Silent sinus syndrome.

Background: Silent sinus syndrome (SSS) is similar to and a subset of chronic maxillary atelectasis (CMA), which refers to a persistent decrease in sinus maxillary volume due to inward retraction of the maxillary sinus walls secondary to obstruction of the osteomeatal complex. It differs from CMA, however, in that there is no pain or maxillary sinus congestion. Patients with SSS usually manifest spontaneous unilateral enophthalmos and hypoglobus, with no history of facial trauma or surgery.