Imaging of Atlanto-Occipital and Atlantoaxial Traumatic Injuries: What the Radiologist Needs to Know

Abstract

Approximately one-third of all cervical spine injuries involve the craniocervical junction (CCJ). Composed of the occiput and the first two cervical vertebrae, this important anatomic landmark, in conjunction with an intricate ligamentous complex, is essential to maintaining the stability of the cervical spine. The atlantoaxial joint is the most mobile portion of the spine, predominantly relying on the ligamentous framework for stability at that level. As acute onsite management of trauma patients continues to improve, CCJ injuries, which often lead to death onsite where the injury occurred, are increasingly being encountered in the emergency department. Understanding the anatomy of the CCJ is crucial in properly evaluating the cervical spine, allowing the radiologist to assess its stability in the trauma setting. The imaging findings of important CCJ injuries, such as atlanto-occipital dissociation, occipital condyle fractures, atlas fractures with transverse ligament rupture, atlantoaxial distraction, and traumatic rotatory subluxation, are important to recognize in the acute setting, often dictating patient management. Thin-section multidetector computed tomography with sagittal and coronal reformats is the study of choice in evaluating the extent of injury, allowing the radiologist to thoroughly evaluate the stability of the cervical spine. Furthermore, magnetic resonance (MR) imaging is increasingly being used to evaluate the spinal soft tissues and ligaments, and to identify associated spinal cord injury, if present. MR imaging is also indicated in patients whose neurologic status cannot be evaluated within 48 hours of injury. .

Skull Base–related Lesions at Routine Head CT from the Emergency Department: Pearls, Pitfalls, and Lessons Learned

“…The anatomy of the CSB is complex and compact. As previously stated, using thin-section bone algorithms and obtaining coronal or sagittal reformatted images are useful for identifying subtle skull base conditions (2). Important structures are housed in the CSB, including the pituitary gland, cavernous sinuses, and basal foramina, which contain an array of vital neurovascular structures (6)(7)(8)(9).…”

“…Atlanto-occipital dissociation results from the disruption of these ligaments, usually caused by extreme hyperextension and lateral flexion in high-velocity trauma. These injuries are often associated with severe neurologic deficits and high mortality, particularly from vascular and brainstem injuries (2,35).…”

“…greater than 5 mm. Studies have shown the superiority of depicting findings on thinly collimated spiral CT images (2). Obtaining thin-section images of 3 mm or less is recommended in the setting of trauma, as use of thick-section images has been found to miss a significant number of linear fractures and skull base lesions, particularly when the images are obtained in the horizontal plane (3,4).…”

“…In addition to obtaining directly acquired axial images, high-resolution multiplanar reformatted images, including those obtained in the coronal and sagittal planes, may be constructed from the axial dataset to increase sensitivity in the acute setting (2,5). At our trauma center, in addition to obtaining CT images with 5-mm section thickness, we routinely obtain 0.625-mm thin-section images by using a bone algorithm with sagittal and coronal reformatted images for all trauma head CT protocols, thereby enhancing the depiction of complex skull base anatomy.…”

The craniocervical junction: embryology, anatomy, biomechanics and imaging in blunt trauma

“…The incidence of spinal cord and nerve root injury as a result of hangman’s fracture is reportedly low. It is suggested that if a patient survives the initial injury, the relatively capacious canal at the level of the axis affords some protection against cord injury [73, 77, 81, 82]. The majority of these traumatic spondylolistheses can be treated with non-surgical methods such as halo immobilisation or cervical collar immobilisation.

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