Proposals for Changes in the Mountain and Dresler Mediastinal and Pulmonary Lymph Node Map

Staging of the intrathoracic mediastinal and pulmonary lymph nodes is one of the most important problems in the treatment of non-small cell lung cancer. The map of the mediastinal and pulmonary lymph nodes proposed by Clifton F. Mountain and Carolyn M. Dresler gained wide acceptance and has become a standard of staging. However, it has some shortcomings of clarity in the description of localization of specific nodal stations. In our opinion, some modifications of this map are necessary. Based on our experience with extended mediastinoscopy and the new procedure, transcervical extended mediastinal lympadenectomy, the main changes we propose are: 1) the left innominate vein as the anatomic separation between nodal stations 1 and 2; 2) the merging of station 2 and 4 in a single right and left paratracheal station; 3) the shift of the midline to the left paratracheal margin; 4) the tracheobronchial angles as the landmark between stations 4 and 10 bilaterally; 5) the separation of three nodal groups in the subcarinal area: subcarinal (number 7), peribronchial (number 10R and 10L), and periesophageal (number 8); 6) the merging of station 5 and station 6 nodes in a single station with the following landmarks: medial border: the midline, lateral border, the descending aorta and upper border: the left innominate vein and lower border: the lower margin of the left pulmonary artery; and 7) the definition of station 3A nodes as those in front of the superior vena cava.