Orbital complications of functional endoscopic sinus surgery: MR and CT findings.

Aim: To describe the radiological findings of ophthalmic complications during functional endoscopic sinus surgery (FESS) and correlate them with the clinical manifestations and mechanisms of injury.
Methods: This was a retrospective review of the clinical and cross-sectional imaging findings of 9 patients with orbital complications during FESS.
Results: The most common site of entry into the orbit during FESS was the lower medial orbital wall (7 of 9), followed by the inferior orbital wall, resulting in injury to the medial rectus (4 of 9) and, less frequently, the inferior rectus (2 of 9) or superior oblique muscles (1 of 9). Extensive scarring on imaging (3 of 9) was associated with global ocular motility dysfunction. In contrast, localized scarring (3 of 9) or extraocular muscle trauma (6 of 9) resulted in disturbance of eye movement in the direction of gaze from the injured site.
Conclusions: Orbital magnetic resonance and computed tomography findings correlate very well with the abnormal eye movements clinically observed, and can assist in clarifying the cause of injury and guide surgical corrective management of patients suffering orbital complications from FESS. Radiologists should be familiar with the recent developments in FESS instrumentation as well as with the most commonly injured structures within the orbit.