Fractures of the Orbit

History

• Mechanism of injury

• Previous eye/orbital surgery

• Other injuries

• Other illnesses/medications (Only in the most urgent circumstances, e.g., an entrapped extraocular muscle, should surgery be undertaken with the patient on anticoagulation.)

Physical Examination

• Vital signs

• Examination of the eye by an Ophthalmologist is strongly recommended when an orbital fracture is suspected.

• Vision (in each eye separately)

• Ductions movements of eyes in all directions volitionally, or forced, by the examiner with toothed forceps

• Enophthalmos/exophthalmos (measure with a Hertel or other exophthalmometer if possible)

• Existing lacerations, lids malposition, or scars

• Other associated soft tissue injuries

Imaging

• Fine cut orbit or maxillofacial computed tomography (CT) without contrast with coronal plane reconstruction

• Type of fracture

  • Zygomatic maxillary compound fractures (ZMC)

  • Le Fort 2/3

  • Frontal

  • Naso-orbito-ethmoidal (NOE)

  • Blowout

Force applied to the lower midface region produces variations of the classic fracture patterns described by Le Fort. Rarely do Le Fort fractures occur precisely as he described or symmetrically; however, these divisions help guide repair and provide an orderly and predictable approach. Le Fort II fractures, discussed in more detail in Chapter 186 , traverse the maxillary sinus, orbital floor, medial wall, and nasal bones. Le Fort III fractures, also called craniofacial dysjunction, involve the zygomatic bones in the lateral orbital walls, the floor and medial orbital walls, and the nasal bones. Although an air-fluid level noted on CT in one maxillary sinus suggests a sinus or orbital fracture, when this sign is present in both maxillary sinuses, one must assume the presence of a Le Fort II or III fracture until careful examination has proved otherwise. All Le Fort fractures also cause some measure of malocclusion.

Application of significant force to the upper midface area can lead to telescoping nasal fractures and NOE fractures. The hallmark of these injuries is traumatic telecanthus, with the normal intercanthal distance being about 35 mm or less. Fracture lines generally travel posteriorly through the medial orbital walls. The most urgent issues with these fractures involve possible leakage of cerebrospinal fluid with associated meningitis and trauma to the brain and the possibility of involvement of the optic canals posteriorly. Careful consideration must be given to the urgent need for decompression. Repairing these fractures requires re-establishing the normal anatomic relationships of the medial canthi. These injuries are discussed further in Chapter 186 .

ZMC fractures involve force directed posteriorly over the malar eminence or zygomatic arch. They were formerly referred to as “tripod” fractures, but this term is not entirely accurate, because this bone articulates in five places, even though two of the five generally do not require fixation during reduction. The characteristic facial deformity of a displaced ZMC fracture is flattening of the malar eminence, with or without apparent enophthalmos, and difficulty opening the mouth completely.

The remaining fractures involving the orbit (fractures of an orbital wall without associated rim fracture) are referred to as blowout fractures. Smith and Regan first described them in 1957 after observing a patient who had been hit in the periorbital area by a hurling ball.

• Size of fracture

  • If this is small and/or minimally displaced, surgery may not be indicated.

  • If there is a linear wall fracture, there is a risk of entrapment of an extraocular muscle or periorbita.

Indications

• The first four types of fractures are covered in Chapter 186 .

• Entrapped extraocular muscle mandates immediate open reduction internal fixation.

• Large (>2 cm ² ) or displaced fractures should be offered repair to treat/prevent enophthalmos, NOT to prevent diplopia (which will almost always resolve on its own).

It is generally accepted that fractures involving more than 50% of the orbital floor are likely to cause later enophthalmos. Displaced fractures with an area of 2 cm ² or greater are most significant: Approximately 1 cm produces about 1 mm of enophthalmos, and at a 2 mm or greater difference in projection of the globes, an aesthetic defect is noticed. The area of the medial wall fracture must be accounted for when making this rough calculation; although the medial wall is repaired less frequently, it contributes to later enophthalmos. A recent series of fractures of the orbital floor found that pediatric patients with large fractures who underwent surgery were much less likely to develop enophthalmos than their conservatively managed counterparts but that some children who presented with initial enophthalmos resolved over the following 6 months. In the pediatric population, it is acceptable to defer surgery except in patients with acute enophthalmos, muscle entrapment, or vertical dystopia.

Contraindications

• Systemic comorbidity

• Hyphema or traumatic optic neuropathy

  • Wait at least 5 days for hyphema to clear to prevent rebleeding.

  • Wait up to 6 months for traumatic optic neuropathy, which often improves on its own.

• Frank infection in periorbital area or sinus

Preoperative Preparation

• CT scan available

• Decide what implant material to use and how/whether to fixate.