Naso-orbitoethmoid Complex Fracture
The naso-orbital ethmoid (NOE) complex is comprised of the nasal bone, the nasal processes of the frontal bone, the frontal processes of the maxillae, the lacrimal bones, the laminae papyraceae of the ethmoid bone, and the sphenoid bone. Fractures of the NOE complex often occur due to high energy impact to the mid-face and are usually seen in the context of pan-facial fractures.
High-velocity mid-face trauma such as motor vehicle accidents and interpersonal violence may result in an NOE fracture. Falls and sports injuries are less common causes of NOE fractures.
Patients who sustain any trauma to face are at risk of NOE fractures. The traumatic event is usually associated with high energy impact or force (e.g. motor vehicle accident).
A fracture of the bones of the NOE complex (i.e. nasal bone, frontal process of maxilla, lacrimal bones, ethmoid bones and sphenoid bone) may result from blunt trauma. The medial canthal tendon is often disrupted. NOE fractures rarely occur as an isolated fracture and is almost always seen in context of pan-facial fractures.
High-energy impact or trauma to the mid-face may result in an NOE fracture. It has been hypothesized that the thin nasal bones transmit force posteriorly to the lacrimal and ethmoid bones, which crumple and thus spare the contents of the cranial vault and orbits.
Avoid or mitigate trauma to the face. Seatbelts have been reported to decrease risk of maxillofacial injury in motor vehicle accidents. Protective gear such as full-face helmets for high impact activities may also reduce incidence of NOE fractures.
Markowitz and Manson Classification is the most used schema for classifying NOE fractures. It is based on the status of central fragment and medial canthal tendon (MCT).
- Class 1 – the MCT is attached to relatively large “central fragment” of fractured bone
- Class 2 – the MCT is attached to comminuted fragments of bone that are difficult to manipulate at the time of reduction
- Class 3 – comminuted central fragment with avulsion of the MCT from its bony insertion
NOE fractures are also classified based on if they are unilateral or bilateral.
Patients will typically report history of trauma to face. In children, trauma may be more mild than in adults.
Formal and complete ophthalmic exam must be performed to rule out globe trauma. Visual acuity and optic nerve function must be evaluated as early as possible. Complete orbital exam is required and serial exams may be necessary if there is evolving pathology such as an orbital hemorrhage. Palpation of the orbital rims may reveal step-offs and other bony defects that may indicate further orbital damage. Direct palpation of the MCT is the most important physical exam maneuver when evaluating for an NOE fracture. Mobility of the MCT indicates an NOE fracture that will require surgical intervention. Rounded canthi (“cow’s eye”) is another common sign of a dislocated fracture. Other common physical exam findings include traumatic telecanthus, narrowing of the horizontal palpebral fissure, periorbital and mid-face swelling and bruising, flattened nose with widened nasal dorsum (saddle-nose deformity), and subcutaneous emphysema due to air from the ethmoid cells infiltrating the soft tissues. Concomitant injuries associated with NOE fractures include telecanthus, epistaxis due to rupture of anterior ethmoidal artery, cerebrospinal fluid rhinorrhea due to fracture of cribiform plate, and nasolacrimal duct obstruction.
Clinical diagnosis can be made from history of facial trauma and associated physical exam findings, specifically mobility of the MCT. Computed tomography (CT) is utilized to assist in making the diagnosis and in classification of fracture.
Non-contrast CT scan of the face/orbits with thin cuts is the most useful imaging modality to evaluate for and classify NOE fractures. Coronal and axial scans are most useful for evaluation of the fracture. CT scan will show size and location of fracture and bone fragments and any associated fractures of orbit, face, and head. Other entities such as foreign bodies, hematoma, globe rupture, and optic nerve trauma may be found as well. 3D CT reconstruction may be helpful to define fractures and bony fragments for surgical planning.
- Ocular or periocular contusion
- Isolated orbital wall fractures (floor, medial wall, lateral wall, roof)
- Zygomatic-maxillary fractures
- Le Forte complex fractures
Nonmobile class 1 fractures are the only type that can be managed nonoperatively. Associated ocular, orbital, or lid trauma must also be addressed and treated appropriately (e.g. repair of lid laceration). Oral or IV steroids may reduce swelling but have not shown to benefit long-term outcomes.
