This article presents an overview of surgical management for complex midfacial fractures for the practicing otolaryngologist–head and neck surgeon. Discussion includes the important anatomic relationships; pathophysiology; clinical features; pertinent physical examination findings; imaging; surgical approaches; and techniques for repair of zygomaticomaxillary complex, orbital, naso-orbital-ethmoid, and Le Fort fractures.
Key points
- •
The midface is composed of several paired vertical buttresses and horizontal buttresses that protect vital organs, such as the brain, optic nerves, and brainstem. Damage to the midfacial buttress system causes functional and cosmetic deformity.
- •
High impact trauma to the midface causes complex fracture patterns. These include zygomaticomaxilary complex, orbital wall and floor, naso-orbital-ethmoid, and Le Fort fractures.
- •
Diagnosis of midfacial fractures requires a thorough physical examination and high-resolution computed tomography scanning.
- •
The goal of surgical treatment is to restore the bony infrastructure of the midface while disrupting the least amount of soft tissue.
Introduction
The craniofacial skeleton is designed to support and protect critical organs, such as the eyes, optic nerves, brain, and brainstem. This is especially true of the midface, which consists of the paired zygomas, orbits, maxilla, and nasal bones. Each of these components is susceptible to complex fractures with high-impact injury. Distinct patterns, such as the zygomaticomaxillary complex (ZMC), orbital, naso-orbital-ethmoid (NOE) complex, and Le Fort–type fracture, occur with blunt trauma and result in cosmetic and functional deformity. Diagnosis requires a thorough physical examination and high-resolution computed tomography (CT) scanning. Depending on the amount of displacement or bone loss, treatment may vary from simple observation to open reduction and fixation. The goal of treatment is to restore the bony infrastructure to achieve optimal reduction while disrupting the least amount of soft tissue.
The midface can be described as several paired vertical (nasomaxillary or medial, zygomaticomaxillary or lateral, and pterygomaxillary or posterior) and horizontal buttresses (frontal bone and supraorbital rims, nasal bones and inferior orbital rims, and the hard palate) ( Fig. 1 ). The thicker vertical buttresses resist functional stresses (biting), whereas the thinner horizontal buttresses protect organs and define facial shape, but are relatively weak and collapse on impact. Restoration of the facial buttresses is an important concept in fracture management. Priority is given to disrupted buttresses to restore facial height (vertical buttresses) and projection (horizontal buttresses). Complex fractures of the midface may result in cosmetic and functional deformity. Thus, there are two aspects to consider during repair. First, there must be proper realignment of the bones to recreate aesthetic form and occlusal function. Second, a systematic fixation must be accomplished through rigid fixation by plates and screws. This fixation is designed to maximize the amount of stability created at the time of repair to minimize callus formation, infection, and any shifting in the surgical positioning. The challenge for the reconstructive surgeon is to restore patients to their preinjury form and function. New developments and improved understanding of fracture management have significantly improved outcomes. This article explores surgical approaches and techniques for repair of complex midfacial fractures.
Introduction
The craniofacial skeleton is designed to support and protect critical organs, such as the eyes, optic nerves, brain, and brainstem. This is especially true of the midface, which consists of the paired zygomas, orbits, maxilla, and nasal bones. Each of these components is susceptible to complex fractures with high-impact injury. Distinct patterns, such as the zygomaticomaxillary complex (ZMC), orbital, naso-orbital-ethmoid (NOE) complex, and Le Fort–type fracture, occur with blunt trauma and result in cosmetic and functional deformity. Diagnosis requires a thorough physical examination and high-resolution computed tomography (CT) scanning. Depending on the amount of displacement or bone loss, treatment may vary from simple observation to open reduction and fixation. The goal of treatment is to restore the bony infrastructure to achieve optimal reduction while disrupting the least amount of soft tissue.
The midface can be described as several paired vertical (nasomaxillary or medial, zygomaticomaxillary or lateral, and pterygomaxillary or posterior) and horizontal buttresses (frontal bone and supraorbital rims, nasal bones and inferior orbital rims, and the hard palate) ( Fig. 1 ). The thicker vertical buttresses resist functional stresses (biting), whereas the thinner horizontal buttresses protect organs and define facial shape, but are relatively weak and collapse on impact. Restoration of the facial buttresses is an important concept in fracture management. Priority is given to disrupted buttresses to restore facial height (vertical buttresses) and projection (horizontal buttresses). Complex fractures of the midface may result in cosmetic and functional deformity. Thus, there are two aspects to consider during repair. First, there must be proper realignment of the bones to recreate aesthetic form and occlusal function. Second, a systematic fixation must be accomplished through rigid fixation by plates and screws. This fixation is designed to maximize the amount of stability created at the time of repair to minimize callus formation, infection, and any shifting in the surgical positioning. The challenge for the reconstructive surgeon is to restore patients to their preinjury form and function. New developments and improved understanding of fracture management have significantly improved outcomes. This article explores surgical approaches and techniques for repair of complex midfacial fractures.
