A child presents with enophthalmos, limited upgaze, and diplopia following blunt orbital trauma. CT orbit shows a trapdoor fracture of the orbital floor with a soft tissue density in the maxillary sinus and a small bone defect. The urgency for surgical repair is based on which finding?

• A Enophthalmos greater than 2 mm
• B Entrapment of the inferior rectus muscle with oculocardiac reflex (bradycardia, nausea, syncope) ✓
• C Diplopia persisting beyond 1 week
• D Maxillary sinus clouding on CT

Explanation

In pediatric trapdoor orbital floor fractures, the elastic bone creates a trap-door mechanism that entraps the inferior rectus or its connective tissue septa. Entrapment with oculocardiac reflex (bradycardia, nausea, vomiting, syncope from stretched vagal afferents) is an ocular emergency requiring surgical exploration within 24–48 hours to prevent ischemic muscle necrosis and permanent motility restriction. In adults, surgical repair can be deferred 1–2 weeks; in children with trapdoor fractures, urgency is driven by the oculocardiac reflex and muscle ischemia risk.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.