Silent sinus syndrome (SSS) or chronic maxillary atelectasis (CMA) is characterized by enophthalmos or hypo Globus along with maxillary sinus atelectasis and lateralization of the uncinate process without classic rhino sinusitis symptoms. A previous description of surgical management includes maxillary antrostomy with orbital floor repair via an implant, possibly as a two-stage procedure. The objective of this study was to evaluate single-stage endoscopic correction of SSS/CMA via endoscopic maxillary mega-antrostomy without performing planned up-front orbital correction. Eight patients (9 sinuses) in our retrospective review underwent single-stage endoscopic maxillary mega-antrostomy as first-line treatment with removal of the middle 1/3 of the inferior turbinate and medial maxillary wall due to the inferior location of the orbital floor and lateralized uncinate compared to the natural ostium. There were no complications. All sinuses remained ventilated in our study at a mean follow up of 10.3 months without the need for corrective orbital surgery. This method is a reasonable sinus ventilation and resolution of hypoglobus or enophthalmos (if present) while still safely opening the sinus.