Mandibular Fractures: Pearls and Pitfalls
- Jul 30th, 2018
- Sarah Brubaker
Author: Sarah Brubaker, MD (EM Resident, San Antonio, TX) // Edited by: Alex Koyfman, MD (@EMHighAK) and Brit Long, MD (@long_brit)
You work in a rural hospital with minimal resources and poor access to subspecialty services. At 2 AM, a 27-year-old male presents to your emergency department with complaints of jaw pain after being punched in the face by several assailants just prior to arrival. According to EMS report, there is substantial swelling over his left lower jaw. He does not have evidence of trauma elsewhere. Before you enter the room, you think to yourself, “What if this patient has a mandibular fracture? Are there any exam maneuvers to help me make this decision? What imaging modality should I use to confirm the diagnosis? If he has a fracture, do I need to transfer him to a higher level of care?”
Mandibular fractures are the second-most common facial fracture (after nasal fractures) , representing up to 55% of all facial and skull fractures . They are most common in 16 to 30 year-old males , and are usually caused by direct force (e.g. physical assault) and motor vehicle collisions. Mandibular fractures caused by motor vehicle collisions are often associated with other injuries and therefore confer high morbidity and mortality . However, isolated mandibular fractures may be present in cases of physical assault or other forms of isolated head trauma. While most mandibular fractures do not require emergent intervention in the emergency department, emergency clinicians play an essential role in stabilization and initial management that will ultimately determine long-term outcomes. Therefore, it is important to have a basic understanding of the evaluation, imaging, treatment, and disposition for patients with possible mandibular fractures.
Evaluation of patients with possible facial fractures begins with airway management. Mandibular fractures often cause distracting deformities, but they can also lead to substantial bleeding and/or swelling that can quickly progress to airway compromise. Anterior mandibular fractures, as well as bilateral mandibular fractures, can create significant bony instability that leads to soft tissue swelling and prolapse of oral structures , which may result in marked airway obstruction.
Having suction readily available is the first important step, as heavy bleeding is common in open fractures. Allow the patient to sit in the position most amenable to airway protection, in an attempt to avoid aspiration. Traditional physical maneuvers (e.g. jaw thrust) are less likely to be effective, and bag-valve mask ventilation may be ineffective . These problems are even more pronounced in bilateral mandibular fractures. If the fracture is severe enough to cause an obstruction, or if the patient necessitates intubation for other reasons, initiating your “difficult airway” algorithm is paramount. Use video laryngoscopy, if available. Have a backup plan if this fails, which may include the use of a bougie and other adjuncts (fiberoptics). Have materials ready for cricothyrotomy, in case your first attempts fail.
Detailed physical exam
Once you have secured the airway, or if the patient’s airway is intact, do not become so distracted by a facial fracture that you forget to assess for evidence of trauma elsewhere. Complete your primary and secondary surveys as you would for any other trauma patient. Then, try to perform a more focused assessment of the mandible.
Keep in mind that the mandibular body is the most common site of fracture [7, 8], followed by the angle and condyle. Symphysis and ramus fractures also occur but are much less likely.
Visually inspect and palpate
Fractures can be subtle, indicated only by slight swelling or focal tenderness. Evaluate for asymmetry, deformity, and external swelling. Have the patient open his mouth, then both look and palpate for missing teeth, misaligned dentition, palpable fractures, lacerations, and bleeding. Palpate the sublingual space, as a sublingual hematoma may be the only exam finding to suggest an otherwise occult mandibular fracture.
The mandible is u-shaped, so bilateral fractures are common, cited by several sources as being present in greater than 50% of all mandibular fractures [6, 9, 10]. Therefore, if you find one fracture, look for a second. In addition, due to transmission of forces across the structure, the fracture may be present on the side opposite to the point of impact. Lastly, the muscles of mastication are very powerful and can worsen the displacement of a fracture, but they can also mask a fracture by naturally reducing it.
Check nerve function
Perform a quick sensory exam of the jaw. Mandibular fractures often damage the inferior alveolar nerve, which results in unilateral paresthesia to the lower lip and chin.
