Evaluation of lymphatic drainage in free flaps by lymphoscintigraphy: a preliminary study

Lymphatic drainage from free flaps was studied by lymphoscintigraphy in 14 patients in whom free vascularised flaps were used to cover defects caused by trauma or tumour ablation. Lymphoscintigrams were done after intradermal injection of Technetium-99m-Dextran in the flap and in the corresponding contralateral normal area. The retention of radioactivity at the injection sites after 1 h was computed and expressed as percentages of baseline activity at the time of injection. 25 studies were done in 14 patients at intervals varying from 9 days to 6 years postoperatively. In all cases, radioactivity was detected beyond the flaps in the lymphatic channels and draining lymph nodes. There was no significant difference (P = 0.27) between the retention of activity in the flaps (mean 88.68%; s.e.m. 1.25) and that in the corresponding contralateral control area (mean 86.88%; s.e.m. 1.35). This study shows that lymphatic drainage in a free flap is established early after surgery.