Effects of autotransplanted lymph node fragments on the lymphatic system in the pig model.

Secondary lymphedema often develops after removal of lymph nodes in combination with radiation therapy, in particular in patients with breast cancer, inguinal cancer, cervical cancer and melanoma. No convincing treatment for the prevention and therapy of acquired lymphedema exists so far, therefore we wanted to show the reintegration of transplanted avascular lymph node fragments in the lymphatic system and positive effects of the transplanted fragments on the restoration of the lymphatic flow in this study. A total of 26 minipigs underwent lymphadenectomy of both groins. A minimum of one lymph node was retransplanted. The lymph nodes were cut into small pieces and retransplanted in the left groin (n = 17) or in both groins (n = 9). Different retransplantation techniques were investigated, transplantation of large versus small fragments, with and without capsule. The lymph flow was evaluated 5 and 8 months after surgery, using SPECT/CT and Berlin Blue. The results were confirmed by dissection. The lymph node transplants were assessed histologically. In contrast to the lymph flow in the transplanted groin, the lymph flow in the non-transplanted groin was often malfunctioning. Large lymph node fragments were found reintegrated in the lymphatic system more often than small slices of lymph node fragments. About 5 months after surgery impairment of lymph flow was seen especially after retransplantation of small slices of lymph node fragments. In seven out of eight minipigs a dermal backflow developed in the non-transplanted groin, 8 months after surgery. Only one minipig of these groups developed dermal backflow in both groins. All lymph node fragments showed an organized structure histologically. Autologous lymph node transplantation has positive effects on the regeneration of lymph vessels and restoration of lymph flow after lymphadenectomy.