Blow-Out Fractures
Blow-out fractures are a type of orbital fracture involving the walls of the orbit, primarily the orbital floor. These fractures are commonly caused by blunt force trauma to the eye region.
Epidemiology and Aetiology:
Blow-out fractures account for approximately 5-24% of all facial fractures. Common causes include assaults, sports injuries, motor vehicle accidents, and falls. The primary mechanism of injury involves a direct blow to the eye, causing an increase in intraorbital pressure and subsequent fracture of the orbital floor.
Anatomy and Classification:
The orbit is composed of seven bones: frontal, maxillary, zygomatic, sphenoid, ethmoid, lacrimal, and palatine. Blow-out fractures typically involve the orbital floor, which is primarily formed by the maxilla and, to a lesser extent, the zygomatic and palatine bones. These fractures can be classified as:
Pure: Fracture of the orbital floor only, without involvement of the orbital rim
Impure: Fracture of the orbital floor along with an associated zygomaticomaxillary complex (ZMC) fracture or other facial fracture
Clinical Presentation:
Patients with blow-out fractures may present with the following signs and symptoms:
Periorbital swelling and ecchymosis
Subconjunctival haemorrhage
Restricted eye movement, particularly in upward gaze (due to entrapment of the inferior rectus muscle)
Enophthalmos (posterior displacement of the eyeball)
Diplopia (double vision)
Numbness or paresthesia in the distribution of the infraorbital nerve (lower eyelid, cheek, upper lip)
Diagnostic Approach:
The diagnostic workup of a patient with a suspected blow-out fracture should include:
History: Obtain a detailed history of the mechanism of injury and assess for potential risk factors.
Physical Examination: Inspect for periorbital swelling, ecchymosis, and subconjunctival haemorrhage. Assess ocular motility, visual acuity, pupillary response, and fundoscopy. Palpate the orbital rim and facial bones for tenderness or deformity. Examine the patient for other injuries or signs of trauma.
Imaging: Obtain a non-contrast facial CT scan with coronal and axial views. This is the gold standard for diagnosing orbital fractures and assessing the degree of displacement, muscle entrapment, and orbital soft tissue involvement.
Treatment:
The goals of treatment for blow-out fractures are to restore normal orbital function, ocular motility, and facial aesthetics. Treatment options depend on the type, severity, and complications of the fracture, as well as patient factors. They include:
Conservative Management: Indicated for minimally displaced fractures without significant ocular symptoms. This involves analgesics, oral antibiotics, nasal decongestants, and close follow-up.
Surgical Intervention: Indicated for fractures with significant displacement, muscle entrapment, enophthalmos, or persistent diplopia. This involves open reduction and internal fixation (ORIF) using various materials such as titanium plates, resorbable plates, or porous polyethylene implants.
Post-operative Care: Includes pain management, antibiotics, wound care, and regular follow-up.
