Blow-Out Fracture, Emergency Medicine

Basics

Description

Defined as an orbital floor fracture without orbital rim involvement
Results from sudden blunt trauma to the globe:
- Typically caused by the force of a projectile > half the size of the fist
Force transmitted through the noncompressible structures of the globe to the weakest structural point: The orbital floor
Transmitted force "blows out" or fractures the orbital floor.
Orbital floor serves as roof to air-filled maxillary and ethmoid sinuses:
- Communication between the spaces results in orbital emphysema.
Orbit contains fat, which holds the globe in place:
- Orbital floor fracture may result in herniation of the fat on the inferior orbital surface into the maxillary or ethmoid sinuses.
- Leads to enophthalmos owing to orbital volume loss and sinus congestion; fluid collection may occur secondary to edema and bleeding.
Infraorbital nerve runs through the bony canal 3 mm below the orbital floor:
- Injury may result in hypoesthesia of the ipsilateral cheek and upper lip.
- To distinguish facial hypoesthesia related to local swelling from nerve injury: Test for sensation on the ipsilateral gingiva, which is within the infraorbital nerve distribution.
Inferior rectus and the inferior oblique muscle run along the orbital floor:
- Restriction of these extraocular muscles may occur because of entrapment within the fracture, contusion, or cranial nerve dysfunction.
- Typically manifests as diplopia on upward gaze
- Inability to elevate the affected eye normally on exam
Medial rectus located above the ethmoid sinus:
- Less commonly entrapped
- Diplopia on ipsilateral lateral gaze

Etiology

Caused by a projectile which strikes the globe. The force is transmitted through the noncompressible structures of the globe to the weakest structural point: the orbital floor resulting in a blow out fracture.

Orbital roof fractures with associated CNS injuries more common in children
Orbital floor fractures: Unlikely before 7 yr of age:
- Orbital floor is not as weak a point in the orbit due to lack of pneumatization of the paranasal sinuses.
Unfortunately fractures can occur in children and may result in unrecognized entrapment of the rectus muscle labeled the "white-eyed" fracture:
- These children may present with marked nausea, vomiting, headache, and irritability suggestive of a head injury that commonly distracts from the true diagnosis.

Diagnosis

Signs and Symptoms

Periorbital tenderness, swelling, and ecchymosis
Impaired ocular mobility or diplopia:
- Restricted upward gaze owing to inferior rectus entrapment
- Restricted ipsilateral lateral gaze with medial rectus entrapment
Infraorbital hypoesthesia:
- Caused by compression/contusion of infraorbital nerve
- May extend to upper lip
Enophthalmos:
- Globe set back owing to orbital fat displaced through fracture
Periorbital emphysema:
- From the ethmoid or maxillary sinus
Epistaxis
Normal visual acuity:
- If not, consider more extensive injuries
No orbital rim step off

Associated Severe Injuries

Ocular injuries:
- Ruptured globe:
  - Incidence up to 30% of blow-out fractures
  - Ophthalmologic emergency
- Retrobulbar hemorrhage
- Emphysematous optic nerve compression
Cervical spine or intracranial injuries
Commonly associated injuries:
- Subconjunctival hemorrhage
- Corneal abrasion/laceration
- Hyphema
- Traumatic mydriasis
- Traumatic iridocyclitis (uveitis)
Less common:
- Iridodialysis
- Retinal detachment
- Vitreous hemorrhage
- Optic nerve injury
Associated fractures:
- Nasal bones
- Zygomatic arch fracture
- Le Fort fracture
Late complications:
- Sinusitis
- Orbital infection
- Permanent restriction of extraocular movement
- Enophthalmos

History
Struck in the eye with a projectile. Paintball, handball, racquetball, baseball, rock, or possibly fist. Larger-sized projectiles will likely be blocked by the orbital rim. Seen frequently after MVCs which are the most common cause of maxillofacial trauma.
Physical Exam

Thorough ophthalmologic exam:
- Palpate bony structures of the orbit for evidence of step off.
- Careful attention not to place pressure on the globe until ruptured globe excluded:
  - Desmarres lid retractors may be necessary to evaluate the eye with swollen lid.
Document pupillary response
Visual acuity (should not be affected):
- Handheld visual acuity Rosenbaum card is most useful with injuries.
Test extraocular movements for disconjugate gaze or diplopia.
Test sensation in inferior orbital nerve distribution.
Examine lid and adnexa:
- Orbital emphysema may be present.
Slit-lamp and fundoscopic exam to identify associated injuries.
Full physical exam to identify associated injuries and neurologic impairment.

