Incidence of the superficial fascia and its relevance in skin-sparing mastectomy.

BACKGROUND: With the move away from classical radical mastectomy to ever more skin-sparing procedures, there has been an ongoing discussion about how much skin and subcutaneous tissue should be resected to perform an adequate mastectomy while leaving viable skin flaps. One of the common recommendations is to dissect just superficial to the superficial layer (SL) of the superficial fascia of the breast. This, in turn, has revived the old, unsolved controversy about the existence or absence of the SL, a fascia that reportedly encloses the mammary gland ventrally. In skin-sparing mastectomies (SSM), which combine tumor resection with immediate breast reconstruction, the ideal would be to create skin flaps that are thin enough to remove all breast tissue but at the same time are thick enough to preserve flap circulation. The feasibility of meeting these two goals simultaneously and the possible role and relevance of the SL as a guide to dissection in SSM was examined in this study.
METHODS: Sixty-two breast resection specimens from 31 women who underwent breast reduction were examined histologically to determine whether the SL was present, whether breast tissue could be detected within or beyond this SL, the measured distance between the caudal border of the dermis and the SL or the breast tissue, and whether the thickness of the subcutaneous fat layer was correlated with the patients' physical data, such as body weight or body mass index (BMI).
RESULTS: The SL was absent in 44% of resection specimens. When the SL was present, 42% of specimens contained several islands of breast tissue within the SL. No breast tissue was found beyond the SL. The minimal distance between the SL and the dermis varied from 0.2 mm to 4.0 mm; the minimal distance between the breast tissue and the dermis was 0.4 mm. In 50% of specimens, the minimal distance between the dermis and the SL or breast tissue was < 1.1 mm. A distance of > or = 5 mm was encountered in only 17% of specimens, and a distance of > or = 10 mm was encountered in only 5% of specimens. No significant correlation between the right and left breast was found with any of the parameters examined. A weak negative correlation was seen between the BMI and the mean thickness of the subcutaneous fat (P = 0.049; correlation coefficient [r] = -0.39; Spearman rank correlation).
CONCLUSIONS: Histologic evaluation revealed that the SL is not present in all breasts and, thus, cannot serve as a reliable plane of dissection. Furthermore, if the SL is present microscopically, then it often is too thin and delicate to be detectable macroscopically. Finally, even if the SL is present and visible macroscopically, the distance to the overlying skin is so small in the majority of patients that a dissection superficial to the SL would not leave viable skin flaps in skin-sparing mastectomies. Copyright 2002 American Cancer Society.