Silent sinus syndrome

Findings

Two coronal CT images (Figure 1 and Figure 2) and single axial CT image (Figure 3 ) demonstrate right maxillary sinus volume loss when compared to the left. There is inward retraction of the sinus walls (Figure 1, Figure 2, and Figure 3), increase in the size of the middle meatus (Figure 1 and Figure 2) and expansion of the retroantral fat (Figure 3). There is lateralization of the uncinate process and middle turbinate. This patient had concomitant right ethmoid air cell and frontal sinus opacification.


Diagnosis: Silent sinus syndrome


Silent sinus syndrome, or maxillary sinus atelectasis, is characterized by volume loss of the maxillary sinus after infundibular occlusion. It most often presents in the third through fifth decades of life with painless enophthalmos, facial asymmetry, and/or diplopia. Rarely do patients complain of symptoms of sinusitis.

Imaging findings of silent sinus syndrome are characteristic. There is maxillary sinus volume loss with inward retraction of the sinus walls and sinus opacification. The ethmoidal infundibulum is occluded, usually due to opposition of the uncinate process against the inferomedial orbit. The sinus volume loss accounts for the corresponding increase in ipsilateral orbital volume and size of the middle meatus.

The pathophysiology remains unclear. It is felt to be an acquired condition caused by chronic maxillary sinus obstruction and hypoventilation leading to negative intrasinus pressures. Chronic inflammation leads to osteolysis and thinning of the sinus walls which are retracted by the negative sinus pressure.

Treatment is aimed at creating an outlet for obstructed mucous via a nasal antral window or maxillary antrostomy. The goal of surgery is to prevent disease progression and further deformity.