Investigation of lymphatic system restructuring after facial transplants containing different tissue components

A functional lymphatic system is essential for maintaining body fluid homeostasis and immune cell functions. Traumas of regional lymphatics cause chronic lymphedema, recurrent infection, loss of function and decrease in quality of life. Although direct repair of the lymphatic system is not performed in reconstructions with free flaps, extremity replantations, extremity transplantations or face transplants, lymphedema is observed to be absent or minimal in the tissues. Although this observation leads to conclusions that the restructuring of the lymphatic system occurs during wound healing spontaneously, its mechanism and which lymphatic pathways it uses are not fully understood. Changes in lymphatic structures and related lymphodynamics are important for understanding the lymphatic system of donor and recipient tissue interaction. Advances in indocyanine green (ICG) lymphography methods in lymphatic imaging have allowed better assessment of lymphatic transport. However, communication and functional and regenerative capacities of recipient and donor lymphatics are still not fully elucidated. The aim of this study is to examine lymphatic remodeling and regeneration in facial reconstruction with facial transplants and free flaps without lymphatic anastomosis. Face transplant patients who were operated between 01.01.2012 and 01.01.2022 in the Plastic, Reconstructive and Aesthetic Surgery clinic of Akdeniz University Faculty of Medicine were included in the study. ICG lymphography images of these patients were evaluated. ICG lymphography images of patients underwent facial reconstruction with supraclavicular free flap and patients with maxillofacial fractures who underwent reconstruction without flaps were used as control group. ICG lymphography of the face was performed by injecting 0.2 mL of ICG solution (0.5 mg ICG) subcutaneously into 8 distinct locations of the face, including supraorbital area, infraorbital area, oral commissure, and mental area bilaterally, in accordance with the manufacturer's recommendations and in accordance with the current literature. The images obtained were evaluated within the scope of this study. ICG lymphography images were evaluated as linear and reticular in the transient phase, and as linear, splash, stardust and diffuse patterns in the plateau phase. After the completion of the 3-hour ICG lymphography, the observed patterns were examined by drawing on the patients' skin. Lymphedema was evaluated as absent or mild in face transplant patients, mostly linear pattern was observed in ICG lymphography, and an increase in superficial lymphatics was observed. Multiple lymphatic connections were observed between the recipient and donor tissues, and ICG was observed in the cervical lymph nodes. In one patient who underwent reconstruction with free supraclavicular flap, mild lymphedema was observed, while the other patient had moderate lymphedema. Although stardust pattern was observed in both patients in ICG lymphography, multiple lymphatic connections were observed between the recipient and donor tissues in this patient group, and ICG was observed in the cervical lymph nodes. Although lymphatic anastomosis was not performed, spontaneous lymphatic connections were demonstrated in patients who underwent facial reconstruction with face transplantation or free supraclavicular flap.