What Are NOE Fractures?

Nasoorbitoethmoid (NOE) refers to the anatomical complex involving the nasal, orbital, and ethmoid bones of the face. NOE fractures usually result from high-impact blunt trauma to the nasal region forcing depression of the nasal bones into the orbital and/or ethmoid bones.

While the NOE complex typically refers to these associated bones, NOE fractures may include damage to bones, blood supply, nerves, and other supporting structures of the mid-facial region. The force and point of impact determine the extent of injuries. Commonly associated causes of NOE fractures include falls, motor vehicle accidents, and contact sports.

NOE Complex Anatomy

While NOE complex commonly refers to the three main structures mentioned, it actually encompasses six categories of facial structures.

Bones are one of the major components of the NOE complex. These include:

• Nasal bones
• Nasal process of the frontal bone
• Nasal process of the maxilla
• Lesser wing of the sphenoid bone (also known as orbitosphenoid bones)
• Lacrimal bone
• Lamina papyracea (also known as orbital lamina of the ethmoid bone)
• Cribriform plate and perpendicular plate of the ethmoid bone

Other components of the NOE complex include:

• Sinus cavities formed from the bones listed above
• Medial canthal tendon, located in the inside corner of the eye, which connects bone to eyelids
• Nasal lacrimal duct components (lacrimal fossa, lacrimal sac, superior, and inferior canaliculi)
• Nerves (ophthalmic, maxillary, olfactory, and ethmoid)
• Arteries (ethmoid and maxillary arteries)
• Structures associated with the orbital bone (orbital fat, medial rectus muscle, superior oblique muscle, and trochlea)
• Buttresses of the face (areas of increased thickness that serve as support structures for other facial structures such as the eyes, dentition, airways, and muscle)

Signs and Symptoms

As you can infer from the many anatomical structures involved, there are many possible complications that can result from an NOE fracture.

The most common symptoms experienced include:

• Diplopia (double vision)
• Visual disturbances
• Pain in the eye, forehead, and nose
• Forehead paresthesia (abnormal sensations such as burning, itching, or numbness)
• Nasal congestion
• Dizziness or vertigo
• Anosmia (loss of smell)

There are also several physical signs that your healthcare provider will be looking for, including:

• Severe epistaxis (nose bleed)
• Epiphora (overflowing tears, signaling that the lacrimal duct is not draining appropriately)
• Ocular injury (globe rupture or ruptured eye, lens dislocation, retinal detachment, or vitreous hemorrhage)
• Cerebrospinal fluid (CSF) leak (noted as clear fluid draining from the nose)
• Traumatic telecanthus (increased distance between the pupils or inside corner of the eye)
• Periorbital ecchymoses (also called "raccoon eyes")

Prevalence

NOE fractures represent approximately 5% of facial injuries in adults and 16% of facial injuries in children. From these NOE fractures, approximately 60% will include some sort of eye injury.

Being in a motor vehicle accident with unrestrained passengers increases the risk of an NOE fracture occurring.

Diagnosis

Rapid diagnosis of NOE fractures is necessary in order to reduce long-term complications as well as aesthetic deformities. During the initial assessment, it is important for your healthcare provider to differentiate an NOE fracture from an isolated nasal, orbital (eye), or ethmoid labyrinth (ethmoid sinus) injury.

Prior to any NOE fracture-related assessments, you will have a full-body trauma evaluation. This will help ensure the most emergent risks are identified—in particular, adequate circulation, airway control, and breathing will be assessed. Proper precautions to protect your cervical spine may have already been initiated, as an injury to your cervical spine is also possible with this type of injury.

Head and Face Assessment

Initial head and face assessment begins with inspecting for ecchymoses (bleeding underneath the skin), any soft tissue injury, or any misaligned facial bones.

A likely next assessment will be the intercanthal distance, which is the measurement of the distance between your medial canthus (inside corner of your eyes). The typical distance is around 29 to 35 millimeters (mm), which is approximately half the distance between both pupils. You will be diagnosed with telecanthus if the distance is greater than 40 mm.

Further medial canthal tendon testing may include the bowstring test. Your healthcare provider will grab your eyelashes and pull your eyelid laterally away from your nose while palpating the tendon in the corner of your eye. If your medial canthal tendon is intact, resistance will be felt. However, if the tendon has torn away, there will be no tension felt. This test is important in helping to stage the severity and type of an NOE fracture.

Nasal Evaluation

A nasal exam may require suctioning to clear any congestion prior to inserting a speculum or endoscope. Your healthcare provider will be looking for mucosal (lining of the inside of the nose) tears, deviated septum, hematomas, or CSF leak.

If your healthcare provider notes clear or straw-colored fluid draining from your nose, or suspects that the back wall of sinus cavities has been damaged, they will test a drop of fluid on a piece of gauze or surgical towel and look for a "halo" effect. In this test, the CSF spreads faster than other fluid, which creates a haloed image.

The diagnostic laboratory test to check for CSF in nasal drainage is the beta-2 transferrin assay.

Primary and secondary Jones dye tests may be performed to determine patency of the lacrimal duct. In these tests, your healthcare provider can use a fluorescent dye to determine if the dye remains in the eye or is transported through the lacrimal duct system into your nasal passages.

CT scans are the gold standard for rapid identification of NOE fractures. X-rays are very limited in their usefulness and a thorough physical exam is often more beneficial. Using two different CT views (axial and coronal), thorough viewing of the NOE and any intracranial complications can be visualized.

Treatment

Due to the many facial structures involved in the NOE complex, repairing an NOE fracture is one of the more challenging surgical reconstruction procedures. Complications related to surgeries to repair NOE fractures mirror NOE fracture symptoms with the addition of scarring and infection.

NOE fractures are grouped into three different severity categories based on the fracturing of bones and other structures in relation to the medial canthal tendon as follows:

• Type-I fractures: A single large fragment with the medial canthon tendon still attached; also known as a unilateral Markowitz type 1 fracture
• Type-II fractures: May be either unilateral or bilateral; involves multiple fragments of bone; one fragment remains attached to the medial canthal tendon
• Type-III fractures: Similar to type-II fractures, but there is a detachment of the medial canthal tendon from the fragments

In type-I and type-II fractures, the nasal bones may or may not be fractured when fracturing is only on one side. In type-II fractures that involve bilateral fractures, nasal bone fracturing is commonly present. In most type-III fractures, the nasal bones are also fractured.

Related to the complexity of the surgeries, surgical interventions will start at the base of the skull (for stability) and the surgeon will work their way toward the mid-face. Early repairs will include realignment (reduction) and plating before proceeding to further repairs. Special attention is required in type-III fractures to reconstruct the orbital wall (bones around the eye socket) and reattachment of the medial canthal tendon.

In type-I and type-II, only minimal wiring and plating may be required. Repairing the lacrimal duct system may require insertion of a tube to stabilize the duct.

Treatment of NOE fractures can be very successful, however, you may still have several scars ranging from small to large depending on the severity and location of fractures. Soft tissue damage can also affect the cosmetic look of your face.