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Transcript of Imaging of Cervical Spine Trauma - Amazon Web …h24-files.s3.amazonaws.com › 110213 ›...
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Imaging of Cervical Spine Trauma
C Craig Blackmore, MD, MPHProfessor of Radiology and Adjunct Professor of Health Services
University of Washington, Harborview Medical Center
Salary support: AHRQ grant 1K08 HS11291NHTSA Crash Injury Research Engineering Network
Objective• Introduce evidence-based imaging approach
– Role of CT– Who?, How?, Why?
• Injury patterns in upper C-Spine– Craniocervical junction
• Injury patterns in lower C-SpineLower– Biomechanical stability
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Who?• Clinical criteria exclude
injury– NEXUS– Canadian C Spine Rule
• Sensitivity ~100%– Specificity lower
• Awake, alert, not intoxicated
• No distracting injury• No focal pain/tenderness
over spinous processes• No neurological deficits• Normal head turning
How?
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Cervical Spine RadiographyHigh Risk Patients
• Difficult to perform– Backboards– Other injuries– Non-cooperative
• Time consuming– 10 minutes to 1 hour
• Often inadequate or incomplete
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Balance Radiography vs. CT
Radiography CT Screen• Sensitivity 94% 99%• Specificity 78-89% 93%• Time +++ +• Cost + +++
Based on critical literature review 3/2004
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Cost-Effectiveness• CT cost-effective if fracture risk>4%• Why?
– Frequency of inadequate radiographs– Extreme cost of missed fracture
• small percentage develop paralysis– Higher cost of radiography in high-risk
Blackmore, et al, Radiology 1999;212:117-125Blackmore, et al, Radiology 2001;220:581-588
Validated High Risk Criteria• Focal neurological deficit• Severe head injury
– unconscious, skull fracture, intracranial hemorrhage
• High energy mechanism– MVC speed> 35mph– auto vs. pedestrian– death at scene– pelvic fracture
• LogisticalHanson, et al, AJR 2000:174:713-718
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Special Populations
• Elderly• Children• Head injured
Location of Fractures
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C0 C1 C2 C3 C4 C5 C6 C7
1991-2003
KF Linnau, report in progress
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Elderly Subjects with Cervical Spine Fractures
From Lomoschitz, AJR 2002, 178, 573-577
Elderly• Same risk factors
– Other injuries– High energy mechanism
• Fall from standing common– 11% of fractures – harder to predict
• Type 2 dens fracturesBub, RSNA 2003Lomoschitz, AJR, 178: 573-577
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Elderly
• Same prediction rule• Low threshold for CT
– Focal pain/tenderness– Limited exam– Findings on radiography
• Focus evaluation on C2
Location of Fractures
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C0 C1 C2 C3 C4 C5 C6 C7
1991-2003
KF Linnau, report in progress
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Cervical Spine Injuries in Children
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5
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
C3-C7C0-C2
AGE
#
Adapted from Kuhns
HMC Pediatric Protocol• Under 4 years
– AP and lateral radiographs– C0-C2 on head CT
• 4-8 years– AP, lateral, open mouth, (swimmers)
• 9 and over=adult• Attending (surgeon/ER/radiol.) required for CT
under 9– Unless fracture identified
BLACKMORE CSPINE 5/05
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Radiation Reduction• Limit to high risk patients • No children
– Higher radiosensitivity– Lower fracture probability
• Lowest mAs– Neck/shoulders
Unconscious
• Head Injury– Normal cervical spine CT– Clinically unexaminable
• Further imaging?– Eastern Association for Surgery of Trauma– Ligamentous injury– MRI, Flouroscopic flexion/extension, upright
• ? Necessary
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Conclusions
• CT is accurate, rapid, effective c-spine screening strategy
• CT c-spine screening is cost-effective in high risk trauma patients
• Radiography optimal for low-risk, or if rapid CT not available
Cervical Spine Imaging Recommendations
• Sigtuna Consensus Conference• November 2005• Different scenarios• www.nordictraumarad.com
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Objective• Introduce evidence-based imaging approach
– Role of CT– Who?, How?, Why?
