Background: The first case report of spontaneous enophthalmos due to maxillary atelectasis as a late complication of FESS is presented.
Methods: Chart review of a 24-year-old male who developed a left progressive enophthalmos within three months post bilateral functional endoscopic sinus surgery.
Results: The preoperative computed tomography showed a normal left maxillary sinus. The postoperative computed tomography revealed a left maxillary atelectasis with a descending orbital floor. The subject received revised endoscopic sinus surgery and his enophthalmos was stable without further progression after the operation.
Conclusions: This may have been caused by an ostium occlusion with retention of secretions inducing sinus inflammation, osteolytic activity, and osseous remodeling of the sinus walls. A negative pressure may develop. When the pressure gradient exceeds the sinus wall tension, maxillary atelectasis and enophthalmos occur. Prevention of this complication of FESS should include making a patent naso-antral window, minimizing mucosal trauma, and careful postoperative sinoscopic treatment. A "functional" sinus is the goal.