Orbital volumetric analysis of allergic fungal sinusitis patients with proptosis before and after endoscopic sinus surgery.

Background: The aim of this study was to examine the changes of orbital volumes in allergic fungal sinusitis (AFS) patients with proptosis who undergo endoscopic sinus surgery.

Methods: A retrospective study of operative patients with proptosis due to AFS was performed. Normative data were obtained using patients with chronic sinusitis without orbital involvement. Orbital volume measurements were obtained using digitized images and computer software to calculate volumes (cm3) of outlined regions on 1.3-mm axial computed tomography images. Orbital volumes were measured as total volumes and volumes within the bony orbit. Bony orbits were defined using two techniques: (1) the region posterior to a line from ipsilateral zygoma to contralateral zygoma and (2) the region posterior to a line from zygoma to ipsilateral lacrimal bone. Four affected orbits in three AFS patients with proptosis were evaluated. Twenty-eight unaffected orbits in 14 patients were used as normal comparisons.

Results: Orbital involvement by AFS resulting in proptosis decreased orbital volumes within the bony orbit to a mean of 70% of normal. After successful endoscopic sinus surgery, bony orbital volumes normalize or approach normal ranges to a mean 90% of normal with resolution of clinically apparent proptosis. Total volumes remained stable before and after surgery.

Conclusion: Massive AFS may affect the orbit resulting in proptosis. Spontaneous orbital remodeling with clinical resolution of proptosis and normalization of bony orbital volumes can be seen in AFS patients several months after sinus surgery and aggressive medical treatment. Surgical orbital reconstruction typically is not needed once the sinus disease is adequately addressed.