Test for malocclusion
Next, ask the patient to bite down. Ask him/her, “Do you feel like your teeth are coming together normally?” Subjective malocclusion (as reported by the patient) has been found to be significantly more sensitive than a clinician’s subjective impression .
The most useful exam maneuver is the “tongue-blade test,” which has sensitivity of 95% and specificity of up to 68% [12, 13], with a negative predictive value of 95% . Have the patient bite down on a wooden tongue depressor. Twist the blade while attempting to pull it out of the patient’s mouth. A fracture is unlikely if the patient is able to break the tongue depressor.
Look for evidence of open fracture
It is very important to search for any evidence of open wounds. Keep in mind that a small gum laceration near the mandibular fracture may represent an open fracture.
Current evidence suggests that patients with normal occlusion (verified by a normal tongue-blade test) and no evidence of open fracture rarely require further evaluation or treatment . However, if you have concern for mandibular fracture after your physical exam, then proceed to confirmatory imaging.
Traditional mandibular series x-rays have a sensitivity of 74% and specificity of 78% , so they are not sufficient to effectively evaluate for mandibular fracture. Because panoramic x-ray, in combination with an AP film, have a sensitivity of 92% and specificity of 97%, they are often cited as the first-line imaging modality [16, 17].
However, panoramic imaging is not available at many facilities, and a follow-up CT is recommended if the X-ray fails to demonstrate a fracture in the setting of high clinical suspicion. In addition, maxillofacial CT scans are 100% sensitive in detecting mandibular fractures [18, 19], so they are the definitive imaging modality and are generally the initial imaging modality of choice.
Unfortunately, there are no well-accepted decision-making rules to help avoid over-imaging patients with mandibular trauma. In the Manchester Mandibular Fracture Decision Rule (2005), the absence of five exam findings (malocclusion, trismus, broken teeth, pain with closed mouth, and step deformity) was said to exclude mandibular fracture ; the rule was 100% sensitive and 39% specific in detecting mandibular fractures. The authors of the study posited that the decision rule would decrease the need for imaging by 31%. However, mandibular fractures were diagnosed with AP/lateral x-rays, which is not the gold-standard imaging modality. In addition, the study was never validated. Therefore, at this time, all patients with suspected mandibular fractures should receive further imaging.
The goal of emergency department care is to stabilize the patient until they are able to follow-up with a specialist . Most patients with mandibular fractures do not require follow-up for 2-3 days. However, do not minimize your role: prompt and appropriate treatment can prevent debilitating long-term consequences, such as infection and permanent deformity. There are a few basic concerns to address before deciding whether to discharge or admit your patients:
Constantly assess airway stability
Reassess the airway multiple times during a patient’s ED visit. The patient will need to be admitted if they display signs of impeding airway compromise, such as drooling, inability to tolerate oral intake, stridor, subjective difficulty breathing, or significant intraoral swelling .
Look for missing teeth
If you cannot account for all missing teeth, obtain a chest x-ray to evaluate for aspiration .
Like any other fracture, mandibular fractures are very painful. If attempts to obtain adequate analgesia fail, the patient will need to be admitted for pain control. Patients will also require pain control for home if discharged.
Use of prophylactic antibiotics for mandibular fractures is a controversial topic. Several studies demonstrate a marked reduction in the rate of post-operative infection for patients who are given prophylactic antibiotics before open fixation of mandibular fractures . In one study, the rate of infection was decreased from 62% (for patients without antibiotics) to 29% (for patients with antibiotics). However, because the quality of literature is poor and the results are inconsistent [23, 24], there is a wide range of practice patterns. Some specialists consider all mandibular fractures to be “open” due to the mandible’s proximity to oral flora . Others only offer antibiotics to patients with truly open fractures, compound fractures , or fractures of the dentoalveolar ridge. Most sources agree that antibiotics are not needed for condylar fractures .
