Chapter 57: Orbital Fractures

Introduction

Orbital fractures are injuries frequently encountered both acutely in the Emergency Room as well as in the office as chronic conditions. They are seen in isolation or in association with other head and neck injuries. This chapter will cover the clinical presentation, evaluation, examination findings, and management of orbital fractures organized from an anatomical perspective. The bulk of the discussion will focus on floor fractures, as these are the most frequent orbital fractures encountered. Other orbital fractures will then be discussed in a more succinct fashion to highlight the unique features based on their anatomic location. Basic orbital anatomy will not be discussed; for a review of orbital anatomy please refer to Chapter 58.

Orbital Floor Fractures

Background

1. Orbital floor fractures are the most common orbital fractures encountered.

   1. Most common location is posteromedial floor (maxillary bone), medial to infraorbital neurovascular bundle.

2. Blow-out fracture: floor fracture with intact orbital rim.

3. Floor is shortest orbital wall, in shape of equilateral triangle.

4. Mechanism:

   1. Smith and Converse: cadaveric study (1956)¹

      1. Blunt trauma (usually object smaller in diameter than orbit) pushes orbital contents posteriorly.

      2. Resultant increase in intraorbital pressure causes fracture at weakest point: posteromedial orbital floor (hydraulic theory).

   2. Buckling theory: direct blow to orbital rim causes buckling at weakest point of orbital floor.

5. Blow-in fracture: direct trauma to orbital rim causing bone fragment to be displaced into orbit (rather than into maxillary sinus); presents with exophthalmos, not enophthalmos.

Clinical Presentation

1. Symptoms: pain, blurred vision, binocular vertical/oblique diplopia.

2. Signs of periocular injury

   1. Eyelid edema

   2. Ecchymosis

   3. Subcutaneous or orbital emphysema

   4. Subconjunctival hemorrhage

   5. Enophthalmos (volume expansion) or exophthalmos (soft tissue swelling/edema)

   6. Globe ptosis

3. Ocular injuries

   1. Corneal abrasion: foreign body sensation, photophobia, blurred vision

   2. Traumatic iritis: photophobia, blurred vision, brow ache

   3. Hyphema: layer of blood in anterior chamber

      1. May have associated problems with intraocular pressure

   4. Lens dislocation: blurred vision. May occlude pupil causing angle closure glaucoma

   5. Retinal detachment: acute, painless loss of vision. Associated with flashes of light and visual field defect

   6. Commotio retinae: injury to outer retinal layers caused by shockwave from blunt trauma with resultant edema. May cause blurred vision if macula involved

   7. Open globe injury

4. Motility defects

   1. Trapdoor Fracture:²

      1. Small floor fracture.

      2. Orbital pressure causes orbital soft tissue to protrude through defect.

      3. Orbital bone recoils faster than soft tissue, trapping soft tissue in defect.

      4. Resultant motility restriction with greatest limitation in upgaze.

      5. Vagal symptoms: nausea, vomiting, bradycardia.

      6. May cause ischemia to extraocular muscles (EOM) and later fibrosis and restrictive strabismus.

      7. Most common in children due to more flexible bones (greenstick fracture- “white eyed” blow-out fracture).

   2. Contusive injury to EOM may cause generalized restriction in motility.

   3. Retrobulbar hemorrhage may cause orbital compartment syndrome: proptosis, pain, loss of vision, and frozen globe (complete restriction of EOM).

Evaluation

1. Basic examination

   1. Visual acuity: vision assessed with ...