• Injury patterns in upper C-Spine– Craniocervical junction
• Injury patterns in lower C-SpineLower– Biomechanical stability
Upper Cervical Spine
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Craniocervical Junction
• Complex anatomy• Difficult to visualize with radiography• CT screening
– Increase injury detection– Higher sensitivity– Uncertain significance of some injuries
Injuries at CT versus XRay
1.1, 9.43.2Facet Fracture (only)
1.6, 9.13.8C6-C7 SpinousProcess (only)
3.0, 52.012.5C3-C6 Transverse Process (only)
1.3, 3.52.1Occipital Condyle95% CIOdds RatioInjury
Linnau et al, RSNA, 2004
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Missed Fractures
• Resident misses – Found by attending– At or below national averages (1.0%)– 128 cases
• Attending misses– Harder to quantify
Bittles and Ghoradia, Report in progress
Missed Fractures-Cervical Spine
• Upper cervical spine 43%– Occipital condyle 26%– Dens fractures 17%
• Lower cervical spine 57%– Posterior column 47%– Lamina/pedicle/articular mass/transverse process
Bittles and Ghoradia, Report in progress
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How NOT to Miss Fractures
• Occipital condyles• Dens• Posterior elements lower c-spine
How NOT to Miss Fractures
• Occipital condyles– 5% of fractures– Most commonly missed
• Dens– elderly
• Posterior elements lower c-spine
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Basion
Dens
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Apical
Tectorial Membrane
Cruciate
CRUCIATE
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APICAL
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ALARALAR
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Occipital Condyle Fractures
• Type 1: Burst fractures• Type 2: Extension from occiput• Type 3: Avulsion• Stability related to ligaments• Assess atlanto-occipital joint
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Left Right
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C1 Ring Fractures
• Frequency: 2-10%• Neurologic sequellae < 30%• Mechanism
–Axial load–Axial load with lateral flexion (coupling)
C1 Ring Fractures - Classification
• Jefferson (Burst)– “Stable” = no transverse ligament injury– “Unstable” = transverse ligament injury
•≥ 7 mm displacement C1 lateral masses
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TRANSVERSE
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Dens Fractures
Type IType II
Type III
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Type 1 Dens Fracture
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Type 2 Dens Fracture
• Common• Delayed & non-unions• Elderly (20%)
– Osteopenia– Diagnostic challenge– CT limitation
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Type III Dens fractures
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Hyperextension Teardrop
• Avulsion of ALL– Ant-inf corner of C2
• Stable– alignment
• DDX: Dislocation of C2-C3 disk and annulus fibrosis
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C2: “Hanged-man” Fracture• Frequency: 5-25%• Myelopathy: < 25%• Canal enlarged
–Unless body fragment
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Objective• Introduce evidence-based imaging approach
– Role of CT– Who?, How?, Why?
• Injury patterns in upper C-Spine– Craniocervical junction
• Injury patterns in lower C-SpineLower– Biomechanical stability
Lower Cervical Spine
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Biomechanical Stability
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Biomechanical Stability• “Loss of ability of the spine under
physiological loads to maintain relationships” without cord or nerve root damage or irritation
White and Punjabi, 1990
Biomechanical Stability
• Anterior and posterior columns– All plus one
• Instability: 3.5mm or 11 degrees• No universal classification
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Lower Cervical Spine
• Isolated minor fractures• Vertebral body injuries• Facet injuries• Fracture dislocations
Lower Cervical Spine
• Isolated minor fractures– Spinous process– Transverse process– Lamina
• Vertebral body injuries• Facet injuries• Fracture dislocation
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Lower Cervical Spine
• Isolated minor fractures• Vertebral body injuries
– Hyperextension teardrop– Anterior compression– Burst fracture– Flexion distraction
• Facet injuries• Fracture dislocation
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Hyperextension Teardrop
Anterior Compression Injury
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Burst Fracture
Flexion Distraction Injury(Flexion Teardrop)
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Lower Cervical Spine
• Isolated minor fractures• Vertebral body injuries• Facet injuries
– Facet fractures (with normal alignment)– Lateral mass fracture– Unilateral facet dislocation– Bilateral facet dislocation
• Fracture dislocation
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Articular Facets
Isolated Facet Fracture
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Facet Fracture with Displacement(Nerve Root Compression)
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Lateral Mass Fracture
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Lower Cervical Spine
• Isolated minor fractures• Vertebral body injuries• Facet injuries
– Facet fractures (with normal alignment)– Lateral mass fracture– Unilateral facet dislocation– Bilateral facet dislocation
• Fracture dislocation
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Unilateral Facet Dislocation
Facet Fracture/Dislocation
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Bilateral FacetDislocation
Lower Cervical Spine
• Isolated minor fractures• Vertebral body injuries• Facet injuries• Fracture dislocation
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Fracture Dislocation
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Lower Cervical Spine
• Isolated minor fractures• Vertebral body injuries• Facet injuries• Fracture dislocation
Objective• Introduce evidence-based imaging approach
– Role of CT– Who?, How?, Why?
• Injury patterns in upper C-Spine– Craniocervical junction
• Injury patterns in lower C-SpineLower– Biomechanical stability
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Photo by Ken F. Linnau
Thank You!!!!!