THE UPPER ARM LYMPHOSOME: WATERSHED OF UPPER ARM LYMPHATIC PATHWAYS EVALUATED WITH INDOCYANINE GREEN LYMPHOGRAPHY

Understanding lymphatic anatomy of the upper extremity is necessary for treatment of upper extremity lymphedema (UEL). This study aimed to clarify the watershed of upper arm lymphosomes using fluorescent lymphography with multi-site injection of indocyanine green (ICG). Limbs contralateral to breast cancer treatment side of breast cancer survivors were included to evaluate upper arm lymphosomes. 0.1ml of ICG was injected intra-dermally at these 3 points in the mid-lateral upper arm: at the level of one (U1), two (U2), and three quarters (U3) from the lateral edge of the acromion to the lateral epicondyle of the humerus. Fluorescent images were obtained to determine the upper arm lymphatic pathway patterns. An injection site with multiple lymphatic pathways was evaluated as a watershed point. A total of twenty-one limbs were included. The lymphatic pathways from the U1/ U2/ U3 were anteromedial patterns in 20/13/6 (95.2%/90.5%/28.6%), and posterolateral pat-terns in 3/13/19 (14.3%/61.9%/90.5%), respectively. Both patterns were identified in 2/12/5 (9.5%/57.1%/23.8%), and no pattern in 0/1/1 (0%/4.8%/4.8%). Based on study results, the true watershed was determined as an approximate line from the posterolateral side of the lateral edge of the acromion to the anteromedial side of the lateral epicondyle of the humerus rather than a mid-arm line.