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When we talk about extraconal pathology,

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we also include the discussion of orbital fractures.

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The orbital rim is the most anterior portion of the

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orbital floor and these two structures are the most

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common portions of the orbit to show fracture.

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These are followed by the medial orbital wall,

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also known as the Lamina Papratia.

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As you can imagine, if it's paper thin bone,

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it's going to have increased rate of fractures.

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The lateral orbital wall is less commonly fractured and

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the superior wall is the least commonly fractured.

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Many of these portions of the orbit may be involved

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in the Le Fort fractures. For example,

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Le Fort two involves the orbital floor

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and the medial orbital wall,

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whereas the Le Fort three fracture will involve,

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both the lateral orbital wall and the medial orbital wall.

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These Le Fort fractures also involve the pterygoid plates.

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Whenever we find fractures of the orbit,

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we also want to look for soft tissue injury

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to the globe, because globe injuries occur in 10% - 25%

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of patients who show orbital fractures.

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If we were to involve the superior wall of the orbit,

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we would worry about the potential for cerebrospinal fluid

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leakage, which can occur into the paranasal sinuses

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or into the orbit. As mentioned previously,

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the orbital floor is the most common site for orbital

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fracture and it is important to make the distinction as to

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whether or not the infraorbital nerve

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canal is involved with the fracture.

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I have to admit that sometimes I'm a little bit confused

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as to whether to call this portion of the orbit

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the inferior portion of the medial orbital wall,

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or the medial portion of the orbital floor.

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So, I usually say there is a fracture which affects the

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junction of the medial orbital wall and the orbital floor.

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We also describe, whether or not, the

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inferior rectus muscle is deviated below the plane of the

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natural course of the orbital floor, to describe

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potential entrapment. In this case,

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what we can see is that there is a large amount of orbital fat,

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which has herniated through the fracture site

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in what is called a trapdoor fracture, angling medially,

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and this, too, can lead to diplopia, secondary to

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tethering of the inferior rectus muscle.

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There is some controversy regarding the indications for

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surgery for orbital fractures, and that is at what point

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in time do we have to operate to repair the fracture?

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Enophthalmos greater than 2 mm, Hypoglobus,

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where the globe is displaced downward,

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and the presence of diplopia,

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are some of the indications,

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clinically, for repair of orbital fractures.

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Entrapment of the muscle that we see

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on the CT scan, also can lead to limited mobility with,

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or without diplopia, and may also be an indication

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for surgical repair of the orbital fracture.

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It's relatively uncommon to have optic neuropathy

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associated with orbital floor or medial orbital wall

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fractures, unless there is a large retrobulbar hematoma,

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at which time one can have orbital compression syndrome

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where the optic nerve may be compromised due to ischemic

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compression on the arteries and veins.

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Here is another opinion with regard to indications for

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surgery for orbital fractures. In this case, with the

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current opinions in otorhinolaryngology head and neck surgery,

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one sees that fractures that involve greater than

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50% of the extent of the floor,

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should be treated surgically,

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as well as a clinical finding, and that

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is the oculocardiac reflex or the Aschner reflex.

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This is a decrease in the heart rate, associated with

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traction applied to the extraocular muscles

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and/or compression of the eyeball, clinically.

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When this happens, it is considered to be an indication for

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surgical intervention with possible ischemic

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optic neuropathy. On the other hand,

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if we look at the oral maxillofacial opinion, they say it's

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relatively rare that one would have to

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emergently repair orbital fractures.

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And they say that this is because you can have problems

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with adhesions with orbital hematoma that can lead

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to scarring and making surgery more difficult.

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There is some benefit, however,

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in waiting because the acute hematoma and edema will

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resolve, and therefore you can wait for two weeks

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to three weeks, in which case you don't have to

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deal with the acute blood products and/or the surgical

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edema, the traumatic edema of the injury.

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In general,

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children get operated earlier because they have a higher

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rate of entrapment with the muscles herniating through

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the medial orbital wall or the orbital floor.

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There are also controversies in

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what to use for the surgery.

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You saw that we were shown examples of surgical mesh

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material that is metallic that has been used

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for repair of the orbital fractures.

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This then leads to considerable artifact, if one

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were to perform MRI scans in the future.

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And therefore, there is some disagreement as to whether or

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not that is the most beneficial as opposed

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to using autogenous grafts of iliac bone,

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alloplasts, that are non-resorbable material as opposed

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to what we use at Johns Hopkins Hospital,

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which is predominantly titanium mesh.

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Here are examples of that titanium mesh,

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nicely demonstrating reconstruction of the orbital floor,

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in a fracture that was medial to the infraorbital

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foramen, bilaterally.

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Here is the appearance on axial scanning of this titanium

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mesh with a portion of it that is supporting

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the medial orbital wall, as well.