Fig. 3From: A retrospective and prospective study to establish a preoperative difficulty predicting model for video-assisted thoracoscopic lobectomy and mediastinal lymph node dissectionBox plots showed four significantly different variables including FEV1/pred FEV1 (a), FEV1/FVC (b), mediastinal lymph node enlargement or calcification (c) and prior lung disease (d) for two groups in a training setBack to article page