Direct to Implant Extracellular Matrix Hammock Based pre-or Retropectoral Breast Reconstruction

Women diagnosed with breast cancer, large areas of ductal carcinoma in situ or a hereditary high risk of breast cancer are offered a mastectomy either as a therapeutic or a risk reducing intervention. Those, who are found eligible for an immediate breast reconstruction using an implant are reconstructed by either a skin sparing mastectomy (SSM) or a nipple sparing mastectomy (NSM) using an extracellular matrix. The current technique is to place the implant in a retropectoral pocket in which the cranial part of the implant is covered by the major pectoral muscle, whereas the caudal part of the implant is covered and supported by an extracellular dermal matrix (ADM) as a hammock.

Recent focus on the functional outcome has, however, identified a new challenge - breast animation deformity (BAD), breast distortion or "jumping breast". The consequence of the condition is that women with aesthetic pleasant results, in rest, experience breast animation deformity during contraction of the major pectoral muscle. Evaluation of forty breast augmented women with a subpectoral positioning of the implant revealed that 77.5% had some kind of distortion during movement of the arm. In these healthy individuals, however, the condition is partly hidden by the glandular tissue and subcutaneous fatty tissue.

The condition is more severe in women with a reconstructed breast using a retropectorally placed implant, where the glandular tissue has been removed, leaving only the subcutaneous fatty tissue to cover the muscle and implant. The investigators know from experience and from reviewing unpublished clinical pictures and videos of thirty patients, who had an immediate breast reconstruction using the hammock technique, that the vast majority of patients have a pronounced degree of BAD.

Patients, who have a prepectoral placement of their implant, tend to have a lesser degree of BAD. The functional outcome of the prepectoral placement of the implant has previously not been compared to the retropectoral placement of the implant in women reconstructed by an implant and an ADM. A possible disadvantage of a prepectoral placement of the implant may be less soft-tissue coverage supplied by the pectoral muscle leading to higher risk of significant capsular formation. Less soft-tissue coverage may also result in a more visible implant border and rippling. Furthermore, the implant will not benefit from the abundant vascularity of the muscle and in theory perhaps not be as resistant to infections and implant loss as the subpectoral positioned implants.

The primary aim of this study is to compare the degree of BAD following a prepectoral to a retropectoral placement of the implant using the hammock for immediate breast reconstruction. For this purpose we have designed two separate trials: