Anatomical Effects of Axillary Nodes Dissection on Rat Lymphatic System Model: Indocyanine Green Mapping and Dissection

BACKGROUND: Axillary nodes dissection (AND) is an important risk factor for the appearance of breast cancer-related lymphedema (BCRL). The anatomy and pathophysiology leading to the development of BCRL after AND are not completely understood. Despite the existence of lymphedema models after AND, none of them were able to create lymphedemas without additional chemical inflammatory drugs or auxiliary physical techniques (radiotherapy). In this study, we aimed to describe the anatomical changes of AND on a rat's front leg before and after a new surgery technique.

METHODS AND RESULTS: AND was performed on seven Wistar rats with a new, posterior surgical approach. Indocyanine green mapping was done before and after surgery to detect "normal and secondary superficial lymphatic pathways" of the operated rat's front legs. Twelve months after surgery, dissections were performed. Subcutaneous blue dye injection of the hand was used to observe superficial and deep lymphatic pathways. Postsurgery, an acute edema of arm and shoulder appeared and persisted for 14-21 days. However, none of the rats showed a chronic secondary lymphedema. In two cases, seromas also appeared. All rats showed substitution functional lymphatic pathways as perforating lymph vessels around the surgical sites.

CONCLUSION: This is the first description of perforating lymph vessels as lymphatic substitution pathways after AND on rats. These results help to understand why a chronic secondary lymphedema could not be created in rats after AND without additional chemical or physical interventions.