Effects of Subcutaneous versus Submuscular Tissue Expander Placement on Breast Capsule Formation

In autologous breast reconstruction, skin envelope reconstruction is especially important given the flexibility of new breast parenchyma. Our experience suggests a better control of breast shape with subcutaneous tissue expander (TE) placement compared with submuscular TE placement. We speculate that capsule formation might be different in subcutaneous TE placement compared with submuscular TE placement. To elucidate this hypothesis, we collected capsules formed around the TE in two-stage breast reconstruction patients and evaluated differences in histology and capsule wall thickness between subcutaneous (n = 7) and submuscular (n = 8) TE placement. Our findings show that subcutaneous TE placement results in thinner capsule formation with low vascularity when compared with submuscular TE placement (354 ± 96 μm and 589 ± 92 μm, respectively; P < 0.001). Because thin connective tissue can reduce postoperative shrinkage of the skin envelope, it would be beneficial to predict and control the shape of reconstructed breast. Although further study is needed, differences in vascularity between subcutaneous tissue and muscle might affect the thickness of capsules.