Maxillary Fracture

Etiology

The etiology of maxillary fractures varies depending on the socio-economic status of countries, sports cultures, motor vehicle regulations, and other laws.

Adult distribution of maxillary fractures tends to be predominantly a result of high-risk behavior such as interpersonal violence or road traffic accidents (RTAs).[2] The most common of the 2 is RTAs, of which motorcycle incidents are most frequent (73.6%) compared to motor vehicle incidents (9.5%).[1]. A large portion of these injuries occurs in the context of alcohol use (53%) or illicit drugs (47%). Interpersonal violence and assault, with or without the use of weapons, are commonly reported and comprise 19% of all maxillary fractures in a Swiss study of 471 patients.[3]

Sporting injuries account for 6% to 33% of maxillary fractures. The etiology is very much dependent on the sports culture within the country of study. Gaelic football (35.3%), football (22.3%), rugby (12.4%), and equine sports (12.4%) are chiefly responsible for the maxillary sporting injuries in Ireland, for example. In Italy, Germany, and France, football is the main cause. Conversely, in countries such as Switzerland and Austria, skiing is the most common cause of sporting injuries.[4]

For the pediatric and geriatric cohorts, the main cause of maxillary fractures is falls.[2] Lefort fractures are rare in the pediatric cohort and tend to present in major trauma cases, such as motor vehicle accidents, where a high-velocity impact is expected. Amongst the geriatric population, these injuries are often linked with other significant morbidities, increased severity of the fracture, and a higher risk of mortality.[2]

Epidemiology

A Malaysian study of 473 patients revealed a significant prevalence of maxillary injuries presenting in males (82.2%). The mean age was 30.6 years, with the youngest at seven months and the eldest at 87 years. The age group most affected was 11 to 20 years (34.5%), followed by 21 to 30 years (23.3%).[1] This is thought to be due to the increased likelihood of participation in high-risk activities, contact sports, and interpersonal violence. A study at Royal Perth Hospital, Western Australia, also supported a prevalence in males (87%), with an average age of 27 years. However, this male predominance decreases in the elderly cohort of patients, most likely because falls become the most common cause of fractures in general in the elderly population.[3] Among patients younger than 18 years of age, the likelihood of fractures increases with age, possibly as a result of greater involvement in high-risk activities and changes in the anatomy.[2] There is no dominance in men among the younger age groups, but this appears during later childhood years and adolescence. Facial fractures in children under the age of 5 are rare, making up 1.4% of cases.[5]

Pathophysiology

A study in New Zealand of 25,000 patients with facial fractures revealed a higher portion involved the midface (63.5%), and only 3.3% involved the upper third.[2] Of the midface, the zygomatic arch is the most vulnerable due to its prominence. The transmission of physiological forces during impact is distributed along the facial buttresses, and these are more likely to occur during a fracture [2]. A review of 93 facial trauma patients showed that infraorbital foramen was affected in 56.9% of cases, and displacement of the orbital floor was present in 86% of cases. Significant displacement of the floor occurred in a small portion of patients (21.5%). Muscle entrapment was noted in 15.1% of cases and herniation of adipose tissue in 24.4%.[6] An Iranian paper on 561 facial fractures reported that these injuries often present with others such as cranial fractures (29.5%) or other orthopedic fractures (71.5%).[7]

It should also be noted that the presence of dentures in the upper arch can alter the distribution of forces on impact, thus altering the fracture patterns. In addition, upper dentures may behave similarly to a splint and, if undamaged, can protect the alveolar bone and palate on impact. The absence of teeth is often associated with maxillary resorption, making them more susceptible to fracture.[8] Pediatric cases are less common than adults due to the less brittle nature of their bones, which can withstand considerable tensile stress or plastic deformation before fracturing.[5] As the child grows, the craniofacial ratio decreases from 8:1 at birth to 2:1 as an adult.[9] The facial position also becomes more prominent, increasing the risk of the facial structures taking the force of the impact. Pneumatization of sinuses reduces the thickness of the facial bones, making them more susceptible to fracture. In addition, infants begin to lose their subcutaneous fat that cushions the bones from the impact of trauma.[5]

History and Physical

When a patient presents with a suspected maxillary fracture, immediate assessment of the patient is key, as there may be concurrent life-threatening injuries. A primary survey of the patient is needed, including an advanced trauma life support (ATLS) assessment. The resuscitation team may be required in the immediate management of the patient. Once the patient is in a stable condition, a thorough history of the trauma is needed. It is important to ascertain if the patient lost consciousness or has any other signs of head injury, as neurological care would be a priority. Care must be taken to note the time the patient last ate, and their medications, in case surgery is indicated.

