBBR.