Maxillofacial Injuries: Clinical Characteristics and Initial Management

Authors: Brian Euerle, MD, Attending Physician, University of Maryland Medical Center; Assistant Professor, University of Maryland School of Medicine, Baltimore; and Brian Kelly, MD, Emergency Medicine Resident, University of Maryland Medical Center, Baltimore

Peer Reviewer: John P. Santamaria, MD, FAAP, FACEP, Medical Director, After-Hours Pediatrics, Affiliate Professor of Pediatrics, University of South Florida School of Medicine, Tampa

Patients with maxillofacial injuries represent the very core of the specialty of emergency medicine. This group encompasses all age ranges—from the very young child to the elderly— and a spectrum in the severity of injury. The patient also may have associated injuries and medical conditions; the emergency practitioner must be aware of these injury patterns and know how to manage them.

Emergency physicians (EPs) may evaluate, manage, and discharge the patient; however, other specialists are likely to be involved in the care of the patient, and therefore, the EP also must be aware of the appropriate referral patterns.

To adequately address the complexity and breadth of maxillofacial trauma, the current issue reviews the anatomy, recognition of common injury patterns, and initial stabilization. A second issue will address specific injuries in detail, diagnostic imaging, definitive management, and appropriate consultation and disposition strategies. The Editor

Introduction

Five to ten percent of all patients presenting to the emergency department (ED) do so because of a maxillofacial injury, therefore, maxillofacial trauma is an area of great importance to the practicing EP and emergency nurse.1,2 Although physicians from other specialties (e.g., plastic surgery, otolaryngology, and oral and maxillofacial surgery) may become involved in the care of the patient with a maxillofacial injury, it is the EP who performs the initial assessment, coordinates the patient’s care, and manages other injuries or medical conditions that may be present.3

Patients classified as having maxillofacial trauma can present with a variety of injuries, ranging from minor to life-threatening. Injuries classified as maxillofacial include 1) fractures to any of the facial bones; 2) soft tissue injuries to the face and intraoral structures, including lacerations, abrasions, and contusions; 3) dental injuries, including impaction, subluxation, avulsion, and fractures of the teeth or alveolar bone; and 4) temporomandibular joint dislocation.4 Injuries generally not classified as maxillofacial trauma include 1) injuries to the orbits themselves; 2) intracranial conditions such as closed-head injury, subdural and epidural hematomas, and traumatic subarachnoid hemorrhage; 3) skull fractures; and 4) cervical spine injuries. These injuries certainly may occur in the patient with maxillofacial trauma, however, and the ED practitioner also must be skilled in their management. These associated injuries in the head and neck area, as well as injuries to the other systems, such as the pulmonary system, can add greatly to the complexity and difficulty of patient management.5

Management of patients with maxillofacial trauma may be challenging to the ED for a variety of other reasons. This type of trauma may be associated with social or public-health issues such as child and elder abuse, interpersonal violence, alcohol-related violence, domestic violence, incorrect seatbelt and car seat use, and a lack of helmet use by bicycle and motorcycle riders.6–18 The urgency of some of these situations demands that they be addressed at the time of ED presentation. The EP and emergency nurse also need to be cognizant of the psychological issues that may result from maxillofacial trauma (e.g., posttraumatic stress disorder and the effects of altered facial appearance).19–21 Certainly, management of medical and surgical issues is the priority at the time of the ED visit; however, awareness of these psychological issues may be helpful in the overall management of the patient.

Etiology

Much of the published literature regarding assessment and management of maxillofacial injuries has come from military wartime experiences. During World War I, trench warfare dominated, therefore, the majority of serious wounds sustained by infantrymen were to the head and neck.22 These devastating facial injuries required dentists and general surgeons to review the anatomy of the face and develop innovative surgical reconstructive techniques. In 1917, the Surgeon General’s Office (SGO) conducted 3- to 6-week courses to train general surgeons and dentists to treat maxillofacial wounds.22 As a result of these wartime experiences, the SGO published abstracts in the literature, and the specialty of maxillofacial surgery began.

Although EPs seldom are called upon to care for wounded soldiers, maxillofacial injury has become a common complaint in EDs. Maxillofacial trauma most commonly is associated with motor vehicle crashes (MVCs) and assault; however, significant epidemiologic differences exist, depending upon the location of the treating facility and the mean age of the population in the catchment area.

There are almost 30 million more vehicles than licensed drivers in the United States; it is not surprising that MVCs accounted for 37,795 fatalities and more than 2 million injuries in 2001.23 Some reports suggested that nearly 75% of these injuries involved the craniofacial structures or the cervical spine.24 The enforcement of mandatory seatbelt laws and, more recently, the widespread incorporation of airbag restraint systems into automobiles have led to a significant reduction in MVC-related mortality; however, in persons age 35 years or younger, MVCs remain the most common cause of death or trauma.17

Assault is a common reason for ED visits. Domestic violence, child abuse, and altercations routinely result in facial injuries. The midface is the most common target of assailants, with injury typically resulting from a blow by a fist. The majority of injuries are isolated to the soft tissue; however, fractures of the nasal bones and mandible are quite common. Additionally, left hemifacial injuries are more common, owing to the greater prevalence of right-hand-dominant individuals.

Firearm-related injuries are the second leading cause of injury-related deaths in the United States.25 Approximately 115,000 firearm-related injuries occur annually; roughly 10% of these injuries occur to the face.25,26 This percentage increases to more than 50% if the injury was intentionally self-inflicted.25 The severity of injury depends upon the caliber of the weapon, the velocity of the projectile, and the range at which the patient was shot.27,28 Sixty-eight percent of firearm-related injuries in persons 15 to 24 years old result from interpersonal violence, while 78% of firearm injuries in older persons result from suicide attempts.26 With the help of firearm awareness programs, firearm-related injuries and mortality have decreased significantly. Nevertheless, firearm injuries remain a devastating problem in the United States.

Approximately 22 million children are injured in the United States annually. The number of injuries surpasses all other major diseases of children.29 Children are uniquely susceptible to maxillofacial injury because of their disproportionate cranial-body mass ratio.29 In young children, falls are the most common cause of facial injury.30 In older children, bicycle crashes and sports-related injuries dominate, with assault becoming more common with increasing age.30,31

Patients older than 65 years account for approximately 1% of maxillofacial trauma, and falls are the most common cause in this age group.8 Each year, nearly a third of individuals older than 65 years suffer a fall.8 In one retrospective review of 42 patients presenting to an ED with maxillofacial injury, 36 (85.7%) gave a history of falling. MVCs and elder abuse also are important causes to consider in elderly patients with facial injuries.

Anatomy

The anatomy of the maxillofacial area is quite complex, involving many organ systems. Differences exist between pediatric and adult patients, especially in dental anatomy. The ability to properly assess and manage the patient with maxillofacial trauma starts with a good understanding of the pertinent anatomy, which is best understood by division into the categories of skeletal, soft tissue, vascular, neurologic, and intraoral structures.

Skeletal. The facial area and its bones have typically been divided into upper, middle, and lower thirds (See Figure 1.).32 The upper portion of the face is that area overlying the frontal bone. The frontal bone forms portions of the roof and lateral wall of the orbit. Its thickened anterior portion forms the supraorbital ridges. The supraorbital foramen is located in this area and serves as a passageway for the supraorbital nerve. The frontal sinus is contained within this bone.

Figure 1. Skeletal Anatomy of the Facial Area

The middle third of the face is the most complex and is formed by the maxilla and the zygomatic, nasal, lacrimal, palatine, vomer, and inferior nasal concha bones.32 The maxilla is the largest bone in this portion of the face. The inferior portion of the maxilla (the alveolar process) serves as the attachment for the upper teeth. The maxillary sinus is located within the body of the maxilla. The maxilla is closely involved with the orbit, forming portions of the medial and inferior orbital rims, medial orbital wall, and orbital floor. The infraorbital foramen, containing the infraorbital nerve and artery, is located in the maxilla. The zygomatic bone forms the zygomatic arch and gives structure and shape to the cheek.32 It articulates with the frontal, temporal, maxilla, and sphenoid bones.The nasal bones give shape to the superior portion of the nose. They articulate with the frontal and maxilla bones.32 The lacrimal, palatine, vomer, and inferior nasal concha bones are smaller, minor bones that may be involved in maxillofacial trauma but rarely require specific management or attention when injured.

The lower portion of the face is dominated by the largest and strongest facial bone, the mandible.32 The mandible is made up of the body and two rami. The junction between body and ramus is referred to as the angle.33 The most anterior portion of the body is the symphysis. The body serves as the attachment for all of the lower teeth. The mental foramen, containing the mental nerve and artery, is located in the anterior portion of the body.

The superior portion of the ramus contains the condylar process and the coronoid process, which are separated by the mandibular notch. The condylar process articulates with the glenoid fossa of the temporal bone to form the temporomandibular joint. This joint contains a fibrocartilaginous disc within it and is surrounded by a fibrous capsule.32

Soft Tissue. The soft tissue of the maxillofacial region consists largely of skin, cartilage, and muscle. The skin of the face is attached loosely to the underlying structures, except in the area of the lower lateral cartilages in the tip of the nose.32 The skin of the eyelids is unique because it is especially thin and contains lacrimal, sweat, and sebaceous glands.32

Cartilage is found in the maxillofacial region in the ear and nose. In the ear, the auricle cartilage is located just beneath the skin and gives structure to the majority of the ear, except in the inferior portion, the lobule. The shape of the nose is formed largely by the cartilage in the lower half.32 The cartilages involved are the septal cartilage, the lateral nasal cartilage, and the greater and lesser alar cartilages.

The numerous muscles in the maxillofacial area are superficial and thus likely to be injured during trauma. The various muscles can be considered as several large groups.32

The muscles of facial expression constitute one group.32 These superficial muscles move the skin when they contract. Various muscles in this group are found in the neck, scalp, nose and mouth, and surrounding the eyes. The large, strong muscles of mastication move the mandible.32 Included in this group are the medial and lateral pterygoid, the masseter, and the temporalis muscles. This group can pull and manipulate fractures, and therefore, is important to the treating physician. The suprahyoid muscles are a group of small muscles attached to the hyoid bone.32 They move the hyoid bone, mandible, and tongue. Individual muscles in this group are the mylohyoid, digastric, geniohyoid, and stylohyoid muscles. The last group of muscles to be considered is that of the soft palate:32 the levator vel palatini, the tensor veli palatini, and the muscular uvulae. They act to manipulate the soft palate and uvula.

Vascular. The vascular supply to the maxillofacial region is rich and complex.2,32,34 The arterial blood supply originates with the bilateral common carotid arteries, which, in the neck, bifurcate into the internal and external carotid arteries.

The internal carotid artery continues through the neck with no branches. It enters the cranial fossa and serves largely to provide the brain with blood. Of importance is that the internal carotid artery will supply blood to the eye and eyelids, the upper face, and the nasal cavity through several branches. With the exception noted above, the majority of blood supplied to the maxillofacial region arrives via the external carotid artery.32 The external carotid artery gives off branches of the superior thyroid, lingual, facial, occipital, posterior auricular, and ascending pharyngeal arteries before terminally branching into the superficial temporal and the maxillary arteries.32

All venous blood drainage from the maxillofacial region occurs ultimately via the internal jugular vein, before it joins the subclavian vein.32 Superficial areas of the face are drained by the external and anterior jugular veins. The internal jugular vein drains the deeper structures.

Neurologic. The cranial nerves are numerous and complex; however, it is possible to concentrate on two in the patient with maxillofacial trauma—cranial nerves V and VII.32

Cranial nerve V (the trigeminal nerve) has both sensory and motor function in the maxillofacial region. The sensory function is provided by three divisions: the ophthalmic nerve, the maxillary nerve, and the mandibular nerve, which are responsible for sensation in the upper, middle, and lower portions of the face, respectively. One of the more notable branches of the maxillary nerve is the infraorbital nerve, which passes through the infraorbital foramen to provide sensation to the mid-portion of the face. An important branch of the mandibular nerve is the inferior alveolar nerve, which provides sensation to the mandibular teeth. The motor function of the trigeminal nerve is provided by branches of the mandibular nerve, which innervate the mastication muscles.

Cranial nerve VII, the facial nerve, has a largely motor function as it innervates the muscles of facial expression.32 This nerve has five branches—temporal, zygomatic, buccal, mandibular, and cervical—that travel to the various muscles of the face and neck.

Clinical Features and Evaluation

Prehospital Care. Emergency medical service (EMS) personnel routinely are called upon to care for patients with maxillofacial injury. As the point of first care, paramedics and emergency medical technicians perform critical interventions that can greatly influence patient morbidity and mortality. A careful, stepwise approach, including assessment of airway integrity, cervical spine immobilization, and control of ongoing bleeding, is important for patient survival.

Airway compromise is common with maxillofacial trauma and should be the primary concern of prehospital personnel. Initial assessment of injury severity can be misleading, necessitating vigilance, as airway compromise can occur rapidly due to aspiration of blood and gastric contents or from the progression of previously unrecognized injuries. Supplemental oxygen administered by facemask may be sufficient for patients with minor injuries. Adequate ventilation using bag-valve-mask (BVM) may be difficult to achieve, owing to disruption of anatomy and loss of structural support. Airway obstruction from posterior displacement of the tongue resulting from loss of anterior support is common with bilateral mandibular fractures and may require placement of an oral airway in the patient with an absent gag reflex.35–37 In patients with maxillofacial trauma, the oral airway should be inserted with the concavity toward the tongue after displacement of the tongue with a tongue depressor instead of the alternative method of insertion followed by 180º rotation. In general nasal airways should by avoided in patients with midfacial injury; it is not possible to visualize the entire path that the nasal airway will traverse.

