Ultrasound-assisted CNSs Mapping Versus Dual-tracer-guided Sentinel Lymph Node Biopsy

1ml of CNSs was subcutaneously injected into the areolar area in the upper outer quadrant of the breast. The injection site was massaged for 15 minutes to promote drainage of the tracer to the axilla. During the intraoperative ultrasound-assisted procedure, an ultrasound diagnostic system was used. Before the incision, ultrasound-guided exploration of SLNs was performed by placing the probe on the lateral border of the breast and sliding cranially along the lateral border of the pectoralis major muscle . A sterile skin marker was then used to mark the optimal site of incision over the targeted lymph nodes, and the distance from the skin to the nodes was measured by ultrasound and recorded in millimeters. Blunt dissection was carried out to identify the CNSs-stained nodes around the marked region. Ultrasonography probe was placed repeatedly in or around the wound at different angles for adequate visualization if SLNs could not be localized with further dissection.

The preparation of CNSs mapping was identical to that of the UC group. 1ml of diluted ICG was subsequently injected into the areolar area in the upper outer quadrant of the breast. A NIR camera was used to visualize the subcutaneous lymph vessels and localized the SLNs. All fluorescent or black-stained lymph nodes along with any palpable suspicious nodes were removed. The remaining surgical field was reexamined to ensure complete resection of fluorescent lymph nodes.