Navigating the Rare Medial Rectus Entrapment in Orbital Fractures: A 5-Year Series and Systematic Review of the Literature

Abstract

Background: Inferior rectus muscle entrapment associated with orbital floor fractures is commonly described in the literature. Less commonly described, however, is the phenomenon of medial rectus entrapment found in association with medial orbital wall fractures. This study primarily aims to bring further attention to this rare occurrence through the presentation of three medial rectus entrapments encountered at a single institution. Additionally presented are a systematic review of the literature and a discussion of the authors' preferred surgical technique for management of acute medial rectus entrapment in the setting of medial orbital wall fractures.

Methods: A systematic review of the literature was conducted via use of Medline/PubMed databases, and publications describing cases of medial rectus entrapment secondary to medial orbital wall fractures were included. Key data points included laterality of fracture, time to operative intervention, surgical approach, and outcomes pertaining to extraocular muscle motility. These results were pooled with the findings of our three-patient case series to report the postoperative rate of extraocular movement deficit/diplopia.

Results: Each patient in our series presented with inability to abduct the affected eye, diplopia with straight gaze, and a positive oculocardiac reflex. All three were managed emergently in the operating room with medial rectus release and repair of fracture with an alloplastic implant via a retrocaruncular approach with retroseptal floor extension. Diplopia resolved completely in two of the cases and remained at extremes of gaze at 1 month postoperatively for the third, at which time the patient was lost to follow-up. These results were pooled with those obtained from the literature resulting in a 62.1% rate of full recovery with 37.9% of patients experiencing some degree of diplopia at longest follow-up reported (which was limited in several cases).

Conclusions: This study serves to bring awareness to the phenomenon of medial rectus entrapment, so clinicians may keep an appropriate level of suspicion when evaluating patients with orbital fractures, as well as counsel patients appropriately regarding the long-term sequelae of this condition. Additionally, we have found that the retrocaruncular approach for surgical management of these fractures is safe and reliable, even in instances of significant chemosis and periorbital edema.

Keywords: entrapment; medial rectus; orbital fracture; retrocaruncular approach.