The gold standard for definitive airway management by EPs remains orotracheal intubation. The safety of out-of-hospital rapid sequence intubation (RSI) performed by paramedics was questioned by researchers in response to the high incidence of transient hypoxia and bradycardia experienced by patients with severe closed head injury (Glasgow Coma Scale [GCS] score < 8) during intubation.38 This concern was based upon the finding that 84% of patients who developed hypoxia during RSI performed by prehospital care providers had initial oxygen saturation measurements in the normal range. However, because of anatomic problems associated with facial fractures, successful airway management with BVM ventilation may not be possible.5,36,37,39,40 Therefore, if airway protection is indicated in the field, out-of-hospital RSI should be attempted. Additionally, a recent study found that Combitube insertion as an airway salvage maneuver was highly successful after multiple failed out-of-hospital orotracheal intubation attempts.41 In general, blind nasotracheal intubation or nasogastric tube insertion should be avoided because of the possibility of intracranial tube placement associated with fractures of the cribiform plate or nasoethmoid complex.24,37,42,43

Cervical spine injury associated with maxillofacial trauma is well documented in the literature. An estimated 1–7% of patients with facial injuries have concomitant cervical spine injury.1,32,36,39,40 In a five-year review of 151 multitrauma patients with severe maxillofacial injuries (Injury Severity Score > 12; mean, 21.4) presenting to an urban Level I trauma center, the incidence of cervical spine injury was 7.3%.5 Therefore, before moving a patient with any likelihood of cervical spine injury, prehospital care providers should immobilize the patient’s neck with a semi-rigid cervical collar and a backboard with lateral head restraints. Care also should be taken to secure the patient’s body to the backboard in several places during transport to minimize cervical motion.

Bleeding from facial injuries can be brisk because of the extensive vascularity of the face and scalp and may cause life-threatening airway obstruction or hypovolemia. The reported incidence of severe bleeding varies greatly—from 1.25% to as high as 24.4%.44 Although bleeding from isolated facial injury rarely is significant enough to produce hemorrhagic shock in adults, children may experience massive blood loss and shock secondary to their smaller total blood volume. Initial control of bleeding from soft-tissue sources is best obtained by direct pressure when possible. Bandages with large quantities of gauze do little to slow bleeding and may mask the amount of blood loss. Persistent oral or nasal bleeding is common in patients with midfacial fractures. Ongoing nasopharyngeal hemorrhage may require placement of anterior nasal packing with petroleum gauze and unilateral or bilateral posterior nasal pressure balloons with a Foley catheter.44 Management of ongoing soft-tissue hemorrhage may require placement of interlocking sutures for temporary control.

Prehospital management also includes establishment of intravenous access and initiation of isotonic fluid resuscitation. Early volume resuscitation, commonly with normal saline or lactated Ringer’s solution, is vital for circulatory support and may prevent transient hypotension upon induction of anesthesia for RSI.

ED Care. After life-threatening conditions have been stabilized, a thorough history should be obtained from the patient, available witnesses of the incident, and EMS personnel. Obtaining an accurate history may be difficult, but details of the patient’s medical and surgical history, current medications, and allergies should be elicited if possible. A detailed description of the mechanism of injury will guide further evaluation. High-speed incidents, such as a MVCs, are likely to produce associated head and cervical spine injuries.33 Closed head injury should be suspected whenever a history of decreased level of consciousness or alcohol involvement is obtained.33 A detailed description of vehicle damage may increase suspicion for concomitant injuries. The use of seat belt restraints or the deployment of airbags is important, because the presence of these devices alone or in combination is associated with less severe maxillofacial injuries.17,18 It is essential to question women regarding the possibility of domestic-violence–related injury and potential pregnancy. Though less critical for initial management, the patient’s tetanus immunization status should be determined.33

Initial evaluation in the ED should proceed according to standard trauma evaluation protocol (Table 1). If the cervical spine is not immobilized already, an assistant should maintain in-line manual stabilization while the physician applies a semi-rigid collar.

Table 1. The LEMON Law

The primary survey is performed to ensure integrity of the airway, breathing, and circulation (ABCs). Careful assessment of airway integrity begins by asking the patient his or her name. Inspect the mouth and oral pharynx to assess intraoral bleeding, which can lead to aspiration of blood and airway compromise. Direct laryngoscopy to confirm correct endotracheal tube placement is necessary if the patient was intubated in the field. Inspection of the patient’s chest wall should include evaluation for symmetric chest rise. Auscultation of the lungs assesses air movement for bilateral equality. Tracheal position should be noted and tracheal auscultation performed. The presence of ecchymosis or stridor over the laryngeal cartilages may indicate significant upper airway injury, necessitating further management.

