Management of a Comminuted Zygomaticomaxillary Complex Fracture with Ocular Involvement
A 28-year-old man presents to the emergency department after a motor vehicle collision. He has a comminuted fracture of the left zygomaticomaxillary complex (ZMC) with displacement. He complains of double vision, especially when looking up, and has numbness in the left cheek. On examination, he has a 4 mm left enophthalmos, a positive forced duction test on the left, and decreased sensation in the distribution of the left infraorbital nerve. His visual acuity is 20/20 in both eyes. CT scan shows a comminuted fracture involving the zygomatic arch, lateral orbital wall, orbital floor, and anterior maxilla. There is a fracture of the orbital floor with herniation of orbital fat into the maxillary sinus. The patient is otherwise healthy and has no other injuries. The plastic surgery team is consulted.
1. What is the significance of the positive forced duction test and the enophthalmos? How do these findings influence your management?
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A positive forced duction test indicates mechanical restriction of extraocular muscle movement, likely due to entrapment of the inferior rectus or periorbital tissue in the orbital floor fracture. This is a sign of muscle incarceration, which can lead to ischemia and fibrosis if not addressed promptly. The enophthalmos of 4 mm suggests an increase in orbital volume due to the floor fracture and fat herniation, which can cause cosmetic deformity and functional issues. Together, these findings indicate a high risk of persistent diplopia and cosmetic deformity if not treated.
The management should be urgent surgical exploration and repair of the orbital floor to release the entrapped tissue and restore orbital volume. The comminuted ZMC fracture also requires stabilization. The approach should be multidisciplinary with ophthalmology. The timing of surgery: within 24-48 hours if there is evidence of muscle entrapment with nausea, vomiting, or bradycardia (oculocardiac reflex), but in this case, the patient has diplopia and positive forced duction without systemic symptoms, so surgery can be performed within a few days. However, early intervention is preferred to prevent fibrosis. The surgical approach may include a subciliary or transconjunctival incision with lateral canthotomy for orbital floor access, and a coronal or preauricular approach for the zygomatic arch. Fixation with plates and screws, and reconstruction of the floor with a titanium mesh or porous polyethylene implant. The infraorbital nerve should be decompressed if compressed.
2. What are the potential complications of this injury and its surgical treatment, and how can they be prevented or managed?
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Complications include:
Persistent diplopia: due to muscle entrapment, scarring, or malposition of the globe. Prevention: accurate anatomical reduction and release of entrapment. Management: if persists after 6 months, may require strabismus surgery.
Enophthalmos: due to inadequate restoration of orbital volume. Prevention: overcorrection of the floor with implant, and proper fixation of the zygoma. Management: revision surgery with orbital floor implant or fat grafting.
Infraorbital nerve injury: may be transient or permanent. Prevention: careful dissection and decompression of the nerve. Management: observation, medications for neuropathic pain.
Orbital compartment syndrome: rare but vision-threatening. Prevention: careful hemostasis, avoid tight closure, monitor postoperative vision. Management: emergent canthotomy and cantholysis.
Implant complications: infection, extrusion, migration. Prevention: proper implant selection and fixation, antibiotic prophylaxis. Management: removal and replacement.
Malunion: due to inadequate reduction. Prevention: proper exposure and fixation. Management: osteotomy and re-fixation.
Scarring: cosmetic. Prevention: meticulous closure.
Sinusitis: due to obstruction of the ostium. Prevention: avoid implant blocking the ostium.
Blindness: rare, due to optic nerve injury or retrobulbar hemorrhage. Prevention: careful dissection, hemostasis, and monitoring.
Infection: prophylaxis with antibiotics.
Postoperative monitoring includes visual acuity checks, pain assessment, and imaging if needed.