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. 24.3% +/- 2.7%, P<0.05), and 3 months (7.6% +/- 3.3% vs. 28.9% +/- 5.2%, P<0.05). Volume reduction of Group A vs. Group C at 1 month (8.6% +/- 2.0% vs. 26.6% +/- 3.1%, P<0.05), 2 months (9.3% +/- 2.2% vs. 210.2% +/- 4.6%, P<0.05), and 3 months (7.6% +/- 3.3% vs. 29.1% +/- 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. (C) 2015 Wiley Periodicals, Inc.