upper cervical spine - occult injury and trigger for ct exam · pdf fileupper cervical spine -...

Presentation material is for education purposes only.All rights reserved. ©2006 URMC Imaging Sciences

Upper Cervical Spine -Upper Cervical Spine - Occult Injury and Trigger Occult Injury and Trigger

for CT Examfor CT Exam

Bakman M, Chan K, Bang C,Basu A, Seo G, Monu JUV

Department of Imaging SciencesUniversity of Rochester Medical Center, Rochester, NY


IntroductionIntroduction

• Failure to recognize and diagnose injury tothe upper cervical spine on plainradiographs can lead to dramatic anddevastating consequences to the patientespecially and to the radiologist.

Continued on next slide



• CT examination of the cervical spine aidsand significantly improves diagnoses inmany instances. Unfortunately it is neithereconomically feasible nor desirable toobtain CT on all patients




• Meticulous attention to detail and zerotolerance for deviations from the usualradiographic landmarks will help selectcases that should obtain additionalimaging in form of CT or MRI scans.


Initial Factors inInitial Factors inSpinal Trauma EvaluationSpinal Trauma Evaluation

• Can a patient be cleared based on clinicalexamination.

• What plain radiographs should be taken.

• When to utilize additional modalities suchas CT or MRI.


Clinical Clearance ofClinical Clearance ofCervical Spine Injury CriteriaCervical Spine Injury Criteria

• Fully alert and oriented without mental statuschanges secondary to trauma, drugs or alcohol.

• No neck pain.

• No neurologic symptoms attributable to spineinjury (paralysis, paresis, paresthesis).

• No history of head injury or loss ofconsciousness.

• No distracting injury (e.g. fractured arm).



Clinical Clearance ofClinical Clearance ofCervical Spine Injury Criteria contCervical Spine Injury Criteria cont’’dd

• If the conditions described on precedingslide are met, cervical spine can becleared clinically.

• However, it is not always possible todetermine if there was indeed head injuryor loss of consciousness at time ofaccident due to lack of witnesses.

• Therefore radiographic evaluation isemployed.


Plain radiographsPlain radiographs

• Overall up to 20% percent of cervicalspine fractures are missed.

• Open mouth views are inadequate inunconscious patients.

• Lower C-spine frequently requires multiplerepeats to visualize the C7-T1 junction.

• Current guidelines for clearing the C-spinecan assist the inexperienced radiologist.


Radiographic EvaluationRadiographic Evaluation

• An initial cross-table lateral film of thecervical spine is obtained as part of thetrauma workup in many institutions.

This is often inadequate as cranio-cervicaland cervico-thoracic junction is poorlyvisualized and additional views arenecessary.


Standard C-Spine SeriesStandard C-Spine Series

• An evaluation of cervical spine mustinclude the following 3 views:

1. lateral view2. anteroposterior view3. odontoid view


Lateral ViewLateral View

• Base of the occiput should be visualized

• Junction of C7-T1 must be visualized

• A swimmer’s view taken with one armextended over the head can be helpful


Anteroposterior ViewAnteroposterior View

• Must include the spinous processes of allthe cervical vertebrae from C2 trough T1.


Odontoid ViewOdontoid View

• Must show relationship of the lateralmasses of C1 and the odontoid process.

• If the patient is unconscious, an adequateodontoid view is not possible and a CTscan should be obtained.


Cervical Spine SeriesCervical Spine Series

• A cervical spine series that lacks any oneof the mentioned views or that does notcover the cervico-thoracic junction isinadequate and patient must remainimmobilized until clearance can beobtained by other means such as CT.


Cervical Spines NormsCervical Spines Norms

• 10-13mmCord dimensionCord dimension

• < 11 degreesAngulation of spinal column atAngulation of spinal column atany single interspace levelany single interspace level

• < 6mm at C2• < 22mm at C6• For children 1/2 to 2/3vertebral body distanceanteroposteriorly

Retropharyngeal spaceRetropharyngeal space

• 3mm or less(4-5mm in children)

C2-C3 pseudosubluxationC2-C3 pseudosubluxation

• 3mm or less(4-5mm in children)

Predental spacePredental space


2 3

RP

RT

RP = retropharyngeal spaceRT = retrotracheal space

1 = anterior vertebral line2 = posterior vertebral line3 = spinolaminar line4 = posterior spinous line

1

4

Normal Cervical SpineNormal Cervical Spine


Lateral ViewLateral View

• Four lines should be examined:– Anterior spinal line (1)– Posterior spinal line (2)– Spinolaminar line (3)– Posterior spinous process line (4)

• Any malalignment indicates an occultfracture or ligamentous injury and shouldtrigger a CT scan.


Lateral view does not show theLateral view does not show thecervico-thoracic junctioncervico-thoracic junction

SwimmerSwimmer’’s view shows antero-s view shows antero-listhesis of C-6 on C-7 of > 3mmlisthesis of C-6 on C-7 of > 3mm

Case 1Case 1



Case 1Case 1

Images show right-sided pedicle and laminaImages show right-sided pedicle and laminafracture, facet joint separation and leftwardfracture, facet joint separation and leftwardrotation in a jumped facet.rotation in a jumped facet.



