16: Orbital Fractures

CHAPTER 16
Orbital Fractures

Eric Nordstrom,1 Michael R. Markiewicz,2 and R. Bryan Bell3

1Department of Oral and Maxillofacial Surgery, Oregon Health and Science University; and Head and Neck Surgical Associates, Portland, Oregon, USA; Department of Oral and Maxillofacial Surgery, Anchorage Oral and Maxillofacial Surgery, Anchorage, Alaska, USA

2Department of Oral and Maxillofacial Surgery, Oregon Health and Science University, Portland, Oregon, USA

3Providence Cancer Center; Trauma Service/Oral and Maxillofacial Surgery Service, Legacy Emanuel Medical Center; Oregon Health and Science University; and Head and Neck Surgical Associates, Portland, Oregon, USA

Reconstruction of traumatic orbital defects and restoration of pre-traumatic orbital volume.

Indications for Reduction of Orbital Fractures

  1. Entrapment demonstrated with a positive forced duction test
  2. Significant increase in orbital volume
  3. Dystopia (vertical or horizontal)
  4. Enophthalmos
  5. Binocular diplopia that lasts longer than 10–14 days
  6. Foreign body
  7. Hard and/or soft tissue loss: orbital floor defect of greater than 1 cm or greater than half of the orbital floor surface area

Contraindications

  1. Medically unstable
  2. Edema significant enough to limit clinical exam (relative contraindication)
  3. Globe rupture or hyphema, or other forms of ocular trauma
  4. Active infection

Anatomy

  • Bones composing the orbit (7): Maxilla, palatine, sphenoid (greater and lesser), zygomatic, frontal, ethmoidal, and lacrimal. The superior orbital fissure separates the greater and the lesser wings of the sphenoid bone
  • Contents of the superior orbital fissure: CN III, IV, V1 (nasociliary, frontal and lacrimal branches of the ophthalmic nerve), and VI; sympathetic fibers from the cavernous plexus and the inferior and superior ophthalmic veins
  • Contents of the inferior orbital fissure: CN V2 (maxillary nerve), zygomatic nerve, infraorbital nerve, parasympathetic fibers from the pterygopalatine (Meckel’s) ganglion, the infraorbital vessels and emissary veins connecting the inferior ophthalmic vein to the pterygoid venous pl
  • Contents of optic canal: Optic nerve, meninges, sympathetic fibers, and the ophthalmic artery.

Important orbital wall landmarks

  1. The optic nerve is located 42 mm, on average, from an intact adult infraorbital (inferior orbital) rim
  2. The anterior ethmoidal foramen-artery is located 24 mm posterior to the infraorbital rim and anterior lacrimal crest
  3. The posterior ethmoidal foramen-artery is located 36 mm posterior to the infraorbital rim and anterior lacrimal crest

Transconjunctival (Retro-Septal) Approach

  1. The patient is placed under general anesthesia with either oral or nasal intubation depending on the nature of the associated facial fractures and the need for maxillomandibular fixation (MMF).
  2. The patient is positioned within a Mayfield headrest to allow for manipulation of the head during the procedure.
  3. The patient is prepped with ophthalmic betadine solution (betadine scrub is not recommended for mucous membranes application) and draped. Lacrilube and corneal shields are placed.
  4. Local anesthesia containing a vasoconstrictor is injected at the sites of the proposed incisions. A higher concentration of local anesthetic should be utilized to decrease the volume injected and minimize distortion of the soft tissue architecture.
  5. The lower lid is retracted anteriorly with a Desmarres lid retractor (see Figure 16.9 in Case Report 16.1). A malleable retractor is used in conjunction with the corneal shield to retract the globe posterosuperiorly. Care is taken to avoid excessive globe pressure. Additionally, the anesthesiologist should be informed that there will be pressure on the globe to alert him or her of the possibility of decreased pulse rate (oculocardiac reflex).
  6. The transconjunctival incision is initiated lateral to the medial puncta and 5 mm anterior to the scleral- conjunctival interface with a protected needle tip or Colorado tip bovie. The incision transects mucosa directly overlying the infraorbital rim. Once the mucosa is transected, the postseptal approach (Figure 16.1) results in herniation of peri-orbital fat within the incision site. Herniated fat is retracted posteriorly with an orbital or malleable retractor. Dissection proceeds toward the periosteum overlying the infraorbital rim. The periosteum is transected and reflected to expose the infraorbital rim/floor of the orbit. Care is taken to not transect the inferior oblique muscle as it passes between the nasal (medial) and central fad pads.
  7. All displaced fractures (rim and floor) are exposed. Subperiosteal dissection is performed anterior to the transconjunctival incision to expose the infraorbital rim (Figure 16.10, Case Report 16.1) and posteriorly to expose any defects within the orbital floor. The transconjunctival incision may be extended laterally (Figure 16.2) to the zygomaticofrontal suture if additional exposure of the lateral orbital rim is necessary. A lateral canthotomy may be employed if sufficient exposure of the lateral rim cannot be achieved without stretching the lateral orbital tissues excessively.
  8. If additional exposure of the medial orbital wall is necessary, the transconjunctival incision may be extended medially (Figure 16.2), posterior to the caruncle (transcaruncular incision), and extended along the medial orbital wall. The transcaruncular incision is placed along the conjunctival groove just posterior to the lacrimal sac and semilunar fold. The incision can be extended along the medial orbital rim for approximately 12 mm. A subperiosteal tissue ­dissection is utilized to expose the medial orbital rim and orbital wall.
  9. All orbital rim fractures should be exposed to include adjacent uninvolved bone for adequate fixation. All orbital floor fractures should ideally have an area of intact bone circumferentially surrounding the defect.
  10. All areas of tissue entrapment are carefully freed from the orbital floor defect with a blunt-tipped elevator (Cottle or freer elevator) prior to the placement of any orbital fixation devices (Figure 16.3).
  11. Orbital fixation devices include orbital rim plates, stock titanium orbital meshes, stock preformed titanium orbital reconstruction plates, and custom, prefabricated implants. Orbital rims are typically fixated prior to orbital floors. Orbital rim plates are adapted to the orbital rim and fixated to the uninvolved adjacent orbital rim bone once reduction is obtained. Orbital floor devices are placed, ensuring that all edges of the orbital floor device are positioned on solid bone and with no entrapment of orbital tissues beneath the device (Figure 16.3; see also Figure 16.11, Case Report 16.1). The posterior ledge of an orbital floor device requires a minimum of a 2–3 mm purchase. The orbital floor device is evaluated for adequate antral bulge reconstruction, orbital volume restoration, and intact bone along the periphery of the device prior to fixation.
  12. The orbital floor device can be fixated with self-drilling 4 mm screws along the infraorbital rim (provided the rim is intact). If an orbital floor device cannot be placed without entrapment of tissues, a molded piece of smooth alloplastic material can be utilized if the defect is not excessively large to accept the material ­without ­distortion. Once materials have been fixated, the orbital soft tissue around the margins of the device are reevaluated to ensure no tissue entrapment, and a fin/>
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Jan 18, 2015 | Posted by in Oral and Maxillofacial Surgery | Comments Off on 16: Orbital Fractures
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