Tissue Expander Overfilling: Achieving New Dimensions of Customization in Breast Reconstruction

Breast cancer remains the most common malignancy in woman with almost 300,000 new cases diagnosed in 2013.1 Of these cases, it is estimated that 20–40% of women who undergo mastectomy will elect to have breast reconstruction through either implant-based breast reconstruction or autologous tissue–based reconstructive method.2–5 Recent data have demonstrated that although the rate of autologous tissue–based breast reconstruction has remained relatively constant, implant-based reconstruction rates have risen by approximately 203%.5 In fact, in 2013, plastic surgeons in the United States performed a total of 95,589 breast reconstruction procedures, of which 68,607 (72%) involved tissue expansion for the reconstructive process.6 Therefore, tissue expander–based reconstruction represents the dominant modality of breast reconstruction in the United States. Breast reconstruction seeks to recreate the natural aesthetic of the breast after mastectomy. Success depends on a final outcome that produces pleasing breast contour and projection within the confines of the patient’s natural anatomy.7,8 Reconstructive surgeons routinely utilize a 2-staged approach characterized by initial tissue expander placement to create and maintain tissue pockets that will be eventually utilized for implant-based or autologous tissue–based reconstructions. Although many methods can be used to tailor the pocket at the second stage of reconstruction, these often cannot fully correct an initial pocket that is less than ideal.9 Surgeons must choose tissue expanders from a set catalogue of available devices with restricted dimensions. These expanders have set base widths and projections for each volume within a given style. Therefore, expander reconstructions must balance base diameter, volume, and projection—often sacrificing shape in 1 dimension for the betterment of others. Furthermore, although a tissue expander is placed with a certain result in mind, during expansion, volumes are often adjusted to meet changes in patient preference or simply to obtain the initially desired outcome. As replacement of one expander style with another requires another operative procedure, patient’s tissue pockets are often confined to the expansion parameters dictated by the expander’s inherent dimensions. To ameliorate this limitation, reconstructive surgeons often overfill tissue expanders to increase breast volume or redefine the mastectomy pocket without exchange of the initial expander. Although no data on the prevalence of overfilling breast tissue expanders are published, this technique is commonly used.9 Overfilling of the expander leads to increased breast volume; however, its effects on the overall shape of the expander have not been examined. Toward this end, this study sought to address how tissue expander overfilling affects expander dimensions with increasing volume. It is our belief that determination of expander hyperinflation dynamics may better inform efforts to create truly customized dimensions for ideal mastectomy pocket creation, thereby improving the end results that may be achieved for expander-related breast reconstruction.