CT of thoracic spineCT of thoracic spineT4 compression fractureT4 compression fractureand spinous processand spinous processfracturefracture

MRI evaluation shows no cord injury, butMRI evaluation shows no cord injury, buttear of the anterior and posteriortear of the anterior and posteriorlongitudinal ligamentslongitudinal ligaments

Case 1Case 1


Teaching Points 1-1Teaching Points 1-1

• Must visualize through C7-T1.

• A translation of >3.5mm is significantanywhere.

• Anterior subluxation of one vertebra onanother indicates facet disruption. Lessthan 50% of the width equals unifacet andmore than 50% bilateral facet disruption.



• This case also demonstrates anothercrucial point.

• If a fracture of cervical spine is seen,complete CT evaluation of C, T, and L-spine is required to rule out additionalfractures.

• 5% of spinal injuries have a secondfracture elsewhere in the spine.



• The spinous processes are examined forevidence of interspinous space widening –“fanning”.

• Fanning indicates ligamental injury or anoccult fracture and should trigger a CTexam.


Case 2Case 2

Open mouth and lateral views showOpen mouth and lateral views showless than 3mm anterolisthesis of C4 onless than 3mm anterolisthesis of C4 onC5, likely degenerative. HoweverC5, likely degenerative. Howeverprevertebral soft tissue space isprevertebral soft tissue space is> 6mm which should trigger a> 6mm which should trigger arecommendation for a CT exam.recommendation for a CT exam.



Case 2Case 2

CT images show fracture extends into body of dens (type III )CT images show fracture extends into body of dens (type III )


Teaching Points - 2Teaching Points - 2

• The predens space should be less than3mm for adults and less than 4mm inchildren.

• Increase in prevertebral soft tissue spaceat C2 and C6 is very specific, but notsensitive.

• Increased distance should trigger a CTexam to exclude occult pathology.


Case 3Case 3

Plain film radiograph showsPlain film radiograph showsprevertebral soft tissue swellingprevertebral soft tissue swellingat C2 and C6 level and fractureat C2 and C6 level and fractureof the dens.of the dens.



Case 3Case 3

Images show malalignment of lateral masses on the left.Images show malalignment of lateral masses on the left.



Case 3Case 3

CT images show fractures of the dens and anterior arch of C1 with softCT images show fractures of the dens and anterior arch of C1 with softtissue swelling.tissue swelling.


Teaching Points - 3Teaching Points - 3

• Lateral masses of C1 should align withlateral masses of C2.

• The space on each side of dens should besymmetric.

• On an AP view cervical spines shouldalign in midline.


Case 4Case 4

Plain films which show lucent linePlain films which show lucent linerunning through body of C2 and arunning through body of C2 and avery subtle lucency through thevery subtle lucency through thepedicles/posterior elements of C2.pedicles/posterior elements of C2.



Case 4Case 4

CT images show fracture through the pedicle of C2 with extensionCT images show fracture through the pedicle of C2 with extensionto the body.to the body.


Case 5Case 5

Lateral view of the C-Lateral view of the C-spine shows lucency atspine shows lucency atthe posterior aspect ofthe posterior aspect ofthe body of C2 andthe body of C2 andindistinct posteriorindistinct posteriormargin of dens.margin of dens.Fracture of C2 wasFracture of C2 wassuspected.suspected.



Case 5Case 5

Images show fracture of left lateral mass of C2 with extension toImages show fracture of left lateral mass of C2 with extension toforamen transversarium.foramen transversarium.



Case 5Case 5

MRA showed no injury toMRA showed no injury toleft vertebral artery.left vertebral artery.


Teaching Point - 4Teaching Point - 4

• Posterior elements of C2 and body of C2can harbor tell tale signs of fractures, butcan be extremely difficult to recognize. Ifsuspected, a CT scan should be obtained.


ConclusionConclusion

• Faced with a task of clearing a cervical spine, a numberof options are available.

– The first discriminator is whether or not the patientcan be cleared clinically.

– If that is not possible, radiographic evaluation isneeded.

– Strict adherence to a minimum three view plainradiograph C-spine series must be maintained.

– Deviation from established parameters for cervicalspine radiographs should trigger a CT for additionalevaluation.


ReferencesReferences

• Clark CR, Igram CM, el-Khoury GY, et al: Radiographicevaluation of cervical spine injuries. Spine 13:742-7,1988

• el-Khoury GY, Kathol MH, Daniel WW: Imaging of acuteinjuries of the cervical spine: Value of plain radiography,CT, and MR imaging. AJR Am J Roentgenol 164:43-50,1995

• Graber MA, Kathol M. Cervical spine radiographs in thetrauma patient. American Family Physician Vol. 59/no2(January 15, 1999).

• Brohi K. Initial assessment of spinal trauma. trauma.org7:4, April 2002 [http://www.trauma.org/spine/cspine-eval.html]

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