Tachypnea should be considered a sign of distress and requires careful monitoring. Tachycardia may be present as a physiologic attempt to maintain cardiac output in the setting of ongoing hemorrhage. Hypotension is a late finding indicating failed compensatory mechanisms. The presence of any gross neurologic deficits should be noted in addition to the calculation of the GCS score. Finally, the patient should be exposed completely, removing all clothing and accessories.

Direct laryngoscopy is the mainstay of emergency airway management. EPs routinely perform endotracheal intubation with great success. Recent literature suggests that EPs and anesthesiologists are equally successful in managing trauma patients’ airways.45 Failed intubation rates typically are less than 1% under ideal conditions.46,47

Although airway management in patients with facial trauma can be challenging, securing a definitive airway is crucial for patient survival. Aspirated blood, foreign bodies, displaced fractures, or direct trauma can compromise the airway. Conditions such as cervical spine injury, alcohol intoxication, or a full stomach may further complicate airway management.

Most emergency airways in the ED are managed by RSI. In the cooperative patient, the oral pharynx and facial anatomy should be examined to identify clues that may signify a difficult intubation using direct laryngoscopy, such as active intraoral bleeding or dental injuries. If obtained, a history of difficult intubations may be one of the strongest predictors of airway difficulty.48 Assessment of the distance between the upper and lower incisors as well as estimation of the distance from the inferior tip of the chin to the top of the hyoid bone may alert the laryngoscopist to a difficult airway. (See Table 1.)

RSI proceeds with selection of an induction agent and paralytic agent. A paralytic agent may be unnecessary in a patient with a depressed level of consciousness. An adequate bedside rigid suction catheter is essential for successful intubation in patients with maxillofacial trauma. Direct laryngoscopy followed by endotracheal tube placement with primary and secondary confirmation of correct position completes RSI. Methods of secondary confirmation include use of an end-tidal carbon dioxide detector or esophageal detector. External laryngeal manipulation of the thyroid cartilage with the laryngoscopist’s right hand (bimanual laryngoscopy) may improve visualization of the glottic opening if difficulty is encountered.46

Appropriate preparation ensures that a backup plan is available should RSI fail. Commonly used airway salvage devices include the 1) intubating laryngeal mask airway (LMA), 2) esophageal-tracheal Combitube, 3) gum elastic bougie, and 4) fiberoptic bronchoscope. Each device has advantages and disadvantages, but all have been used successfully in patients with maxillofacial injury.42,47,49,50 One or all of these devices should be within reach at all times when performing RSI.

In certain situations, the severity of the injury may necessitate establishing a surgical airway. In a review of 92 patients with maxillofacial gunshot injuries, 20 patients had a threatened airway on presentation to the ED. Of these 20 patients, 12 (60%) were intubated successfully, while eight (40%) required immediate surgical airways.51 Of the 72 patients initially evaluated as having a normal airway, 11% later required some form of emergency airway management, highlighting the importance of early airway protection.51

After completion of the primary survey and, if necessary, definitive airway management, the practitioner’s focus should turn to the secondary survey, with particular attention to the facial complex.

Soft Tissue Injuries. Evaluation and management of soft tissue injuries of the face deserve special attention. The importance of the delicate structures of the maxillofacial complex is not limited to physiologic function. The face is one of the most aesthetically appealing structures of the human body. The negative effect of facial deformities on social functionality is well documented.21 A thorough examination of all soft tissue injuries will minimize factors that may contribute to a poor aesthetic outcome. Soft tissue injuries of the face may result in a sensory or motor deficit if the trigeminal or facial nerve is involved (See Anatomy section.). The location of the injury in relation to the origin of the facial nerve will dictate the feasibility of microscopic nerve repair.

The extent of wound contamination should be recorded; the presence of a foreign body greatly increases infection risk. Inspect all wounds cautiously; sharp foreign bodies pose a threat not only to the patient but to the health care worker as well. Extensive wound contamination ("road rash") may result in traumatic tattooing if the wound is not scrubbed completely clean of all foreign particles. Failure to remove foreign bodies may result in discomfort and disfiguring scars. Carefully inspect the scalp. Matted hair with dried blood can make identification of underlying lacerations or abrasions difficult. Descriptive features of lacerations to the scalp include location, length, depth, and the presence or absence of ongoing bleeding. The presence of a bony step-off indicates a skull fracture.

