Superior oblique and inferior rectus muscle injury following frontal and intranasal sinus surgery.

Chronic inflammatory sinus disease is a common process, sometimes requiring nasal and paranasal sinus surgery. Extraocular muscle dysfunction is a rare surgical complication of sinus surgery, but has been reported. Previous studies have been concerned with trauma to the medial rectus muscle resulting in severe paralysis or restriction. This study reports five patients with acquired strabismus and symptomatic vertical diplopia secondary to sinus surgery. In all patients, the resultant diplopia was disabling. Four patients had frontal sinus window surgery performed, with incisions placed in the supero-nasal quadrant of the orbit, below the eyebrow (a modified Lynch incision). Three patients acquired a superior oblique paresis and the fourth developed a Brown's syndrome. The location of the skin incision was critical to injury in the trochlear area. The fifth patient underwent a nasal polypectomy and antrostomy with secondary orbital hemorrhage and proptosis. A mild inferior rectus paresis was the result.