Quantity of lymph nodes correlates with improvement in lymphatic drainage in treatment of hind limb lymphedema with lymph node flap transfer in rats.

Purpose: This study was conducted to investigate the correlation between the number of vascularized lymph nodes (LN) transferred and resolution of hind limb lymphedema in a rat model.

Methods: Unilateral hind limb lymphedema was created in 18 male Sprague-Dawley rats following inguinal and popliteal LN resection and radiation. A para-aortic LN flap based on the celiac artery was subsequently transferred to the affected groin. The three study groups consisted of Group A (no LN transfer), Group B (transfer of a single vascularized LN), and Group C (transfer of three vascularized LNs). Volumetric analysis of bilateral hind limbs was performed using micro-CT imaging at 1, 2, and 3 months postoperatively. Lymphatic drainage was assessed with Tc(99) lymphoscintigraphy preoperatively and at 3 months postoperatively.

Results: A statistically significant volume reduction was seen in Groups B and C compared to Group A at all time points. Volume reduction of Group A vs.Group B at 1 month (8.6% ± 2.0% vs. 2.7% ± 2.6%, P < 0.05), 2 months (9.3% ± 2.2% vs. -4.3% ± 2.7%, P < 0.05), and 3 months (7.6% ± 3.3% vs. -8.9% ± 5.2%, P < 0.05). Volume reduction of Group A vs. Group C at 1 month (8.6% ± 2.0% vs. -6.6% ± 3.1%, P < 0.05), 2 months (9.3% ± 2.2% vs. -10.2% ± 4.6%, P < 0.05), and 3 months (7.6% ± 3.3% vs. -9.1% ± 3.1%, P < 0.05). Of note, comparison of Groups B and C demonstrated greater volume reduction in Group C at 1 (P < 0.02) and 2 (P = 0.07) months postoperatively.

Conclusions: LN flap transfer is an effective procedure for the treatment of lymphedema. The number of vascularized LNs transferred correlates positively with the degree of volume reduction.