Intraoperative Imaging of Mastectomy Skin Flaps for Breast Reconstruction

The most common complication following mastectomy and prosthetic reconstruction is mastectomy skin flap necrosis due to an inadequacy of tissue perfusion and hypoxia, with incidence rates up to ~20%1, 2. This violation of the skin envelope can lead to infection, implant exposure, implant loss, and the need for reoperation. Intraoperative prediction of skin flap necrosis area/volume allows for the guidance of compromised tissue removal to minimize skin flap necrosis and consequent complications. Current approaches to intraoperatively assess mastectomy skin flap are subjective and unreliable and rely largely on surgeon’s assessments of skin flap color, capillary refill, temperature, turgor, and dermal bleeding1, 2. Intraoperative fluorescence angiography is an adjunctive method involving intravenous injection of fluorescent dyes to assess blood perfusion on mastectomy skin flap surface (1 to 2 mm depth)2-7, which, however, may not adequately reflect blood flow throughout mastectomy skin flap depth (possibly up to 10 mm). Also, fluorescence angiography depends on a time window following dye injection as well as excitation light intensity, which may vary over subjects leading to measurement uncertainty. Aside from documented allergic reactions and invasive nature of fluorescent dye, fluorescence angiography methods have been shown to significantly under- or over-predict the areas of mastectomy skin flap necrosis4, 20. Finally, these methods primarily measure tissue blood perfusion, which may not always correlate with tissue blood oxygenation, another key factor affecting flap necrosis.