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Emergency Radiology

E2545. Temporomandibular Joint Fracture: What the Surgeon Needs to Know

Jindal T,  Yablon C,  Morag Y,  Brigido M. University of Michigan, Ann Arbor, MI

Address correspondence to T. Jindal (tjindal@med.umich.edu)

Background Information: Traumatic injury to the temporomandibular joint (TMJ) is a morbid injury that can lead to long- term consequences if not accurately diagnosed, characterized, and treated. Long- term consequences such as chronic pain, jaw immobility, and malocclusion can lead to degraded quality of life in patients who are not adequately treated. Fractures to the condylar process of the mandible account for up to 25% of all mandibular fractures, and the decision to pursue surgical versus conservative management depends on multiple factors that can be assessed radiologically. Accurate and prompt description of these findings depends on the radiologist being familiar with normal TMJ anatomy as well as common mechanisms of injury and repair.

Educational Goals/Teaching Points: The goal of this exhibit is to review common imaging modalities used to evaluate the TMJ in the acute setting and review normal osseous anatomy as well as basic biomechanics of the TMJ. We also describe common classification patterns for TMJ fracture and review case examples. Lastly, we describe common surgical and conservative management of TMJ fracture.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: Due to widespread availability and low cost, radiography and CT are the primary methods of assessing TMJ disorders in the acute setting, and imaging is often the first-line tool in assessing TMJ trauma. The most common traumatic injuries identified are dislocations of the condylar head and mandibular condyle fractures. Initial assessment of TMJ injury is commonly done with radiography, which delineates the presence or absence of a condylar dislocation or fracture. CT allows precise localization and description of TMJ trauma including extent of fracture displacement and angulation. The five key factors that influence a surgeon’s decision making when assessing a patient with TMJ trauma include location of the fracture, unilateral versus bilateral injury, degree of fracture displacement, degree of angulation, and degree of condylar height loss. All of these factors influence a surgeon’s decision to pursue a closed versus open surgical procedure. Delay in diagnosis or mischaracterization of an injury that leads to inadequate treatment can have lifelong consequences for patients including fracture nonunion, malocclusion, chronic ankyloses, and condylar resorption in severe cases.

Conclusion: TMJ trauma is an increasingly common abnormality seen in emergency radiology settings that can carry high morbidity and long-term consequences for patients. Rapid diagnosis and proper characterization of TMJ injuries are essential to aid surgeons in guiding appropriate treatment.