Overview
The body of the zygoma forms the malar prominence. It is an important aesthetic feature and is also the most anterior projection of the lateral face, thus at high risk for injury. The strong zygoma serves two purposes. First, it is the attachment for the powerful masseter muscle, which is essential to mastication. Second, the zygoma serves as the cornerstone of support for the vertical buttress system of the midface (see Fig. 1 ). The bones that articulate with the zygoma tend to be weaker and trauma often results in fractures at its suture lines: the zygomaticofrontal superiorly, the zygomaticotemporal posterolaterally, the zygomaticomaxillary medially, and the zygomaticosphenoid posteriorly ( Fig. 2 ). These fractures are called ZMC fractures, and often tripod fractures; however, if all four sutures are involved, these fractures should be referred to as tetrapod fractures.
ZMC fractures are the second most common type of facial fracture in patients with blunt trauma after only nasal bone fractures. Because the amount of force applied to the fracture site differs, the amount of displacement and bone loss also vary. Thus, a broad spectrum of fracture patterns range from isolated nondisplaced zygoma fractures to severely displaced and comminuted ZMC components. There are several classification systems used to describe ZMC fractures. The Zingg classification ( Table 1 ) system groups them into three categories (A, B, and C). Type A injuries, the least common, are isolated to one component of the tetrapod fracture. They are further subclassified into A1 for zygomatic arch fractures, A2 for lateral orbital wall fractures, and A3 for inferior orbital wall fractures. Types B and C account for more than 60% of ZMC injuries. Type B fractures involve injury to all four of the supporting structures, and type C fractures are complex fractures with comminution of the zygomatic bone.
| Zingg classification for ZMC fractures | |
| A | |
| A1 | Isolated zygomatic arch fractures |
| A2 | Isolated lateral orbital wall fractures |
| A3 | Isolated inferior orbital wall fractures |
| B | Injury to all four suture lines |
| C | Comminution of the zygomatic bone |
| Markowitz and Manson classification for NOE fractures | |
| Type 1 | Single noncomminuted central fragment without medial canthal tendon disruption. |
| Type 2 | Comminution of the central fragment, but the medial canthal tendon remains firmly attached to a definable segment of bone. |
| Type 3 | Severe central fragment comminution with disruption of the medial canthal tendon insertion. |
| Le Fort fracture classification (all three involve the pterygoid bone) | |
| I | Transverse maxillary fracture. Fracture line separates the teeth from the upper face. Fracture line passes through the alveolar ridge, lateral nose, and inferior wall of maxillary sinus. |
| II | Pyramidal fracture, with the teeth at the pyramid base, and nasofrontal suture at its apex. The fracture arch passes through posterior alveolar ridge, lateral walls of maxillary sinuses, inferior orbital rim, and nasal bones. |
| III | Craniofacial disjunction. The fracture line passes through nasofrontal suture, maxillofrontal suture, orbital wall, and zygomatic arch. |
The zygoma is intricately associated with the orbit and with the exception of isolated zygomatic arch fractures, always include a component of the orbital floor ( Fig. 3 ). Inferomedially, the zygoma extends from the inferior orbital rim and broadly contacts the maxilla by the zygomaticomaxillary suture line to form another vertical buttress (see Fig. 1 ). The zygoma also contributes to the lateral and inferior orbital rims and the inferolateral orbital walls. Thus, minor displacement of the zygoma can significantly alter the position of the globe in the orbit and significantly impact the anteroposterior position of the globe. External impact to this area may cause orbital wall or floor defects. If the orbital rim remains intact, but the force of impact is transmitted to the bones of the floor, roof, and medial wall, an orbital “blowout” fracture results. In this case, the continuity of the inferior, lateral, and superior orbital rims remains intact; however, the force is transmitted to the weakest bones, usually the floor and medial wall ( Fig. 4 ). Diplopia is the most frequent complication of orbital floor defects. Others include limitation of ocular movement, infraorbital numbness, enophthalmos, and reduced vision or blindness.
The medial orbital wall is composed of the frontal process of the maxilla, the lacrimal bone, the orbital plate of the ethmoid bone, and the sphenoid body. The thin lamina papyracea separates the orbit from the ethmoidal sinuses and is easily damaged. The lacrimal sac lies anteriorly in the lacrimal groove formed by the maxilla and lacrimal bone. At the junction of the medial wall and orbital roof are the anterior and posterior ethmoidal foramina. The anterior and posterior ethmoidal arteries and nerves travel here and may contribute to intraoperative bleeding if not protected during repair. The medial rectus muscle is also closely associated with the medial orbital wall. An obvious sign of medial wall fracture is injury or entrapment to the medial rectus, which presents as reduced adduction or abduction. The medial canthal tendon, trochlea, and lacrimal drainage system are other important structures located medially in the orbit and are susceptible to injury with medial wall trauma.
The orbital floor comprises the maxillary, zygomatic, and palatine bones. The floor terminates at the posterior edge of the maxillary sinus. The inferior rectus muscle, which lies adjacent to the orbital floor, may become involved in fractures of the floor with subsequent motility disturbance. Beneath the floor in the maxilla is the infraorbital foramen, which transmits the maxillary branch of the trigeminal nerve (V2); thus, sensory deficit for the middle of the face often accompanies injury to the orbital floor.
