Strabismic complications following endoscopic sinus surgery: diagnosis and surgical management.

INTRODUCTION Endoscopic surgical techniques improve the surgeon's view of sinus structures but are subject to extraocular muscle complications that cause permanent diplopia. METHODS A series of 15 patients with strabismus following endoscopic sinus surgery was reviewed retrospectively to characterize the type of muscle injury and report the results of surgical correction. RESULTS A variety of insults to the medial rectus (MR) muscle occurred, ranging from contusion, hematoma, oculomotor nerve damage with paralysis, muscle transection, and muscle destruction. Inferior rectus and superior oblique muscle trauma was observed. High-resolution computed tomography and magnetic resonance imaging scans proved essential in determining the extent and nature of muscle injury. Surgical approaches included anterior orbitotomy with muscle recovery and transposition procedures. CONCLUSIONS Several extraocular muscles may be traumatized. Timing and type of surgical treatment depend on severity, type of injury, and number of muscles involved. If the remaining posterior segment of the MR muscle is longer than 20 mm and is contractile, muscle recovery via anterior orbital approach is suggested. If injury is more severe, muscle transposition procedures may be helpful. In cases where there is coexistent medial and inferior rectus injury, transposition procedures may not be possible. Inactivation of the antagonist and use of an orbital periosteal flap as a globe tether to center it may be options.