CT characterization of developmental variations of the paranasal sinuses in cystic fibrosis

To describe variations of paranasal sinus development in patients with cystic fibrosis (CF) and in non-CF patients examined for inflammatory sinonasal disease. We focused on anatomic variants that predispose to orbital and cerebral penetration during functional endoscopic sinus surgery (FESS), e.g. hypoplasia of the maxillary sinus and low ethmoid roof.

One hundred and sixteen CF patients (3-54 years, median 18) and 136 control patients (7-51 years, median 31) were examined with coronal CT of the paranasal sinuses. CF patients were grouped according to number of confirmed mutations: CF-2 (n=70), CF-1 (n=32), CF-0 (n=14). CT images were evaluated with respect to paranasal sinus development, pneumatization variants and bony variants.

Frontal sinus aplasia and maxillary, ethmoid, and sphenoid sinus hypoplasia were markedly more frequent in CF-2 than in control patients. No CF-2 patient had pneumatization variants such as Haller cells or concha bullosa. Low ethmoid roof was seen in 30% of CF-2 children, but in no control children. CF-1 and CF-0 groups had prevalences of aplasia and hypoplasia intermediate to that of CF-2 and control patients.

Genetically verified CF patients had less developed sinuses, lacked pneumatization variants, and more often had anatomic variants that predispose to complications during FESS. Normally developed sinuses and pneumatization variants in some genetically unverified CF patients (CF-1, CF-0) suggest that these patients may be erroneously diagnosed.