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Pediatric Cervical Spine. X-ray Rounds, Phil Ukrainetz, MD, PGY5 December 5, 2002. “Normal anatomy”. C-spine ABC’s Corresponding anatomy Pseudosubluxation Positioning. C-spine ABC’s. Alignment Bone Cartilage Soft tissue. C-spine ABC’s. C-spine ABC’s. Anatomy. Pseudosubluxation.
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Pediatric Cervical Spine X-ray Rounds, Phil Ukrainetz, MD, PGY5 December 5, 2002
“Normal anatomy” • C-spine ABC’s • Corresponding anatomy • Pseudosubluxation • Positioning
C-spine ABC’s • Alignment • Bone • Cartilage • Soft tissue
Pseudosubluxation • Physiologic anterior translation of C2 on C3 in children • Seen in 25% of children < 8 yoa • May be seen up to 16 yoa • Seen in up to 1/3 of all pediatric neck films
Why do they pseudosublux? • Horizontal facets • Weak neck musculature • Cartilage artifact • Ligamentous laxity • Increased with neck flexion
Causes of anterior translation of C2 on C3 in children • Pseudosubluxation • Hangman’s fracture
Swischuk line • Posterior cervical line • “Draw from C1 posterior arch to the cortex of the posterior cortex of C3 arch” • Line should pass through or be less than 1 mm anterior to the posterior arch of C2 • Swischuk LE. Radiology 1977; 122: 759-763
Problem’s with Swischuk Line • We see normal Swischuk line with hangman’s fractures - not sensitive or positive in disease • We see abnormal Swischuk line with normal necks in flexion - not specific or negative in health • A value >1.5 -2mm suggests an occult hangman’s fracture • Woodward GA, Neck Trauma, Fleisher/Text Ped Emerg Med, Fourth Ed. 2000, pp 1327
In Swischuk’s words.. • “The posterior cervical line should only be applied when C2 is displaced anteriorly on C3”
Positioning • Huge cranium • Exhalation • Neck spasm flexion
Summary • Swischuk line is a diagnostic adjunct • Consider pre-test probability • Consider concordance with tests • Low likelihood of injury and abnormal film - consider repositioning/disregard • High likelihood of injury and normal film - continue investigating
Unstable C-spine fractures • Jefferson (C1 burst) • Bit (Bilateral facets) • Off (Odontoid) • A (Any fracture dislocation) • Hangman’s (C2 pedicle fracture) • Tit (Flexion/Extension teardrop)