Surgical intervention is common for NOE fractures. The bone fragment with attached MCT is assessed and the fracture is classified as indicated above. This classification, along with clinical judgment, determines the surgical intervention undertaken. Typically, class 1 fractures (large bone fragment) are reduced and stabilized with small plates. Class 2 fractures require reduction and plating and transnasal canthopexy to reduce bone fragment(s) with MCT attached. Class 3 fractures require reduction and plating, re-attachment of MCT, and transnasal canthopexy. In general, it is preferred to use smaller plates when possible.
If surgery is needed, the entire area must be exposed. A coronal incision is performed to expose the superior region of the NOE fracture. A transconjunctival lower lid incision is performed to expose the inferior region of the NOE fracture and orbital walls. A limited midline incision and upper buccal sulcus incision may also be performed if needed. After exposure, the surgeon can then directly assess if the bone fragment with attached MCT is large enough for direct plating. Class 1 fractures (large bone fragment) are reduced and stabilized with small plates. Class 2 and 3 fractures require reduction of bone fragments, plating, and transnasal canthopexy. The most important step is securing the MCT into good position superior and posterior to the lacrimal fossa. It is nearly impossible to over-correct the MCT position in the long-term, so it is advised to over-correct as much as possible while intra-operative. There are many techniques to secure the MCT and to create an insertion point for it. To secure the MCT, the surgeon can suture it to the medial canthal area from the posterior aspect of the flap or the surgeon may choose to directly loop the tendon to a suture near the lacrimal crest. One technique to create an attachment site is to drill holes (vertically oriented) 4-5mm apart near the anterior of the MCT insertion and drill to the same sites on the contralateral side. For a bilateral canthopexy, the surgeon can pass sutures from one side to the other and tie the sutures to each other. For a unilateral canthopexy, the suture is secured to screw or plate in the frontal region. For class 3 fractures, the surgeon can attach the MCT to the bone fragment with wire or heavy nylon suture, and then perform the transnasal canthopexy as described above. An alternative approach for class 2 or 3 fractures is to use a titanium canthal barb passed through skin or caruncle as the attachment site of the MCT. A stab incision is made just below the inferior canaliculus or directly in the MCT and the canthal barb is passed through the wound. A fixation plate is placed on the anterior portion of the rim and most posterior hole. The canthal barb wire is passed transnasally, superior and posterior to lacrimal fossa, and is then fixed to the plate on the contralateral side. If the fracture is unilateral, the wire can be placed between the screws holding the plate and under the plate. If a dorsal nasal graft is needed, it is most common to acquire a graft from cranial bone that is then plated or screwed into place. This may be difficult to do in the acute setting due to edema. A soft tissue bolster is necessary to provide external pressure to the medial canthal region during the healing process. External pressure is required so the degloved soft tissue does not fill with serum and blood which would prevent adherence between the skin and bone required to give normal contours in the medial canthal “valley”. To accomplish this, the surgeon can pass two sutures from the medial canthal region on one side to the other side beneath the nasal bones. These sutures are left very long. After the MCT is secured and the wound closed, dressing or packing material can be placed in the medial canthal regions and the sutures tied firmly over it to provide the necessary external pressure. This soft tissue bolster is left in place for at least a week, often longer. Alternative, percutaneous transnasal wiring of the MCT can be performed following bony reduction. Caution should be taken with any transnasal wiring procedure to avoid entering the cranial vault.
Surgical follow up
In the immediate postoperative period, avoid nose blowing and strenuous exercise. Patients are seen at 1 week and further depending on recovery. Patients must be reminded that ultimate postoperative healing outcome may not occur for months due to the edema, hematoma, damage to muscle, and boney fusion required.
Complications are typically related to the status of MCT and nasolacrimal duct. Persistent telecanthus is a common complication if the MCT was not able to be placed in good position. It is almost impossible to treat secondarily. Typically, the surgeon must refracture the area and reduce medial canthal bone fragment more medially. Epiphora secondary nasolacrimal duct obstruction is also common. Almost half of patients present with epiphora immediately postoperatively. The majority of these will resolve as the fracture heals and the swelling goes down, but 5-10% may persist. For this reason, the surgeon should treat epiphora secondarily, 6 months or more after fracture reduction.
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