Dynamic change in silent sinus syndrome

A 32-year-old male patient presented to the otolaryngology outpatient department after experiencing visible progressive facial misalignment for 3 weeks. He complained about the sunken appearance of his left eye and the asymmetric protrusion of his bilateral maxillary bone. However, he had no history of recent facial trauma, sinus surgery, or any nasal or ophthalmological symptoms. Physical examination revealed a deepening of the left superior orbital sulcus and left hypoglobus (Figure 1A). The patient's visual acuity and extraocular movements were normal. Nasal endoscopy indicated the absence of polyps, purulent secretion, edematous mucosa, or any other abnormality. Subsequent computed tomography (CT) revealed that all the walls of the left maxillary sinus were bowing inward, causing a considerable reduction in the sinus volume and a downward displacement of the orbital floor (Figure 1B,C). A diagnosis of silent sinus syndrome (SSS) was made. During endoscopic maxillary antrostomy performed under general anesthesia, total occlusion of the maxillary sinus ostium and the accumulation of mucus were discovered. Patency of the maxillary sinus was subsequently achieved.

FIGURE 1. Clinical images show (A) posterior and inferior displacement of the eye. (B) Axial computed tomography (CT) reveals inward bowing of anterior, medial, and posterior lateral walls of left maxillary sinus (arrows). (C) Coronal CT indicates downward displacement of orbital floor (arrows). At 6 months postsurgery, (D) follow up reveals improvement in downward position of affected eye (E,F), and follow-up CT reveals improved maxillary sinus bowing and downward placement of left orbital floor (arrows).

Six months after the maxillary antrostomy, the patient self-reported improved facial asymmetry (Figure 1D), and a follow-up CT scan revealed a substantial expansion of the size of the patient's maxillary sinus and an improvement in his enophthalmos (Figure 1E,F).

The criteria for diagnosing SSS include spontaneous enophthalmos and/or hypoglobus, contraction of the maxillary sinus with osteomeatal complex (OMC) occlusion on CT images as well as the absence of symptoms of sinonasal inflammatory disease, orbital trauma, or any congenital deformity.^1–3 The pathophysiology of SSS involves maxillary sinus hypoventilation after total OMC occlusion. Subsequent gas resorption leads to sub-atmospheric pressure, creating a vacuum that causes sinus wall retraction. Over time, the maxilla bone undergoes secondary demineralization, and the resulting negative sinus pressure causes the weakened areas to implode.⁴ This phenomenon was confirmed by Kass et al.⁵ a series of human studies.

When SSS was first described in 1990s, the Caldwell-Luc procedure was the conventional surgical solution. However, the treatment trend has shifted to endoscopic surgery, which provides advantages such as reduced infection rates, a reduced risk of numbness, and improved maxillary sinus aeration. Nevertheless, the endoscopic procedure must be performed carefully to prevent orbital content from prolapsing into the maxillary sinus.

A major debate is whether orbital floor reconstruction should be performed during maxillary surgery. Some surgeons prefer a one-stage approach, whereas others recommend a watch-and-wait strategy because spontaneous re-expansion and atelectasis resolution can occur to some extent after the maxillary ostium is widened.^2–4

Our patient only underwent maxillary surgery, and at 6 months after the procedure, we observed the regression of enophthalmos and an increase in the maxillary sinus size. This result suggests that simultaneous endoscopic antrostomy and orbital floor reconstruction are not required.

In summary, this report presents a rare clinical case of a patient who visited our institution solely because of aesthetic concerns. Furthermore, the patient was pleased with the cosmetic results achieved through accurate diagnosis and treatment.

CONFLICT OF INTEREST STATEMENT

All authors declare no conflict of interest.

ETHICS STATEMENT

Approval for retrospective data collection/secondary use of health information was obtained from the Institutional Review Board of Kaohsiung Medical University Hospital (KMUHIRB-E(I)-20230135).