Patients, diagnosed as oromaxillofacial tumor and undergoing elective free fibular or anterolateral thigh flap reconstruction, were divided into two groups in a randomized, double-blind fashion. For patients with free fibular flaps harvested, femoral nerve block and common peroneal nerve with ropivacaine were administered. For patients with anterolateral thigh flaps harvested, femoral nerve block with ropivacaine was administered.In Group R, nerve blocks were administered with 0.3% ropivacaine. In Group RD, nerve blocks were administered with 0.3% ropivacaine and 50 μg dexmedetomidine.The primary endpoints were the onset time and duration of sensory blocks. The secondary endpoints were heart rate, blood pressure, pulse oxygen saturation (SpO2), sedation level, the duration of motor blocks.