A secondary survey of the patient should be carried out to assess the trauma and for other concurrent injuries.

• The extra-oral examination should include recording of pain, swelling, bleeding, bruising, and epistaxis.
• The head and neck portion of the secondary survey includes examining, palpating, inspecting, and auscultating. Lacerations should also be recorded for debridement and closure as necessary, and exploration considered, and objects or debris may be present.
• Paraesthesia and anesthesia should be noted, particularly as a baseline prior to any surgery, to assess for nerve damage or bruising.
• Midface trauma will commonly present with a maxillary branch of the trigeminal nerve (V2) paresthesia.
• Step deformities or depressions, when the patient is assessed from all planes, can indicate a displaced fracture.
• Assessment of the eye should include any uni-ocular and bi-ocular diplopia, subconjunctival hematoma, visual acuity, and restricted eye movement, with any concerns consequently escalated to ophthalmology.
• Mouth opening can be restricted either due to hematoma causing trismus or due to impinging of the depressed zygoma onto the condyle

Of particular concern are orbital fractures concurrent with fractures of the maxilla. Generally, when paired together, the inferior orbital floor will be fractured, as this bone is particularly thin and weak, and this will create an area of drainage into the maxillary sinus. In cases where this is not present, blood and fluid can collect posterior to the globe and cause a retrobulbar hematoma, which warrants immediate surgical intervention with a lateral canthotomy and inferior cantholysis. It is worth noting that the diagnosis of a retrobulbar hematoma is a clinical diagnosis of a frozen globe. Pressure from tonometry often is between 50 and 70. 

Patients who have sustained a Lefort I fracture classically present with mobility of the tooth-bearing segment of the maxilla, altered occlusion, or damage to the teeth.[10] The maxilla is often floppy and free-floating when the fracture is complete and easy to manipulate, and very obvious if the patient tries to talk. Lefort II fractures have a pyramidal shape fracture pattern, and patients may present with orbital involvement, including orbital hematoma, epistaxis, and possibly cerebral spinal fluid rhinorrhea. Often the inferior orbital rims are affected, and fractures of the orbits are present.[10] Letort III fractures involve nasal bones, lateral orbital walls, pterygoid processes, and zygomatic arches. Patients may present with complete separation of the midface and the cranium or orbital complications.[10] Patients who have sustained zygomatic-maxillary complex fractures may experience edema, subconjunctival hemorrhage, periorbital edema, and enophthalmos.[11] Four percent to 12% of ZMC fractures result in major ocular injuries and minor ocular injuries are seen in 63% of patients. A detailed eye assessment by an ophthalmologic consultant should be considered if you suspect any injuries, including open globe, lens dislocation, retrobulbar hematoma, or hyphema.[12] An expert tip in conducting this assessment is to use your fingers and hands to wiggle and manipulate bony segments. It may be slightly uncomfortable for the patient, but it is the best way, combined with a computed tomography scan, to diagnose facial fractures, particularly of the maxilla and mandible.

Evaluation

The initial evaluation of the patient should be focused on immediate life support and securing the patient’s airway as facial trauma can commonly compromise the airway. It is also important to assess patients for potential cervical spine and head injuries, in particular, if the injury has been sustained from a high-velocity mechanism. Spinal fractures and dislocations have been associated with approximately 1.4% of Lefort fractures and 1% of spinal cord injuries.[10] A basic eye assessment is of paramount importance as maxillary fractures can result in severe ocular injuries, including retrobulbar hemorrhage, optic nerve compression, and retinal detachment. This can highlight any concerns that may require escalation to an opthalmologist for detailed assessment or clinical intervention. Up to 4.5% of ocular injuries caused by midface fractures require ophthalmologic surgery; therefore, evaluation of the eyes is prudent.[10]

Imaging is critical for the identification and diagnosis of the maxillary fracture as well as for planning the repair of the fracture. Options include plain film radiographs, computed tomography (CT), and magnetic resonance imaging (MRI).[13] Three-dimensional imaging has the advantage of showing the degree of displacement of fractures as well as a clearer view of damage to neighboring structures, such as the impinging of adipose tissue, muscle, and nerves. If a zygomatic-maxillary complex fracture is suspected, then occipitomental views 15/30 are used to assess this fracture.[14] However, with pediatric patients, it may be difficult to perform and interpret these plain films, which may lead to diagnostic delay of the facial fracture, therefore in children, CT imaging may be the preferred method.[13] If Le Fort fractures are suspected, and there are concerns that the fracture involves the orbit or orbital floor, then the gold standard is computed tomography.[11]

