A 42-year-old man was involved in a motor vehicle collision. Imaging studies revealed the presence of a post-traumatic aortic pseudo-aneurysm (about 34 × 26 cm) arising from the descending thoracic aorta at the level of the left subclavian artery (LSA), prone to rupture. Thoracic endovascular aneurysm repair (TEVAR) was the only feasible option due to his poor overall medical status. In this case, LSA needed to be covered in order to extend the proximal landing zone. Eventually, modified TEVAR was successfully performed by means of the chimney technique to preserve flow to the LSA and to prevent flow into the pseudoaneurysmal sac.