Orbital fractures

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"Explosive" fracture of the orbital floor

A "pure" orbital fracture does not involve the orbital rim, whereas a "mixed" fracture involves the orbital rim and adjacent facial bones. A "blowout" orbital floor fracture is usually caused by a sudden increase in intraorbital pressure from an impact with an object larger than 5 cm in diameter, such as a fist or tennis ball. Because the lateral wall and roof of the orbit can usually withstand such an impact, the fracture most often involves the orbital floor along with the thin bones that form the walls of the infraorbital fissure. In some cases, the medial orbital wall is also fractured. Clinical manifestations vary depending on the severity of the injury and the time interval between injury and examination.

Symptoms of a blast fracture of the orbital floor

1. Periocular signs: chemosis, edema and subcutaneous emphysema of varying degrees.
2. Anesthesia of the distribution area of the infraorbital nerve affects the lower eyelid, cheek, bridge of the nose, upper eyelid, upper teeth and gums, since a “blowout” fracture often affects the walls of the infraorbital fissure.
3. Diplopia may be caused by one of the following mechanisms:
   • Hemorrhage and edema cause compaction of the orbital tissue between the inferior rectus, inferior oblique muscles, and periosteum, which limits the mobility of the eyeball. Ocular mobility usually improves after the hemorrhage and edema resolve.
   • Mechanical entrapment of the inferior rectus or inferior oblique muscle or adjacent connective and fatty tissue in the fracture area. Diplopia is usually present when looking both upward and downward (double diplopia). In these cases, the traction test and differential reposition test of the eyeball are positive. Diplopia may subsequently decrease if it was caused mainly by entrapment of connective tissue and fatty tissue, but usually persists if the muscles are directly involved in the fracture.
   • Direct trauma to extraocular muscles in combination with a negative traction test. Muscle fibers usually regenerate and normal function is restored within 2 months.
4. Enophthalmos occurs with severe fractures, although it usually appears several days after the swelling has begun to resolve. Without surgical intervention, enophthalmos may increase for up to 6 months due to post-traumatic degeneration and tissue fibrosis.
5. Ocular lesions (hyphema, angle recession, retinal detachment) are usually uncommon but should be excluded by careful slit-lamp examination and ophthalmoscopy.

Diagnosis of blast fracture of the orbital floor

1. CT in the coronal projection is particularly useful in assessing the extent of the fracture, as well as in determining the nature of the soft tissue density in the maxillary sinus, which may be filled with orbital fat, extraocular muscles, hematoma, or polyps unrelated to trauma.
2. The Hess test is useful in assessing and monitoring the dynamics of diplopia.
3. The binocular visual field can be assessed using the Lister or Golgmann perimeter.

Treatment of blast fracture of the orbital floor

Initially conservative and includes antibiotics if the fracture affects the maxillary sinus.

The patient should be advised against blowing their nose.

The subsequent treatment is aimed at preventing permanent vertical diplopia and/or cosmetically unacceptable anophthalmos. There are three factors that determine the risk of these complications: fracture size, herniation of orbital contents into the maxillary sinus, and muscle entrapment. Although there may be some confusion among the features, most fractures fall into one of the following categories:

• Small cracks without hernia formation do not require treatment, since the risk of complications is insignificant.
• Fractures affecting less than half of the orbital floor, with small or no hernias, and positive dynamics of diplopia also do not require treatment until anophthalmos greater than 2 mm appears.
• Fractures involving half or more of the orbital floor, with incarceration of orbital contents and persistent diplopia in the upright position should be operated on within 2 weeks. If surgical intervention is delayed, the results will be less effective due to the development of fibrous changes in the orbit.

Surgical treatment technique

• transconjunctival or subciliary skin incision;
• the periosteum is separated and lifted from the orbital floor, all trapped orbital contents are removed from the sinus;
• the orbital floor defect is restored using a synthetic material such as supramid, silicone or Teflon;
• the periosteum is sutured.

CT scan shows postoperative status after reconstruction of right burst fracture using plastic implant.

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"Burst" fracture of the medial wall

Most medial orbital wall fractures are associated with orbital floor fractures. Isolated fractures are rare.

Symptoms of a medial wall fracture

• Periorbital subcutaneous emphysema, which usually develops during nose blowing. Due to the possibility of orbital infection with sinus contents, one should try to avoid this method of emptying the nasal cavity.
• Changes in ocular motility, including adduction and abduction, if the medial rectus muscle is trapped in the fracture.

Treatment involves releasing the trapped tissue and repairing the bone defect.

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Orbital roof fracture

Ophthalmologists rarely encounter orbital roof fractures. Isolated fractures caused by minor trauma, such as falling on a sharp object or a blow to the eyebrow or forehead, are more common in young children. Complicated fractures caused by severe trauma, combined with displacement of the orbital rim, as well as damage to other craniofacial bones, are most common in adults.

An orbital roof fracture manifests itself within a few hours as a hematoma and periocular chemosis, which may spread to the opposite side.

Extensive bone defects with downward displacement of fragments usually require reconstructive surgical interventions.

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Fracture of the lateral wall of the orbit

Ophthalmologists rarely encounter acute fractures of the lateral wall. Since the outer wall of the orbit is stronger than the others, its fracture is usually combined with extensive facial injuries.

Symptoms of Lateral Wall Fracture

• Displacement of the eyeball axially or downwards.
• Large fractures may be associated with non-bruit-related ocular pulsation due to transmission of cerebrospinal fluid pulsation, best detected by applanation tonometry.

Treatment of lateral wall fracture

Minor fractures may not require treatment, but it is important to monitor the patient to rule out the possibility of CSF leakage, which can lead to meningitis.

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