Orbital Floor Fracture With Haller Cells and Inferior Rectus Injury Post-Endoscopic Sinus Surgery.

A 27-year-old male developed diplopia and gaze limitation after endoscopic sinus surgery (ESS) due to an iatrogenic inferior rectus (IR) muscle injury caused by an orbital floor fracture involving Haller cells. Preoperative CT and MRI confirmed this injury. Intraoperatively, a fracture and soft tissue herniation were found and their reduction improved upward extraocular movement (EOM), although downward EOM remained limited. Although initial postoperative improvement was observed, at the 1-year follow-up, the patient showed overall recovery compared with the initial injury but declined from the immediate postoperative state, likely due to muscle injury-induced paralysis. Hence, facial bone surgeons should consider both orbital wall fractures and rectus muscle injuries when a patient presents with diplopia after ESS. Preoperative imaging, such as CT or MRI, is essential. IR muscle injury can lead to IR palsy, potentially resulting in an initially improved postoperative condition but a less favorable long-term prognosis.