Because the topic is so controversial, strongly consider prophylactic antibiotics in any patient with a mandibular fracture. All open fractures require antibiotics. Gingival lacerations should always be treated as open fractures, if they are located near the vicinity of a mandibular fracture.
Penicillins, cephalosporins, and clindamycin are all reasonable antibiotic choices, because they are effective against strep and other oral flora. There are no formal recommendations to guide this decision. Two of the best-studied antibiotics are Penicillin VK (500 mg twice daily for seven days), Amoxicillin/clavulanic acid (875/125 mg twice daily for seven days), or clindamycin (600 mg four times day for seven days) for patients who are penicillin-allergic .
It is recommended to offer a tetanus vaccination if the patient has not received immunization within the last five years .
Splint and bandage
Tooth avulsions: If the patient has an avulsed tooth, it is well within the scope of an emergency provider’s practice to replace and temporarily splint the tooth. Store the tooth in milk or Hank’s solution. Cleanse the tooth with warm water, but do not scrub the root or use antibacterial solution, as the nerves and soft tissues should remain as intact as possible . Replace the tooth into the alveolar socket. Use a wire, prepackaged periodontal dressing, or calcium hydroxide paste to place the teeth in proper alignment [21, 27]. Patients with avulsed teeth need to follow-up with a specialist within 24 hours for more definitive care. These patients require urgent evaluation but can be discharged if you are confident they can access a maxillofacial specialist within 24 hours.
Displaced fractures: Grossly displaced fractures that cause airway obstruction require immediate attention by a specialist, but the others can be splinted in the ED prior to outpatient follow-up (use the same techniques as for tooth avulsions). If there are actively mobile segments, splinting is of utmost importance, as these fractures can lead to airway compromise and permanent deformities if not rapidly addressed.
Minimally-displaced and nondisplaced fractures: These patients may be placed in a “Barton’s bandage” for comfort (see picture) for comfort, but do not require formal splinting.
Speak with the appropriate consultant
All patients with mandibular fractures will ultimately require evaluation by a maxillofacial specialist. Which specialty evaluates facial trauma varies depending on where you work. Follow the protocol for your hospital to contact the appropriate specialist, who will help you make the appropriate disposition for the patient. Important pieces of information to convey to the consultant include: location, displacement (including amount and direction), number of fragments, and whether the fracture is open .
The consultant should play an active role in determining the disposition of patients with mandibular fractures. However, most patients are likely safe to be discharged with outpatient follow-up. Of those who are discharged, select patients require follow-up within 24 hours. The others can establish follow-up within 48-72 hours after the time of injury [6, 21]. Here are the general guidelines for how to decide the appropriate disposition:
Admission: Poor pain control, current or impending airway compromise, unable to tolerate PO intake, (most) open fractures, unsafe social situation.
24-hour follow-up: Avulsed teeth, grossly displaced fractures, fractures with mobile segments.
48-72 hour follow-up: Most patients who do not meet the above criteria are safe for follow-up in 48-72 hours. Instruct the patients to adhere to a liquid diet until follow-up with a specialist. Prescribe oral pain medications and antibiotics (if the fracture is open). Stress the importance of follow-up and provide them with strict return precautions.
-Mandibular fractures can lead to significant bleeding and/or swelling that can result in airway compromise. Have suction and advanced airway equipment easily accessible.
-Physical exam findings can be subtle, so perform a detailed exam if the mechanism suggests possible mandibular fracture (most common mechanism is assault, followed by MVC).
-Most sensitive exam maneuver: tongue-blade test (95% sensitive).
–Maxillofacial CT is generally the first-line imaging modality.
-Search diligently for evidence of open fracture, and have a low threshold to treat with antibiotics. Some recommend treating all mandibular fractures with prophylactic antibiotics.
–Most patients with mandibular fractures can be discharged with follow-up in 48-72 hours. Arrange 24 hour follow-up for patients with tooth avulsions or grossly displaced fractures. Admit patients for pain control, airway management, or inability to tolerate PO intake.
–Involve a consultant in determining the disposition for all patients with facial fractures.
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