OBJECTIVE: Bilateral lung volume reduction surgery (LVRS) has emerged as a palliative treatment option in patients with severe pulmonary emphysema. However, it is not known if a sustained functional improvement can be obtained using an unilateral approach. METHODS: We hypothesized that a palliative effect can also be obtained by unilateral LVRS and prospectively assessed lung function, walking distance, and dyspnea before and 3, 6, 12, 18, 24 and 36 months after unilateral LVRS. RESULTS: Twenty-eight patients were operated by the use of video-assisted thoracoscopic surgery (VATS) with a mean follow-up of 16.5 months (range 3-36 months). Forced expiratory volume in 1 s (FEV1) was significantly improved up to 3 months (1007+/-432 compared to 1184+/-499 ml, P<0.001), residual volume up to 24 months (4154+/-1126 compared to 3390+/-914 ml, P<0.01), dyspnea up to 12 months (modified Borg dyspnea scale 6.6+/-1.8 compared to 3.9+/-1.8, P=0.01) and walking distance up to 24 months (343+/-107 compared to 467+/-77 m, P<0.05) after unilateral LVRS compared to preoperative values. Overall, 25 of 28 patients reported a subjective benefit after unilateral LVRS. There was no 30-day mortality. Only two patients required surgery on the contralateral side after 4.5 and 6 months, respectively, both suffering from alpha-1-antitrypsin deficiency. CONCLUSIONS: Unilateral LVRS by the use of VATS results in a sustained beneficial effect, improving walking distance and dyspnea for up to 24 months in patients with severe emphysema. The preservation of the contralateral side for future intervention if required renders unilateral LVRS an attractive concept in this difficult palliative situation.