Objective: Removing or sampling lymph nodes from the bilateral paratracheal area through a left thoracotomy is not a standard procedure in patients with lung cancer. The aim of this study was to evaluate the feasibility of a technique without ductus arteriosus division and mobilization of the aortic arch and to compare the number of lymph nodes resected in left-sided dissections to the number of lymph nodes removed in right-sided mediastinal dissections that are routinely performed in clinical practice. Methods: A total of 93 patients with hilar lung cancer were evaluated. A prospective study was conducted on 51 patients with primary left-sided hilar lung cancer, who underwent left thoracotomy and paratracheal lymphadenectomy between January 2008 and January 2010. The number of nodes dissected in these patients was compared with the number of nodes dissected in 42 patients with right-sided hilar lung cancer by right-sided mediastinal dissection within the same period. Results: The mean number of resected nodes in the bilateral paratracheal area via left thoracotomy was 8.4 (2-18 nodes). The distribution from 4R-4L-2L-2R was as follows: 3.3-2.5-0.5-2.1, respectively. Six patients (11.7%) were diagnosed with occult N2, and two (3.9%) of these patients also had N3 disease concomitantly. The number of dissected nodes from the ipsilateral station 2 via right-sided versus left-sided thoracotomy was 1.6 versus 0.5 (p = 0.000), whereas the number of dissected nodes from ipsilateral station 4 via right-sided versus left-sided thoracotomy was 3.3 versus 2.5, respectively (p = 0.1). The number of dissected nodes from the contralateral station 2 via right-sided versus left-sided thoracotomy was 0.2 versus 2.1 (p = 0.000), whereas those numbers from the contralateral station 4 via right-sided versus left-sided thoracotomy were 1.0 versus 3.3, respectively (p = 0.000). Conclusions: Lymphadenectomy of the paratracheal area via left thoracotomy without ductus arteriosus division and mobilization of the aortic arch is technically feasible. From these data, regardless of approach, more lymph nodes are obtained from the right paratracheal space; this appears to be due to the fact that there are more right-sided paratracheal lymph nodes. (C) 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B. V. All rights reserved.