Objective: To explore an innovative approach for left subclavian artery (LSA) reconstruction during thoracic endovascular repair. Methods: In two cases of thoracic endovascular repair requiring LSA reconstruction via fenestration in situ, a commercially available device and equipment were employed. Results: All cases achieved technical success without endoleak or stent graft migration. Conclusion: Fenestration in situ is an effective method for endovascular LSA reconstruction. However, the long term clinical outcome awaits further follow-up.