CT is the gold standard when examining bone for fractures. Plain films are appropriate if operating in an austere environment or there is restricted access to a CT scanner, but should not be considered first-line. MRIs are rare in a trauma setting and are not helpful when examining bony structures. A common pitfall with CT scans is not specifying the size of cuts. The finest possible cuts should be obtained, often 0.5 mm or 0.625 mm, in all views (axial, sagittal, coronal). The standard 2.5 mm cuts obtained from head CTs are much too big and will miss many fractures. A 3-dimensional reconstruction should also be obtained as often this will help elucidate fractures that might not be obvious when just examining slices from a single view.

Treatment / Management

The acute management of the patient is vital, and this may require the resuscitation team, including a cricothyroidotomy or tracheostomy to secure the airway. Midface fractures are a relative contraindication to nasal intubation, and these patients will eventually need an airway that does not go between the teeth to allow for reconstruction. However, with glide scopes and fiberoptic scopes, some anesthesia providers are comfortable nasally intubating these patients. Another option is a submental intubation when done with a surgical team. Essentially, the patient is orally intubated, an incision is made under the chin in the submental area, and the tube pulled through.

The main treatment aims for maxillary fractures are to preserve function and esthetics. The timing of treatment is also important, as esthetic defects may be difficult to appreciate in the acute phase post-trauma, and it is important to let the soft tissue swelling settle before surgery.[11] Conservative treatment is indicated for minimal, non-displaced fractures where there are no esthetic or functional concerns, or in the case of medically unstable patients where a general anesthetic is too high of a risk.[11] Conservative management would include regular analgesia, a soft or no chew diet, avoiding further trauma, and avoiding the introduction of negative pressure (such as nose blowing).(B3)

Absolute indications for surgery include concerns over the orbit and its contents, in particular, if a retrobulbar hemorrhage is causing compression optic nerve. This may present with diplopia, proptosis, chemosis, and loss of vision.[11] Other indications for surgery include esthetic defects and concerns regarding the occlusion. If a maxilla is fully fractured and grossly mobile, it must be fixated and reconstructed. Management of Lefort fractures aims to restore the facial projection and height as well as the occlusion. Surgical management involves maxillomandibular fixation, fracture exposure, fracture reduction, plate fixation, and soft tissue repair.[10] A study in Northeast Iran reported open reduction and internal fixation as the most common treatment with no complications (sensory defects, occlusion, or mouth opening) found in these patients. The authors cite the reason for this success as being due to the stable and precise anatomic reductions this technique allows.[7](B2)

Differential Diagnosis

Differential diagnoses for maxillary fractures include other head injuries such as the orbital floor, dentoalveolar fractures (including fractured teeth), hematomas, bruising, and trauma-related edema.

Prognosis

The prognosis of a patient sustaining a maxillary fracture depends on several factors, including the severity of the fracture and location, concomitant injuries, and the ability to sustain the airway after the injury. The prognosis in terms of function and esthetics after the injury depends on the severity of the injury, the method of surgery used, the skill of the surgeon, and the post-operative care of the patient.[11] Generally, Lefort fractures have an excellent prognosis with open reduction and internal fixation.

Complications

Mortality is a complication of maxillary fracture. Lefort fractures were found to have a mortality rate of 11.6%, and simple midface fractures had a mortality rate of 5.1%. However, this depends on the mechanism of the injury, the severity, and the presence of associated injuries.[10] Maxillary fractures, in particular, Lefort fractures, are also associated with significant visual problems (47%), diplopia (21%), and epiphora (37%). Other common complications include infection, trismus, facial nerve deficits, malunion, and facial asymmetry. Infraorbital nerve injury is reported in 30% to 80% of patients with ZMC fractures resulting in altered sensation along its course.[11] It is also important to note that key factors in preventing complications include sound surgical technique as well as patient education concerning post-operative care and follow-up.[11] Another key area of complication is malocclusion. Even with excellent surgical technique, the bite can be off ever so slightly, which the patient can perceive. This can generally be easily corrected in the post-operative phase using elastics if arch bars are present, and if needed, consulting with an orthodontist.