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As the Neuroradiologist in the emergency department, you will see a ton

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of cervical spine CT scans. In some cases, it may get you frustrated

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because in a lot of cases the patients don't have any symptoms and

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yet they're getting a cervical spine CT scan. Why is that?

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Well, in some instances, the clinicians are following algorithms based on

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the patient's level of consciousness and their age that lead to the ordering

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of cervical spine CTs, even in the face of the patient being relatively

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asymptomatic. Sometimes it's that the patient arrives from the

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scene of the car accident in a cervical spine collar and the

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clinicians, the people in the emergency room, feel compelled to

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scan the cervical spine before they remove that cervical spine collar that

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was put on, on a precautionary basis by EMS.

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Sometimes you have patients that are unconscious and we don't know what

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their symptoms are, whether they're having neck pain, and that's why the

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CT scan is performed. Sometimes it's due to falls and based on the

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mechanism of the fall, there is a higher rate of potential injury to

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the cervical spine, even in those patients who are not complaining of neck

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pain. So unconscious patient's clearance of the neck to go to the OR,

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sometimes the patients are being evaluated for fractures of the

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extremities and they have been unconscious for the period of time that they've

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been in the emergency room, so clearance of the neck to go to

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the OR to be intubated for their remediation of their abdominal injuries

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or pelvic injuries or extremity injuries. We also see the rare case of

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hanging in those individuals with suicide ideation. And another scenario

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is gunshot wound to the neck, this is particularly popular in the

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neighborhood around Johns Hopkins in East Baltimore. Most people separate

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the cervical spine into different biomechanical units. From the skull base

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to C2, we usually think about the craniovertebral junction with the atlas

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and the dens, C1 and C2. Then we have the C2 to C3 to C7 to T1 area

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of the subaxial cervical spine, and then we go into the thoracolumbar spine

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and the sacrum. Within these cervical spine, we have different names of

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some of these fractures. We have the fractures of the occipital condyle,

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usually avulsion fractures. We have Atlanto Odontoid dislocation. We have

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Atlantoaxial rotatory subluxation. These are under the craniovertebral junction

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injuries. Then we have injuries to the C1 and C2

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vertebrae themselves, which include the Jefferson C1 burst fracture, the

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odontoid fracture, and then the fracture of the

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transverse processes of the C2 vertebra, the hangman fracture.

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Within the subaxial cervical spine from C3 through C7, we usually talk about

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the mechanism of injury, which includes hyperflexion, hyperextension, and

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rotational injuries. And you may have combinations of these, particularly

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in a patient who's been in a motor vehicle accident where you initially

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have some... If they're hit from behind, you may have a initial hyperflexion,

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then the cascading backwards into hyperextension injury. Let's talk for

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a moment about occipital condyle fractures. As I mentioned, usually these

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are avulsion from the ligamentous process that's going to the odontoid process,

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and which pulls off a portion of the occipital condyle. These avulsion fractures

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are the most benign of them. However, you may have other fractures which

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are a little bit more dangerous to the patient, and sometimes you'll even

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have fractures that will lead to unstable findings. So this is the Anderson

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Montesano classification, Type 1 with the small avulsion, Type 2 more gross

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avulsion, then Type 3 with some area of rotational injury. Here you can

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see this on the CT scan and the MRI scan. Unfortunately,

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these fractures may be associated, as you can see, with ligamentous injury,

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that can also lead to instability. In this case, we have a bilateral occipital

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condyle fracture. When we're looking at the craniocervical junction or craniovertebral

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junction, we should be aware of the ligamentous complex that is associated

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with the C1, C2 and clivus. I'm gonna point out some of the

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most important ones, which include the apical odontoid ligament leading

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from the inferior border of the clivus to the top of the odontoid process.

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Then we have the tectorial membrane, the tectorial membrane is the continuation

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of the posterior longitudinal ligament to the clivus. This is this tissue

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right here. You have the transverse ligament, which goes from the lateral

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arches of C1 across the back of the odontoid process, and that is

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another very strong ligament that we very rarely will see any evidence of

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avulsion or injury to that ligament. Then there are lots of posterior ligaments,

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posterior atlanto occipital ligament, and then you have your interspinous

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ligaments, the posterior Atlantoaxial ligament, and then additional interspinous

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ligaments going all the way down. But the ones that are the most

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important are these apical odontoid ligament and the tectorial membrane

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of the posterior longitudinal ligament extension, so look for these.

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The other thing that is a concept that we talk about with all

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cervical spine injuries is to make sure that there is normal alignment of

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the various borders to the vertebral body. So this is the

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line of the anterior border of the vertebral bodies that should be smooth

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and show no offset of any vertebral body. This is the line along

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the posterior margin of the vertebral body that we also look at.

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And then we look at what's so called spinal lamina line, which goes

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at the junction between the spinous process and the lamina, and those all

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should be smooth without offset at any level, and you can see these

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lines depicted here. And finally, the blue line, the spinous process line,

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the posterior spinous line, which also is smooth without offset from anterior

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to posterior.