Anatomic Support for Hand and Wrist Dye Injections in Axillary Reverse Mapping.

Background: Axillary reverse mapping (ARM) identifies lymph vessels and nodes draining the arm to preserve them during axillary lymph node dissection (ALND) and thus reduce the risk of breast-cancer related lymphedema (BCRL). The ideal location for dye injections has not been previously studied. This study compared transected lymphatic vessels visualized for immediate lymphatic reconstruction (ILR) after ALND between patients who received fluorescein isothiocyanate (FITC) injections in the hand/wrist and those who received traditional medial upper-arm location.

Methods: A retrospective review of ILR patients from September 2017 through May 2023 was performed. Dye injection site, number of channels visualized, channel distances from the axillary vein (cm), and channel diameters (mm) were collected. A chi-square test was used to compare the number of channels between injection sites. Mann-Whitney U tests were used to compare channel distances and channel diameters between injection sites.

Results: Of 323 patients, 180 received hand/wrist injections, and 143 received medial upper-arm injections. Altogether, 755 channels were visualized. Fewer lymphatic channels were visualized in the hand/wrist injection group (p = 0.011). The median channel distance from the axillary vein was 2.3 cm after hand/wrist injections and 2.7 cm after medial upper-arm injections (p < 0.001). Channel diameters did not differ between injection-site groups (p = 0.066).

Conclusions: With the hand/wrist injections, fewer channels closer to the axillary vein were visualized. These findings corroborate prior anatomic and intraoperative studies identifying main lymphatic vessels of the arm as traveling closely along the axillary vein. Hand/wrist injections are more likely to identify main lymphatic channels draining the arm when ARM is performed.