Pre-Operative Mammography as a Predictor of Mastectomy Skin Flap Necrosis

Introduction: Breast cancer is a common diagnosis with mastectomy a common treatment modality. Mastectomy skin flap necrosis (MSFN) occurs when the blood supply to the skin flaps is insufficient to meet metabolic demands. We sought to determine whether mammography would aid in preoperative risk stratification of patients hypothesizing that a thicker subcutaneous adipose tissue layer would be associated with a lower rate of postoperative MSFN. 

Methods: A prospectively maintained database was retrospectively analyzed to identify 50 consecutive patients who underwent nipple sparing mastectomy (NSM) and subsequent implant based or autologous breast reconstruction. Using each patient’s preoperative mammography, measurements were made to determine the thickness of the subcutaneous tissue.  This was performed by taking an average of six measurement points. Three points were obtained on the craniocaudal view and three on the medial lateral oblique view. 

Results: Forty-four patients and 73 breasts were included in final data analysis. Forty-three (58.9%) patients experienced mastectomy flap necrosis. On multivariable regression, subcutaneous thickness (p = 0.04) was found to be predictive of mastectomy skin flap necrosis along with BMI (p = 0.02) and smoking status (p=0.02). 

Conclusion: A significant association between subcutaneous tissue thickness and MSFN was identified. Two hypotheses are proposed; 1) the subdermal plexus in patients with thinner subcutaneous tissues is less robust, and 2) the subdermal plexus is more easily disrupted mechanically intraoperatively in patients with thinner subcutaneous tissues. Further studies may be aimed at determining if there is a specific value beyond which mastectomy skin flap necrosis can be expected.