Background: Vascularized groin lymph node flap transfer is an emerging approach to the treatment of postmastectomy upper limb lymphedema. The authors describe the pertinent flap anatomy, surgical technique including different recipient sites, and outcome of this technique. Methods: Ten cadaveric dissections were performed to clarify the vascular supply of the superficial groin lymph nodes. Ten patients underwent vascularized groin lymph node flap transfer for postmastectomy upper limb lymphedema using the wrist (n = 8) or elbow (n = 2) as a recipient site. Ten patients who chose to undergo physical therapy were used as controls. Intraoperatively, indocyanine green was injected subcutaneously on the flap margin to observe the lymph drainage. Outcomes were assessed using improvement of circumferential differentiation, reduction rate, and decreased number of episodes of cellulitis. Results: A mean 6.2 ± 1.3 groin lymph nodes with consistent pedicles were identified in the cadaveric dissections. After indocyanine injection, the fluorescence was drained from the flap edge into the donor vein, followed by the recipient vein. At a mean follow-up of 39.1 ± 15.7 months, the mean improvement of circumferential differentiation was 7.3 ± 2.7 percent and the reduction rate was 40.4 ± 16.1 percent in the vascularized groin lymph node group, which were statistically greater than those of the physical therapy group (1.7 ± 4.6 percent and 8.3 ± 34.7 percent, respectively; p < 0.01 and p = 0.02, respectively). Conclusions: The superficial groin lymph nodes were confirmed as vascularized with reliable arterial perfusion. Vascularized groin lymph node flap transfer using the wrist or elbow as a recipient site is an efficacious approach to treating postmastectomy upper limb lymphedema. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Background: Vascularized lymph node flap transfer for the treatment of upper and lower limb lymphedema has had promising results. This study was performed to investigate the mechanism of lymph drainage of a vascularized lymph node flap both experimentally and clinically. Methods: In the experimental study, 18 Sprague-Dawley rats were used to create 36 flaps, either a groin lymph node flap or an abdominal cutaneous flap that did not contain lymph nodes. Indocyanine green dye was injected into the edge of 12 lymph node flaps, directly into a lymph node of 12 lymph node flaps, and into the edge of 12 cutaneous flaps. In the clinical study, an identical study design was used, with 24 vascularized lymph node flaps and 12 cutaneous flaps not containing lymph nodes. Results: Experimentally, fluorescence was detected in the pedicle vein after a mean latency period of 153 ± 129 seconds when the edge of the lymph node flap was injected and 12.8 ± 8.1 seconds when the lymph node was directly injected. Fluorescence was not detected in the pedicle vein of the cutaneous flaps (p < 0.01). Clinically, fluorescence was detected in the pedicle vein after a mean latency period of 346 ± 249 seconds when the edge of the lymph node flap was injected and 23.5 ± 27.1 seconds when the lymph node was directly injected. Fluorescence was not detected in the pedicle vein of the cutaneous flaps (p < 0.01). Conclusion: The vascularized lymph node flap drains lymph into the pedicle vein, both experimentally and clinically. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.