Sudden Diplopia Two Months After a Blowout Fracture: A Case Report of Orbital Tissue Adhesion Associated With Acute Sinusitis.

Blowout fractures (BOFs) frequently result in early-onset diplopia, which often resolves spontaneously. Delayed diplopia is rare, and there are no reported cases of its sudden onset following a prolonged asymptomatic period. Persistent diplopia significantly impacts quality of life. BOF-induced late-onset diplopia is rare. To date, no cases of late-onset or acute-onset diplopia have been reported, underscoring its exceptional rarity. This report discusses a unique case of sudden diplopia two months post BOF, which improved after surgical treatment. A 57-year-old man presented with a history of BOF without initial diplopia. Two months post injury, he developed acute diplopia on an upward gaze. Computed tomography revealed an extensive orbital floor fracture with herniation into the maxillary sinus and odontogenic maxillary sinusitis. The late-onset diplopia was believed to be caused by adhesions of the tissues surrounding the inferior rectus muscle due to the spread of maxillary sinus inflammation into the orbit. Surgery was performed 154 days after the trauma, which included endoscopic sinus surgery and transconjunctival orbital floor repair. Intraoperatively, the maxillary sinus mucosa was severely edematous and prone to bleeding. Adhesions between the tissue around the inferior rectus muscle and orbital floor were identified and sharply dissected. Surgical intervention effectively resolved enophthalmos and significantly improved diplopia. This case of BOF is extremely rare, as diplopia developed both late and suddenly. Although 154 days had passed since the trauma, the patient showed significant improvement following surgical treatment. The cause of the late and acute-onset diplopia is believed to be the spread of inflammation from odontogenic maxillary sinusitis into the orbit, resulting in adhesions in the tissues surrounding the inferior rectus muscle. Delayed onset of diplopia in BOF may be an early symptom of intraorbital inflammation. In cases of extensive BOF accompanied by paranasal sinusitis with severe inflammation, we believe that several months of follow-up observation is necessary to prevent late complications.