Correlation between Quantity of Transferred Lymph Nodes and Outcome in Vascularized Submental Lymph Node Flap Transfer for Lower Limb Lymphedema

Background: Vascularized lymph node transfer (VLNT) has shown promising results in the treatment of lower limb lymphedema, but little is known about the number of lymph nodes needed for the transfer to achieve optimal results. This study investigated the correlation between number of transferred lymph nodes in submental VLNT and outcomes regarding limb circumference reduction and cellulitis incidence. Methods: Thirty-five patients who had received submental VLNT to an ankle for lower limb lymphedema, post-gynecological cancer treatment, were included in the study. Limb circumference was determined via tape measurement pre- and postoperatively and was used to calculate the circumferential difference. Ultrasonography was performed postoperatively to determine the number of lymph nodes within the transferred flap. Patients were divided into groups A-C depending on the number of transferred lymph nodes: 1-2 (n=10), 3-4 (n=14) and 5-8 (n=11), respectively. Results: The mean age was 60.0 ± 9.2 years. All flaps survived. The mean improvement of circumferential difference for the whole cohort was 19.8 ± 9.2 %. Groups B and C both had significantly higher improvements in the circumferential difference than group A (p=0.04 and p=0.02, respectively), but when compared to each other, the difference was non-significant. All groups had significant reductions in cellulitis incidence postoperatively. Conclusions: Submental VLNT for lower limb lymphedema reduced the incidence of cellulitis, regardless of the number of transferred lymph nodes. The transfer of 3 or more lymph nodes provided significantly better outcome regarding limb circumference reduction than the transfer of 2 or fewer lymph nodes. FINANCIAL DISCLOSURE STATEMENT: The authors have nothing to disclose. No funding was received for this article. AUTHOR CONTRIBUTIONS: JG and MHC were responsible for the study idea, design and follow-through. JG, SYC and WHC were responsible for data collection. All authors were involved in the interpretation of results. JG and MHC were responsible for statistical analysis. All authors were involved in critical review and approval of the final result. IRB NUMBER: 101-3481B ACKNOWLEDGMENTS: The authors would like to thank Miffy Chia-yu Lin, M. Sc., for her assistance in the preparation of tables and figures for this manuscript. CORRESPONDING AUTHOR: Ming-Huei Cheng, MD, MBA, FACS, Division of Reconstructive Microsurgery, Department of Plastic and Reconstructive Surgery, Center of Tissue Engineering, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, No. 5 Fu-Hsing Street, Kweishan, Taoyuan 333, Taiwan , Telephone: +886 3 281200 ext. 2172, Fax: +886 3 3972681, E-mail: minghueicheng@gmail.com, minghuei@adm.cgmh.org.tw ©2018American Society of Plastic Surgeons