Laceration to the orbital ridge or eyelid may result from blunt trauma. Inspect the wound to rule out the presence of periorbital fat. If present, the laceration should be considered to involve the orbital space, therefore, ophthalmologic consultation is needed. Other eyelid injuries that warrant consultation include 1) lacerations extending through the tarsal plate, 2) lacerations that prevent the patient from opening the eye, signifying involvement of the levator palpebrae superioris muscle or tendon, and 3) any potential injury to the lacrimal system.51

Inspect lacerations to the cheek for parotid duct or facial nerve injury. Stenson’s duct may be considered intact if parotid gland massage produces clear fluid from the parotid papilla located on the buccal mucosa opposite the upper second molar. Failure to express clear glandular fluid or the expression of blood with massage is indicative of duct injury. Surgical consultation is needed for injuries to the parotid duct or facial nerve injury resulting from lacerations located lateral to a vertical line running through the lateral canthus of the eye.51

Lacerations of the nose or ear can be particularly difficult to manage. There is little laxity in the skin of these cartilage-bearing structures. Inspect the nasal cavity for the presence of an intranasal laceration or septal hematoma. Lacerations extending through the auricular cartilage require special repair techniques to avoid a poor result. Auricular hematomas must be noted; surgical drainage is required to prevent cauliflower deformity and infection.

Intraoral soft tissue injuries may occur with maxillofacial injuries. Small lacerations of the tongue generally heal well without intervention. Large lacerations or those involving the tongue margins require a layered repair to provide hemostasis and preserve function. Lacerations of the lip extending through the vermillion border or involving the philtrum may warrant plastic surgery consultation for repair.

Dental Injuries. Injuries to the maxilla, mandible, and adjacent soft tissues commonly are associated with dentoalveolar injuries. Careful inspection of the dentition and gingival mucosa utilizing a gloved finger, a pair of tongue depressors, and a bright light source will identify most dental injuries.52 Account for all of the patient’s teeth; avulsed teeth may be displaced into adjacent soft tissues or become aspirated, swallowed, or simply lost at the scene.36 Chest and abdominal radiographs may be necessary to locate missing teeth.

Examination of the oral cavity begins with inspection. Remove all blood and debris from the oral cavity prior to examination. Record the location and size of soft-tissue injuries. The presence of an empty socket may indicate complete avulsion of the tooth. Gingival bleeding may occur as a result of laceration from an underlying fracture.

Ask the patient to close his teeth together to evaluate occlusion. Abnormalities of occlusion indicate an underlying traumatic injury. Each tooth is then palpated to evaluate for mobility. Abnormal mobility may indicate a subluxation (nondisplaced) injury or luxation (displaced) injury of the involved tooth.

Perform percussion of each tooth. Sensitivity elicited by percussion suggests a concussion injury in which the tooth generally is not mobile or displaced, but has sustained an injury.53

Fractures of teeth can be classified as crown fractures (involving the portion of the tooth above the gingival surface) or root fractures (involving the portion of the tooth below the gingival mucosa) (See Figure 2.). The Ellis classification system commonly is used to describe crown fractures. Ellis I fractures in-volve the enamel only; the tooth appears normal in color but has an obvious irregularity in the enamel surface. Ellis II fractures involve the enamel and dentin; the fractured surface may reveal a yellow center from exposed dentin surrounded by enamel. Also, the patient may complain of pain or sensitivity of the involved tooth. An Ellis III fracture involves the enamel, dentin, and pulp; bleeding from the pulp may be observed. Bacterial contamination of the pulp can result in necrosis of the pulp, necessitating endodontic therapy. Root fractures represent 0.5–7% of dentoaveolar trauma in permanent teeth. Suspect injury to the root when bleeding from the gingival sulcus is observed; however, these injuries are best detected with radiographs.53

Figure 2. Classification of Tooth Fractures

Mandibular Fractures. The mandible is one of the strongest of the facial bones; but, because of its prominent position on the face, it is one of the most frequently fractured.4,32,37,54 When taking the history from a patient with a suspected mandibular fracture, pay particular attention to the mechanism of injury; various types of mechanisms can cause specific injuries. During an MVC, the force generally is directed to the patient’s chin, which may cause fractures of the condylar and symphysis areas.36 Injuries from interpersonal violence are most likely to be in the left angle because most assailants are right-handed. MVC victims tend to have multiple or comminuted fractures because of the large forces involved, compared with assault victims who tend to have single, non-displaced fractures.32

The three questions presented below should be asked of every patient with a suspected mandible fracture; answers will guide the clinician in further evaluation.36

"Does your bite feel normal?" Any change in the patient’s occlusion makes a mandibular fracture very likely.32 It is the patient’s impression of a change that matters. Patients are very sensitive to very small changes from their normal bite.

"Is your lip or chin numb?" Decreased or absent sensation in these areas is likely the result of involvement of the inferior alveolar nerve, which runs through the ramus, angle, and body of the mandible before exiting through the mental foramen. Numbness on one side localizes the fracture to one of the segments of the mandible, on the same side.36

"Does your jaw hurt when you open and close your mouth?" Mandible fractures are especially painful while opening and closing the mouth, because of distraction of the fracture segments.36 In addition, a patient with a mandible fracture may be unable to open or close his or her mouth fully.

