Outcomes of ADM-Assisted Implant-based Breast Reconstructions According to Division Types of the Pectoralis Major Muscle

In implant-based breast reconstruction (IBR), several surgical techniques are based on the implant insertion planes. Ideal location for breast implants has become a popular topic in IBRs because each technique has advantages and disadvantages. Herein, we report the outcomes of three different division types of the pectoralis muscle and suggest an algorithm for selecting the division types.

Charts of patients who underwent IBRs between October 2017 and December 2020 were retrospectively reviewed. The patients were classified into three groups (prepectoral, high subpectoral, and subpectoral) according to the division types of the pectoralis muscle. Aesthetic outcomes were assessed in terms of animation deformity, rippling deformity, and visibility of the upper implant border.

Total 104 cases were included. 25, 38, and 41 were in the prepectoral, high-subpectoral, subpectoral IBR groups, respectively. Animation deformities frequently appeared in the subpectoral group. Nipple displacement was most prominent in the subpectoral group. Skin rippling at rest was mostly detected in the prepectoral group, whereas ripping during contraction was commonly observed in the subpectoral group. Visibility of upper border was more prominent in the prepectoral group than the other groups.

We propose an algorithm for selecting the division types of the pectoralis muscle. If the pectoralis muscle is thick, prepectoral plane is most preferred to avoid the animation deformity. In cases with thin pectoralis muscle, thickness of the mastectomy flap is considered next. If it is thicker than 1cm, prepectoral plane is better than the subpectoral plane; otherwise, high-subpectoral plane is preferable for better aesthetic outcomes.

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266