Naso-orbital-ethmoid (NOE) fractures constitute a very complex group of fractures with regards to maxillofacial trauma. The NOE complex has a very delicate and intricate anatomical structure, and because of this, even the slightest damage to the complex can have catastrophic functional and aesthetic consequences.
This is especially complicated by the fact that the brain and the eyes are in very close proximity to the bones involved. The nasal bones, nasal septum, nasal processes of the frontal bone, maxillary frontal processes, ethmoid bone, lamina papyracea, lacrimal and sphenoid bones make up the NOE complex.
Etiopathogenesis
Blows to the central portions of the middle of the face with high energy and velocity are sufficient to cause NOE fractures. Motor vehicular accidents followed by interpersonal violent events are the most common etiological causes associated with fractures to the NOE complex. The NOE complex is particularly prominent anteriorly and this makes it fairly susceptible to injury from physical trauma. In contrast to other bones in the craniofacial area like the frontal or zygomatic maxillary bones, less energy is required to result in NOE fractures.
Telecanthus, which is an increased intercanthal distance of the eyes, is seen with NOE fractures and is due to displacement of the medial canthal tendon or MCT from its anatomic position. In order for telecanthus to ensue, the patient must have fractures in the medial and inferior orbital borders, in addition to the lateral nasal bone, fronto-maxillary junction and naso-maxillary buttress. The bony proportion displaced with the MCT may range from minimal distortion to extensive comminution, and it is the condition of the bone that may be used as a basis to classify NOE fractures into three categories.
In the first and simplest category of NOE fractures, Type I, there is no comminution of the bone and only the medial perimeter of the orbit is involved with the MCT. These fractures can be easily anatomically reduced by realignment of the bone. Type II fractures are typically complete. Moreover, they involve comminution of bone that is external to the MCT insertion and the preserved continuity of the MCT with the fractured large segment of the bone allows for its usage in surgical correction.
Type III fractures are those that are bilateral, complete and present with bone comminution and fracture line extension into the MCT insertion site. Due to the segment of fractured bone, to which the MCT is attached, being very small, it cannot be used in surgical reconstruction.
Clinical Presentation
The signs and symptoms associated with NOE fractures are proportional to severity of the degree of injury. Aside from obvious physical deformity that may be noted, patients may present with facial edema and ophthalmologic and olfactory deficits, such as double vision and loss of smell. Furthermore, these patients may have enophthalmos (i.e. displacement of the eyeball posteriorly) and epiphora (i.e. the overflowing of tears down onto the face).
Management
Diagnosis is done comprehensively with the help of radiographic imaging and the inclusion of details, such as the extent of the fracture, its location and displacement. Type I injuries are treated with a minimally invasive approach and trans-nasal fixation to reproduce symmetry of the mid facial region. Micro-plates or titanium meshes can be employed for type II injuries. Type III injuries, which are the most complex are very challenging with regards to repair. The end goal is to reconstruct the orbital borders and the MCT insertion site.
References
Further Reading
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