Comparing outcomes of prepectoral, partial muscle-splitting subpectoral, and dual-plane subpectoral direct-to-implant reconstruction: implant upward migration and the pectoralis muscle.

Background: Although dual-plane subpectoral breast reconstruction has been widely implemented in implant-based breast reconstruction, animation deformities remain an issue. Recent advances in skin flap circulation detection have increased the use of prepectoral reconstruction. A partial muscle-splitting subpectoral plane was introduced to decrease the visibility of the implant edge. However, there is yet to be a direct comparison of these methods for optimal results, including changes in implant position after reconstruction. This study aims to compare the incidence of complications such as rippling, animation deformity, implant upward migration between the dual-plane, the partial muscle splitting subpectoral and the prepectoral reconstruction group. In addition, multivariate analysis was conducted to identify the risk factors of complications.

Methods: We retrospectively investigated 349 patients who underwent unilateral direct-to-implant breast reconstruction from January 2017 to October 2020. Implants were inserted into the dual-plane subpectoral (P2) or partial muscle-splitting subpectoral (P1, the muscle slightly covering the upper edge of the implant) or the prepectoral pocket (P0). Postoperative outcomes and at least 2 years of follow-up complications were compared.

Results: There was no significant difference in rippling (P=0.62) or visible implant edges on the upper pole (P=0.62) among the three groups. In contrast, the P0 group had a lower incidence of seroma (P=0.008), animation deformity (P<0.001), breast pain (P=0.002), and upward implant migration (P0: 1.09%, P1: 4.68%, P2: 38.37%, P<0.001). According to the multivariate analysis, P2 resulted in a greater risk of seroma (odds ratio: 4.223, P=0.002) and implant upward migration (odds ratio: 74.292, P<0.001) than did P0.

Conclusions: P0 and P1 showed better postoperative outcomes than P2. Additionally, P0 had less implant migration than P1. Even though P1 minimally dissects the muscle, the location of the implant may change. Considering that muscle contraction can deteriorate symmetry and aesthetic results, the P0 method may be the most favorable.