Blow-out fracture of orbit: Description, Causes and Risk Factors:
Blowout fractures are caused by direct trauma to the globe which causes an increase in intraorbital pressure and decompression via fracture of the orbital floor.
When the blow-out fracture occurs as a result of a direct injury, it is usually in conjunction with a naso-orbital fracture, which results from direct application of blunt force to the naso-orbital area. The most frequent cause of these naso-orbital fractures is a motor vehicle accident (MVA) that results in the face impacting against the steering wheel or dashboard; additional causes include blunt trauma from the fist or the elbow. Medial wall blow-out fractures are potential sequelae of blunt periorbital trauma. Common causes for this type of medial wall fracture include fists, elbows, shoe kicks, baseballs, and tennis balls, all of which have a diameter greater than the orbital rim.
A naso-orbital fracture tends to consist of a comminuted, depressed fracture involving the nasal bones, ethmoid sinuses, and medial orbital walls. It occurs when a blow of sufficient force is applied to the nasal bridge area. Such blunt trauma can cause the medial wall to develop a fracture in 1 of 2 ways. First, when the nasal bone
fragments are projected backward, the thin lacrimal bone and lamina papyracea are comminuted easily. The nasal bone and frontal process of the maxilla may be displaced posteriorly into the ethmoid sinus; as a result, an in fracturing of the medial orbital wall into the orbit occurs. Therefore, the compressive force causing nasal fractures is a very important causative factor of pure medial wall fractures.
With blow-out fractures, the medial wall is fractured indirectly. When an external force is applied to the orbital cavity from an object whose diameter is larger than that of the orbit, the orbital contents are retropulsed and compressed. The consequent sudden rise in intraorbital pressure is transmitted to the walls of the orbit, which ultimately leads to blow-out fracture of the thin medial wall and/or orbital floor. Theoretically, this mechanism should lead to more fractures of the medial wall than the floor, since the medial wall is slightly thinner (0.25 mm vs 0.50 mm). However, it is known that pure blow-out fractures most frequently involve the orbital floor. This may be attributed to the honeycomb structure of the numerous bony septa of the ethmoid sinuses, which support the lamina papyracea, thus allowing it to withstand the sudden rise in intraorbital hydraulic pressure better than the orbital floor.
Approximately 2.5 million traumatic eye
injuries, including eye socket fractures, occur each year in the US. About 85% of these injuries happen by accident, during contact sports, at work, in car crashes or while doing home repair projects. About 15% are caused by violent assaults. Men suffer from traumatic eye injuries about four times more often than women do. The average age of the injured person is about 30. The source of the injury is usually a blunt object -- baseball, hammer, rock, piece of lumber -- and the most frequent place of injury is the home. At one time, eye injuries were common in motor vehicle accidents, usually when a victim's face struck the dashboard. Such eye injuries have decreased dramatically because more cars have airbags, and most states have laws mandating the use of seat belts.
Symptoms vary, depending on the location and severity of the blow-out fracture, but can include:
Double vision, decreased vision or blurry vision.
Diagnosis of blow-out fracture:
- Difficulty looking up, down, right or left.
- A black eye, with swelling and black and blue discoloration around the injured eye; possible redness and areas of bleeding on the white of the eye and on the inner lining of the eyelids.
- Abnormal position of the eye (either bulging out of its socket or sunken in).
- Numbness in the forehead, eyelids, cheek, upper lip or upper teeth on the same side as the injured eye, possibly related to nerve damage caused by the fracture.
- A puffy accumulation of air under the skin near the eye, usually a sign that the fracture has broken through the wall of a sinus cavity, particularly the maxillary sinus, an air-filled chamber located inside the cheek below the eye.
- Swelling and deformity of the cheek or forehead, with an obvious dent over the area of broken bone.
- An abnormally flat-looking cheek, and possibly severe pain in the cheek when you attempt to open your mouth.
If you are conscious and able to answer questions after your injury, your doctor will review your symptoms and ask how your eye injury occurred. He or she will examine your eye, and will gently touch and press on your cheek and forehead to check if these areas are distorted. The doctor also will check for:
Whether you can look upward, downward or sideways -- If your doctor suspects that one of your eye muscles has become trapped in the fracture site, he or she may grasp the tendon of your eye muscle and attempt to rotate the eye by hand.
- Changes in vision, especially double vision.
- Areas of numbness in your forehead, eyelids, cheek, upper lip and upper teeth.
- Internal damage -- Your doctor will look inside your eye with an instrument called an ophthalmoscope to check for signs of internal damage. If the examination suggests you have an eye socket fracture, the doctor will confirm the diagnosis with X-rays or a computed tomography (CT) scan of the area around your eye.
In someone who is unconscious and has severe facial injuries, doctors can confirm the diagnosis of an eye socket fracture with X-rays and a CT scan of the eye socket bones. This is done after any life-threatening injuries have been addressed and the person's condition has stabilized.
Treatment of blow-out fracture:
Medical treatment is warranted for patients for whom surgery is not indicated. This may include patients who present without significant enophthalmos (2 mm or more), a lack of marked hypo-ophthalmus, absence of an entrapped muscle or tissue, a fracture less than 50% of the floor, or a lack of diplopia.
The patient can be treated with oral antibiotics on an empiric basis due to the disruption of the integrity of the orbit in communication with the maxillary sinus.
A short course of oral prednisone reduces edema of the orbit and muscle, allowing for a better assessment of enophthalmos or entrapment.
Discourage nose blowing to avoid creating or worsening orbital emphysema. Nasal decongestants can be used if not contraindicated.
Surgical repair is performed if the diplopia is unlikely to resolve spontaneously, there is severe enophthalmus, or the fracture is so large that the development of enophthalmus is likely.
Surgical repair of a "blowout" is rarely undertaken immediately; it can be safely postponed for up to two weeks, if necessary, to let the swelling subside. Surgery to place an orbital implant leaves little or no scarring and the recovery period is usually brief. Hopefully, the surgery will provide a permanent cure, but sometimes it provides only partial relief from double vision or a sunken eye.
Almost all blow-out fracture can be prevented. To decrease your risk of fracturing your eye socket:
Use appropriate protective eyewear while working. Studies have shown that face shields, goggles and other protective eyewear can reduce the risk of work-related eye injuries by more than 90%.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.
- Ask an experienced ophthalmologist, optometrist or optician for help in selecting appropriate protective eyewear for your sport. Baseball and basketball cause the greatest number of eye injuries.
- Do not allow your child to participate in amateur boxing. The American Academy of Pediatrics opposes the sport of boxing for young people.
- Always use a seat belt when you ride in a car, even if your car is equipped with airbags. Seat belts and shoulder harnesses will help to protect your eyes, facial bones and upper body from dashboard impacts and other injuries.