Physical examination of the patient starts with inspection of the external portion. Asymmetry of facial appearance can be a clue to the presence of a fracture. The mandible is a relatively superficial bone, and its borders generally can be palpated quite well for areas of tenderness, swelling, or step-offs. An important part of the examination is inspection of the external auditory meatus. At times the condyle can be displaced posteriorly and may disrupt the skin of the external meatus.36 After the external meatus is inspected, palpation may be performed by inserting a fingertip and pressing lightly in an anterior direction.36 This action can detect injury to the temporomandibular joint.

Next examine the intraoral area. Carefully inspect the lower teeth for any gap or step-offs between them; if noted, a mandible fracture is present.36 Hematomas on the jaw or floor of the mouth commonly are associated with mandible fractures. Careful palpation of the mandible may reveal swelling, tenderness, or sharp step-offs of the normally smooth mandible. The physician can use both hands to grasp the mandible and check for areas of mobility. Ask the patient to open and close his or her mouth and examine the bite for malocclusion.

Mandible fractures in the condylar and subcondylar area can be difficult to diagnose. Patients with this type of injury can present with malocclusion but no other evidence of a fracture. However, on opening the mouth, deviation of the jaw to the side of the fracture is evident.36

Maxillary Fractures. Maxillary fractures occur less commonly than mandibular fractures. They generally are caused by mechanisms of injury involving greater amounts of force, involve more facial edema, and likely are associated with other midface fractures.36,37

The Le Fort classification classically has been used to describe maxillary fractures. The Le Fort I fracture is the least severe and involves separation of the maxillary alveolus from the upper midface at the level of the piriform aperture (See Figure 3.).

Figure 3. Le Fort I Fracture

In the Le Fort II fracture, a central nasomaxillary segment is separated through the inferior orbital rims and nasofrontal junction (See Figure 4.).

Figure 4. Le Fort II Fracture

The Le Fort III fracture has a fracture line at the upper portion of the zygomaticofrontal junction, orbital floors, and nasoethmoid area (See Figure 5.).

Figure 5. LeFort III Fracture

These fracture patterns often may be mixed; for example, a Le Fort III can be combined with a Le Fort I. Another variation is an asymmetric pattern with, for instance, a Le Fort II fracture on one side and a Le Fort III on the other.

The history and physical examination follow the same basic approach as in the patient with a suspected mandible fracture. The patient with these fractures often reports malocclusion. Fac-ial numbness can be a clue; however, in this case the numbness involves the upper lip, side of the nose, or upper gingiva because of the involvement of the infraorbital and superior alveolar nerves.36

The physical examination consists of inspection for swelling, abrasions, lacerations, echymoses, and asymmetry. The maxillary bone is palpated, especially along the orbital rims and the bridge of the nose.36 Instability is assessed by grasping and attempting to manipulate the anterior maxillary teeth. Any movement of the maxilla indicates a fracture. The level of the movement can give a preliminary indication of the classification of the fracture. With a Le Fort I fracture, only the central portion of the maxilla should be mobile. In a Le Fort II, the bridge of the nose will move along with the maxilla, and in a Le Fort III, the bridge of the nose, infraorbital rims, and zygomas will show movement.36

Zygoma Fractures. The zygoma is one of the most frequently fractured facial bones, because of its prominent position in the facial skeleton.36,37 There are several classification schemes for zygoma fractures; many are complex and of little use to the EP. One general scheme of classification that is useful is the broad division into zygomatic and zygomatic complex fractures.32

A zygomatic fracture involves just the zygoma bone itself, such as an isolated zygomatic arch fracture. A zygomatic complex fracture involves the zygoma itself as well as parts of the surrounding four bones with which the zygoma articulates—the temporal, orbital, maxillary, and frontal.32,36 The zygoma forms a significant portion of the lateral and interior walls of the orbit as well as portions of the maxillary sinus,36 thus, fractures of the zygoma can disrupt these surrounding structures.

During the history, direct attention to several areas. Numbness of the lower eyelid or upper mouth is again important, as the infraorbital nerve may be involved in a zygomatic complex fracture.36 Painful opening of the mouth may be present because of the attachment of the masseter muscle to the zygomatic body and arch.36 Finally, a report of binocular diplopia is important, because it commonly accompanies zygomatic fractures.32

Physical examination often can be less revealing with this type of fracture because of large amounts of swelling and edema that may accompany it. However, there are several important findings on physical examination. Because of the prominent position of the zygoma in the face and the large role it plays in giving shape to the midface, a depressed fracture of the zygoma often causes a flattening of the malar area, which is evident despite the edema. Bleeding from the tissue disruption in a zygomatic fracture may cause preorbital or subconjunctival ecchymosis or epistaxis.32 When the patient complains of diplopia, examination may reveal limitations of extraocular movements, which are caused by edema or muscle entrapment.

