Prepectoral Direct-to-Implant Breast Reconstruction: Safety Outcome Endpoints and Delineation of Risk Factors

Background: Continued evolution of implant-based breast reconstruction involves immediate placement of the implant above the pectoralis muscle. The shift to prepectoral breast reconstruction is driven by goals of decreasing morbidity such as breast animation deformity, range-of-motion problems, and pain, and is made possible by improvements in mastectomy skin flap viability. To define clinical factors to guide patient selection for direct-to-implant prepectoral implant reconstruction, this study compares safety endpoints and risk factors between prepectoral and subpectoral direct-to-implant breast reconstruction cohorts. The authors hypothesized that prepectoral direct-to-implant breast reconstruction is a safe alternative to subpectoral direct-to-implant breast reconstruction. Methods: Retrospective chart review identified patients who underwent prepectoral and subpectoral direct-to-implant breast reconstruction, performed by a team of five surgical oncologists and two plastic surgeons. Univariate analysis compared patient characteristics between cohorts. A penalized logistic regression model was constructed to identify relationships between postoperative complications and covariate risk factors. Results: A cohort of 114 prepectoral direct-to-implant patients was compared with 142 subpectoral direct-to-implant patients. The results of the penalized regression model demonstrated equivalence in safety metrics between prepectoral direct-to-implant and subpectoral direct-to-implant breast reconstruction, including seroma (p = 0.0883), cancer recurrence (p = 0.876), explantation (p = 0.992), capsular contracture (p = 0.158), mastectomy skin flap necrosis (p = 0.769), infection (p = 0.523), hematoma (p = 0.228), and revision (p = 0.122). Conclusions: This study demonstrates that prepectoral direct-to-implant reconstruction is a safe alternative to subpectoral direct-to-implant reconstruction. Given the low morbidity and elimination of animation deformity, prepectoral direct-to-implant reconstruction should be considered when the mastectomy skin flap is robust.