Introduction
Background
Orbital floor fractures may result when a blunt object, which is of equal or greater diameter than the orbital aperture, strikes the eye. The globe usually does not rupture, and the resultant force is transmitted throughout the orbit causing a fracture of the orbital floor. Signs and symptoms can be quite varied, ranging from asymptomatic with minimal bruising and swelling to diplopia, enophthalmos, hypo-ophthalmia (ie, hypoglobus), and hypoesthesia of the cheek and upper gum on the affected side. Treatment is titrated to the degree of injury.
Pathophysiology
The orbit and its contents are affected by orbital floor fractures. Direct fractures of the orbital floor can extend from orbital rim fractures, while indirect fractures of the orbital floor may not involve the orbital rim. The cause of the fracture is thought to be from increased intraorbital pressure, which causes the orbital bones to break at their weakest point. This is usually the medial orbital floor. Another theory is that compression of the inferior orbital rim causes direct buckling of the orbital floor. In either case, if the intraorbital pressure is great enough at the time of injury, orbital contents can be forced into the fracture site and possibly into the maxillary sinus.
Mortality/Morbidity
With simple blowout fractures, there may be no morbidity at all, or the patient may complain of diplopia, enophthalmos, or hypoesthesia of the cheek and gum. Edema and ecchymosis of the eyelids and periorbital region usually are seen but are temporary. With any injury that involves a sinus, air may escape into the orbit or subcutaneous tissues. This is called orbital emphysema.
- Vertical diplopia may be caused by entrapment of the perimuscular tissue surrounding the inferior rectus muscle in the fracture site. This results in limited upgaze and may cause pain on attempted upgaze as well. Damage to the third nerve branch to the inferior rectus muscle also may cause limited vertical motility. Severe pain with limited horizontal and vertical movements can be indicative of more severe orbital hemorrhage or edema.
- Enophthalmos may result when large orbital floor fractures occur and orbital contents prolapse into the maxillary sinus. If a medial wall fracture also has occurred, the enophthalmos may be compounded due to prolapse of orbital contents into the ethmoid sinus. Orbital edema that occurs at the time of injury initially may mask the enophthalmos, but the sunken eye appearance will become more apparent over the following 1-2 weeks as the edema subsides.
- Fractures along the floor usually affect the infraorbital groove and therefore the infraorbital nerve. The resultant neuropraxia causes hypoesthesia of the cheek and upper gum on the affected side. This is usually temporary but can last up to 6 months or longer. In severe injuries, the hypoesthesia may be permanent.
Sex
Because the usual mechanism of injury is assault with a blunt object, the vast majority of cases occur in males. In a study of facial fractures in an urban population, 81% of the patients were males.
Age
Because of the nature of the injury and its etiology (eg, assault), most orbital floor fractures occur in teenagers or young adults.
Clinical
History
- Patients may relay a history of the eye being struck by an object larger than the diameter of the orbital entrance. Fists, balls, or car dashboards are examples.
- Patients may have no complaints. However, they may complain of vision loss or diplopia. The double vision is often vertical and worse with attempted up or downgaze.
- Numbness (hypoesthesia) of the cheek and gum on the affected side may be present. Ecchymoses, ptosis (droopiness of the eyelid), and swelling around the eye may be noted.
- The examiner should obtain a past ocular history to assess whether any loss of vision or diplopia is due to the present accident or was established prior to this incident.
Physical
A complete ocular evaluation is essential to ensure that no injury to the globe or optic nerve has occurred.
- Visual acuity and pupils should be evaluated to ensure that no loss of vision or traumatic optic neuropathy has occurred.
- The examiner should evaluate extraocular movements and document any restriction or palsy.
- A complete slit lamp evaluation and measurement of intraocular pressures should be performed.
- Most posterior segment injuries can be ruled out with a dilated funduscopic examination.
- The physical findings may involve only periorbital edema and ecchymosis; however, more severe cases may demonstrate limited vertical movement, enophthalmos, ptosis, and possibly proptosis.
- Unusually severe orbital edema may be associated with more severe fractures and can cause proptosis. Once the edema has subsided (usually 1-2 wk), enophthalmos may be present.
- Limited vertical movement may be due to entrapment of the perimuscular fascia of the inferior rectus in the fracture site. However, traumatic palsy of the third nerve branch to the inferior rectus also may cause decreased extraocular movements. If a question exists, forced duction testing may differentiate between the two conditions.
- Hertel exophthalmometry may demonstrate either proptosis or enophthalmos and should be documented.
Causes
In a study of orbital fractures in an urban population, 70% of the fractures were due to assault with a blunt object (eg, fist, baseball bat), and 13% occurred due to a motor vehicle accident, usually involving striking the dashboard. Falls accounted for 10%, and gunshot wounds contributed to 6% of orbital floor fractures.
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References
Bansagi ZC, Meyer DR. Internal orbital fractures in the pediatric age group: characterization and management. Ophthalmology. May 2000;107(5):829-36. [Medline].
Della Rocca RC, Nassif JM. Blowout fractures. In: Linberg JV, ed. Oculoplastic and Orbital Emergencies. Appleton & Lange; 1990:155-165.
Egbert JE, May K, Kersten RC, et al. Pediatric orbital floor fracture : direct extraocular muscle involvement. Ophthalmology. Oct 2000;107(10):1875-9. [Medline].
Gilbard SM, Mafee MF, Lagouros PA, et al. Orbital blowout fractures. The prognostic significance of computed tomography. Ophthalmology. Nov 1985;92(11):1523-8. [Medline].
Green RP Jr, Peters DR, Shore JW, et al. Force necessary to fracture the orbital floor. Ophthal Plast Reconstr Surg. 1990;6(3):211-7. [Medline].
Jordan DR, Allen LH, White J, et al. Intervention within days for some orbital floor fractures: the white-eyed blowout. Ophthal Plast Reconstr Surg. Nov 1998;14(6):379-90. [Medline].
Kersten RC. Blowout fracture of the orbital floor with entrapment caused by isolated trauma to the orbital rim. Am J Ophthalmol. Feb 15 1987;103(2):215-20. [Medline].
Rubin PAD, Bilyk JR, Shore JW. Management of orbital trauma: fractures, hemorrhage, and traumatic optic neuropathy. Focal Points: Clinical Modules for Ophthalmologists. 1994;12:7.
Smith B, Regan WF. Blow-out fractures of the orbit: mechanism and correction of internal orbital fracture. Am J Ophthalmol. 1957;44:733.
Further Reading
Keywords
orbital floor fracture, orbital floor fractures, orbital fractures, orbital trauma, blowout fracture, floor fracture, facial trauma, facial fractures, blow-out fracture