Diagnosis Tests & Interpretation

Lab

Preoperative lab studies if indicated
Pregnancy testing prior to radiography

Imaging

If CT unavailable or contraindicated, plain radiographs will provide important information:
- Facial films
- Orbits
- Waters view and exaggerated Waters view:
  - Classic "teardrop sign" illustrates herniated mass of orbital contents in the ipsilateral maxillary sinus.
  - Opacification of or air-fluid level in the ipsilateral maxillary sinus (less specific)
  - Orbital floor bony fracture
  - Lucency in orbits consistent with orbital emphysema
CT-preferred modality:
- Defines involved anatomy
- Obtain axial and coronal 1.5-mm cuts:
  - Reconstruction of coronals not preferred but acceptable if positioning impossible

Diagnostic Procedures/Surgery
Forced duction test:

Distinguishes nerve dysfunction from entrapment
Topical anesthesia applied to the conjunctiva on the opposite side, and the globe is pulled away from the expected point of entrapment; if the globe is not mobile, the test is positive-defining physical entrapment.

Orbital CT: Study of choice:
- Plain films less helpful
Essential to identify entrapment early as long-term outcome will likely be affected if left undiagnosed:
- Early surgical intervention for entrapment may significantly improve outcome.

Differential Diagnosis

Cranial nerve palsy
Orbital cellulitis
Periorbital cellulitis
Periorbital contusion/ecchymosis
Retrobulbar hemorrhage
Ruptured globe

Treatment

Pre-Hospital

Metal protective eye shield if possible globe injury
Place in supine position.

Initial Stabilization/Therapy

Initial approach and immediate concerns:

Assess for associated intracranial or cervical spine injuries.
Rule out ruptured globe.
Test visual acuity:
- Decreased visual acuity suggestive of associated with more extensive injuries

Ed Treatment/Procedures

After globe rupture is excluded, apply cool compresses for the 1st 24-48 hr to decrease swelling to minimize or reverse herniation and avoid surgical intervention.
Avoid Valsalva maneuvers and nose blowing to prevent compressive orbital emphysema.
Prophylactic antibiotics to prevent infection
Nasal decongestants if no contraindication
Analgesics as needed
Tetanus prophylaxis

Medication

Antibiotics are recommended prophylactically to prevent sinusitis and orbital cellulitis:
- Cephalexin 250 mg q6h for 10 days
Systemic corticosteroids have been advocated to speed up the resorption of edema in order to more accurately assess any muscle entrapment and orbital damage:
- Prednisone (60-80 mg/d) within 48 hr of the injury and continued for 5 days
Nasal decongestants may be beneficial if not contraindicated:
- Phenylephrine nasal spray: BID for 2-4 days

Follow-Up

Disposition

Admission Criteria

Rarely indicated
85% resolve without surgical intervention.
Consultation with facial trauma service in ED and consideration for admission if:
- 50% of floor fractured
- Diplopia or entrapment is identified
- Particularly in children
- Enophthalmos >2 mm or more

Discharge Criteria
In most cases, observe for 10-14 days until swelling resolves, then follow up with facial trauma surgeon to determine need for surgical intervention.

Followup Recommendations

Symptoms should improve over time:

If at any point patient develops increased swelling, tenderness, redness, or pain around the eye, they should return to ED for re-evaluation.
If any visual disturbance, visual loss, or increased eye pain return to ED for re-evaluation.

Pearls and Pitfalls

Be hypervigilant in checking pupillary response and visual acuity:
- Abnormal results may be the 1st sign of serious complications:
  - Globe rupture
  - Optic nerve injury possibly stemming from emphysematous or retrobulbar compression
Careful evaluation for entrapment:
- Essential for all, but particularly children, to exclude white-eyed fracture and its long-term complications
The oculocardiac (Aschner) reflex may be associated with this injury. It manifests as a decrease in pulse rate associated with traction applied to extraocular muscles and/or compression of the eyeball:
- May be seen more commonly in children
- Treated by release of pressure and in some cases may require atropine

Additional Reading

Alinasab B, Ryott M, Stj ¤rne P. Still no reliable consensus in management of blow-out fracture. Injury. 2012;45:197-202.
Cruz AA, Eichenberger GC. Epidemiology and management of orbital fractures. Curr Opin Ophthalmol. 2004;15(5):416-421.
Gosau M, Sch ¶neich M, Draenert FG, et al. Retrospective analysis of orbital floor fractures - complications, outcomes and review of the literature. Clin Oral Investig. 2011;15(3):305-313.
Higashino T, Hirabayashi S, Eguchi T, et al. Straightforward factors for predicting the prognosis of blow-out fractures. J Craniofac Surg. 2011;22(4):1210-1214.

Codes

ICD9

376.52 Enophthalmos due to trauma or surgery
802.6 Closed fracture of orbital floor (blow-out)
802.7 Open fracture of orbital floor (blow-out)

ICD10

H05.429 Enophthalmos due to trauma or surgery, unspecified eye
S02.3XXA Fracture of orbital floor, init encntr for closed fracture
S02.3XXB Fracture of orbital floor, init encntr for open fracture

SNOMED

49346003 Closed fracture of orbital floor (blow-out)
3421000 Open fracture of orbital floor (blow-out)
52102006 Enophthalmos due to trauma

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