Orbital Fractures. Orbital fractures can be caused in two ways. An orbital blowout fracture results from a direct blow to the orbit; the resulting hydraulic pressure of the compressed orbital tissues fractures the bone surrounding the orbit (See Figure 6.). This is likely to occur in the medial aspect of the orbital floor, which is the weakest area of orbital bone. As a result, orbital contents can herniate into the maxillary sinus, resulting in enophthalmos or limitation of eye movements and diplopia with upward gaze. The other type of orbital fracture is caused by direct trauma to the orbital rim, resulting in a fracture of the involved bone.

Figure 6. Orbital Blow-out Fracture

During the history, any complaints related to abnormal vision should be sought, including diplopia, blurry vision, loss of vision, or change in field of vision. Again, numbness of the lower eyelid or upper lip is important because the infraorbital nerve may be involved.

Physical examination should focus on the orbit and the surrounding orbital rim. A complete ocular and funduscopic exam should be performed. It is important to detect any ocular injury such as hyphema, corneal or globe lacerations, impaired visual acuity or extraocular movements, and proptosis. One third of patients with a comminuted zygomatic complex fracture have a severe ocular injury.36 Careful palpation of the orbital rim will reveal any step-offs or localized tenderness.

Nasal and Nasal-Orbital-Ethmoid Fractures. Nasal and nasal-orbital-ethmoid fractures are considered together here, but they should be differentiated clearly from each other, because they differ in severity.

Nasal bones are fractured frequently because of their prominent position and the minor force needed to fracture them. However, they are generally minor injuries, therefore, some patients may not seek evaluation or treatment. Nasal injuries can involve the nasal bones, cartilage, or both.

A nasal-orbital-ethmoid fracture is more severe and involves not only the nasal bones but also portions of the frontal, maxillary, nasal, and ethmoid bones.36,37 Fractures can involve the posterior wall of the frontal sinus and result in dural tears with cerebrospinal fluid rhinorrhea or brain tissue injury.

The physical examination starts with inspection of the nose and surrounding area. Observe the nose for symmetry and swelling. One important portion of the examination is assessment of the intercanthal distance (i.e., the distance between the medial commissures of the eyelids). It can be increased in nasal-orbital-ethmoid fractures due to the positional disruption of the medial canthal tendon; this distance normally measures 30–34 mm.36

Inspect the nose internally with a nasal speculum to look for bleeding, lacerations, or septal hematomas. Palpation of the nose may reveal tenderness, step-offs, mobility, or crepitus.

Temporomandibular Joint Dislocation. Dislocation of the temporomandibular joint (TMJ) may be caused by trauma, generally by a blow to the chin while the mouth is open. It also may occur from a non-traumatic mechanism such as yawning, laughing, laryngoscopy, or prolonged dental work.36,37

The TMJ is a hinge and sliding joint. During normal mouth opening, the condyle rotates and translates forward to the area of the temporal eminence. In a dislocation, the condylar head slides farther forward and becomes locked anterior to the temporal eminence. Trismus and spasm of the masticatory muscles prevent the condyle from sliding back. A TMJ dislocation may occur in a unilateral or bilateral pattern.

Obtaining a history from a patient with a TMJ dislocation can be difficult because he may have difficulty speaking; however, any history of trauma or an inciting event should be sought. The possibility of a dystonic reaction should be considered. TMJ dislocation may be a chronic problem in some patients, so it is important to ask about any prior occurrences.

A TMJ dislocation usually is evident on physical examination. The patient will present with difficulty talking and inability to close the anterior teeth. The patient with bilateral TMJ dislocations will present with a symmetric open anterior bite; in a unilateral dislocation, the jaw will be deviated to the unaffected side.

Palpation of the TMJ area may reveal the condylar head in an abnormal position below the zygomatic arch. If the dislocation resulted from trauma, the remainder of the mandible, intraoral, and facial areas should be inspected carefully and palpated to assess for an accompanying fracture.

Conclusion

ED physicians commonly are confronted with patients who have sustained maxillofacial trauma through a variety of mechanisms. A comprehensive understanding of anatomy and special considerations for the initial stabilization of these patients, such as airway management and cervical spine stabilization, allows the ED physician to confidently manage even the most critically injured patient. The next issue will focus on imaging considerations and techniques, definitive management, consultation and disposition decisions, and special circumstances for patients who have sustained maxillofacial trauma.

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