It is important to understand the complex shape of the globe because its contents influence its position. Inferolaterally, the orbital floor is concave; however, medially it is more convex and becomes significantly convex posteriorly at the apex. The greater wing of the sphenoid forms the orbit posterolaterally and the lesser wing contributes to the optic canal posteromedially. Although the location of the optic canal protects it from most injuries, the optic foramen does travel toward the lateral orbital rim. Thus, laterally directed forces may contribute to blindness or visual impairment. The apex of the orbit includes the area lateral to the optic canal and houses cranial nerves III, IV, V, and VI as they enter the orbit. Compression of this area, the superior orbital fissure, causes dysfunction in these nerves, and is an ophthalmologic emergency.
The nasal bones are prominently positioned in the middle of the face. Deep to the nasal bones lie the ethmoid sinuses and the medial orbital walls. High-force trauma is transmitted through the nasal bones adjacent to the laminae papyracea and orbit. These provide little support and “crumple” on impact, thus allowing the nasal bones to telescope posteriorly while scattering the compressive wave into the ethmoid sinuses. The ability of these bones to crumple under high impact protects deeper vital structures, such as the brain and optic nerve, and illustrates the advantageous biomechanical design of this region.
NOE fractures are the most complex fractures of the face diagnostically and therapeutically. Delayed or inadequate treatment of this region results in deformity that can be only partially corrected, such as a shortened and retruded nose, shortened palpebral fissures, telecanthus, enopthalmos, epiphora, and ocular dystopia. The concept of the “central face” refers to injury in which the trauma to the solid nasal root is transmitted posteriorly resulting in a telescoping injury and nasal retrusion. The “central face” includes the attachments for the medial eyelids and the projection of the nose. The medial eyelids are attached by the medial canthal ligaments to the bone of the anterior and posterior lacrimal crests. When these are disrupted, the tendons are pulled laterally (and anteriorly and inferiorly), and the horizontal length of the eyelids is shortened leading to telecanthus (increased distance between the medial canthi, with normal interpupillary distance). Orbital hypertelorism, by contrast, is a congenital increase in the distance between the globes. This needs to be reconstructed adequately to withstand the constant lateral tension of the lids. Epiphora results from obstruction or disruption of any member of the lacrimal outflow system, which is closely related to the medial canthal tendon and the lacrimal and maxillary bones. Treatment is difficult, because persistent posttraumatic epiphora has been reported in almost one-third of patient’s with NOE fractures.
Numerous classification schemes have been used to describe NOE fractures. Markowitz and Manson created a classification system (see Table 1 ) that is based on the status of the medial canthal tendon and the degree of comminution of the fragment of lacrimal crest bone to which it remains attached ( Fig. 5 ). Type I fractures occur when a large central fragment containing the medial canthal ligament is separated from the surrounding bone. Type II fractures are associated with significant comminution, but the fragment containing the medial canthal ligament is still repairable. In type III fractures, the tendon is either detached or attached to an unusable fragment.
The maxilla extends from the anterior skull base to the alveolar ridge. Each maxilla is functionally and cosmetically important to the midface because together they form the medial portions of the infraorbital rims and anterior orbital floors and also provide support for the nasal bones. They also form the piriform apertures, and house the maxillary sinuses, nasolacrimal ducts, and dentition important for mastication.
Much of the understanding of patterns of maxillary fracture propagation in midfacial trauma originates from the work of René Le Fort. In 1901, he reported his work on cadaver skulls that were subjected to blunt forces of various magnitudes and directions. He concluded that there are predictable patterns of fractures after blunt injury (see Table 1 ). These fractures occur along three lines of weakness inherent in the design of the facial skeleton ( Fig. 6 ). Le Fort I fractures are known as the horizontal maxillary fracture and occur above the level of the maxillary dentition, separating the alveoli and teeth from the remaining craniofacial skeleton. Type I fractures cross the nasal septum, and are posteriorly completed through the posterior maxillary walls and pterygoid plates ( Fig. 7 ). Le Fort II fractures are known as the pyramidal fracture. They start on one side at the zygomaticomaxillary buttress and cross the face in a superomedial direction leading to a fracture of the inferior orbital rim and orbital floor. They traverse the medial orbit, cross the midline through the nasal bones, and then travel inferolaterally across the contralateral side of the facial skeleton. This causes a pyramidal-shaped inferior facial segment that is separated from the remaining craniofacial skeleton ( Fig. 8 ). Similar to Le Fort I, it fractures the nasal septum, the posterior maxillary walls, and the pterygoid plates. Le Fort III fractures cause complete craniofacial separation and occur at the level of the skull base, separating the zygomas from the temporal bones and frontal bones. These fractures cross the lateral medial orbits to reach the midline at the nasofrontal junction. Again, Le Fort III also disrupts the nasal septum and pterygoid plates. Most present day maxillary and complex midfacial fractures are not pure Le Fort fractures, but rather are a combination of the various types. Fracture lines often diverge from the described pathways and may result in mixed-type fractures, unilateral fractures, or other atypical fractures.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
