Extraocular Muscle Injury in Zygomatic Implant Placement: A Case Report, Review of the Literature, and Simple Maneuver for Avoidance

Abstract

Zygomatic implants (ZIs) are used to support dental prostheses in patients with inadequate maxillary bone volume. Although the ZI success rates have been high, cases of inadvertent orbital entry during zygoma drilling have been reported, with varying severity of clinical sequelae. We report the second case treated at our institution of inadvertent orbital entry during zygoma drilling. The patient experienced partial lateral rectus muscle transection resulting in diplopia, and ultimately underwent strabismus surgery. Postoperatively, his diplopia resolved, and only a small angle esophoria persisted. A review of the literature revealed 3 other cases of extraocular muscle injury secondary to orbital entry during zygoma drilling, all of which required strabismus surgery to restore alignment. We propose placement of a metal shoehorn in the inferior fornix during zygoma drilling to protect the globe and intraorbital structures from injury in the event of orbital entry.