Postoperative complications after subpectoral versus prepectoral implant-based breast reconstruction: A target trial emulation study

BACKGROUND: Subpectoral implant placement has traditionally been favored in implant-based breast reconstruction owing to concerns regarding soft tissue coverage. Advances in surgical techniques and use of acellular dermal matrix have increased interest in prepectoral placement, but more evidence on postoperative complications is needed. We compared complication rates between prepectoral and subpectoral implant placement using target trial emulation. METHODS: We included patients who underwent implant-based breast reconstruction at three Danish hospitals between 2018 and 2024. Outcomes were obtained from medical records and analyzed using double robust target trial emulation methods. The primary outcome was implant loss within two years. Secondary outcomes included implant-associated infection, hematoma, and mastectomy skin flap necrosis. RESULTS: A total of 940 patients (1398 breasts) were included. Implants were placed in 439 breasts (31%) in the prepectoral plane and 959 (69%) in the subpectoral plane. The 2-year risk of implant loss was 8.4% in the prepectoral group and 7.1% in the subpectoral group (risk difference: 1.3%, P = 0.67). No significant risk differences were found for implant-associated infection (2.8%, P = 0.38) or hematoma (0.5%, P = 0.76). Mastectomy skin flap necrosis was significantly higher in the subpectoral group (3.4%, P = 0.006). CONCLUSION: Prepectoral and subpectoral implant placement showed comparable risks of implant loss, implant-associated infection, and hematoma. The risk of mastectomy skin flap necrosis was higher in the subpectoral group. These results indicate that both approaches are comparably safe in terms of postoperative complications recorded in this study among eligible patients.