Thoracic and Lumbar Trauma
Thoracic Compression Fracture
• M.C. at T11 and T12
• Hematoma may cause displacement of the
paraspinal stripe on AP film
• Wedge shape vertebra on lateral film
http://download.imaging.consult.com/ic/images/S1933033207730938/
gr3-midi.jpg
http://orthoinfo.aaos.org/topic.cfm?topic=A00538
Thoracic Fracture-Dislocation
• M.C. T4-T7
• Often associated with neurological damage
because canal is small and blood supply is sparse
• Rad features include loss of
vert. body height, displacement,
widened interpediculate
distance and widened paraspinal
stripe
*Best appreciated on CT
http://www.ajronline.org/cgi/content-nw/full/187/4/859/FIG12
Lumbar compression Fractures
• M.C. fxs. of L/S; L1 is m.c.
• In elderly, due to osteoporosis (insufficiency fx)
• Stability is determined based on Denis’ 3-column model
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–
–
–
Anterior- from ALL to mid-vertebral body
Middle- from mid-vert. body to PLL
Posterior- from PLL to supraspinous lig.
Disruption of 2 or 3 columns implies instability
• Likelihood of neurological injury is high and
interventional surgery is likely necessary
http://www.radiologyassistant.nl/en/4906c8352d8d2
http://www.nrmedical.net/nrpd-xrayreporting.asp
Rad. Signs of Vert. Compression Fxs.
• Step defect- buckling of the anterior cortex, near the superior
vertebral endplate on lateral view
• Wedge deformity- anterior depression of the vertebral body
occurs, creating a triangular wedge shape
– Up to 30% or greater loss in anterior height may be required before the deformity
is readily apparent on convention x-rays
– Normal variant anterior wedging of 10-15% or 1-3 mm is common thought the T/S
and most marked at T11-L2
http://www.ski-injury.com/specific-injuries/spinal1
Rad. Signs of Vert. Compression Fxs.
• Zone of Condensation- band of radiopacity below sup. Endplate
represents the early site of bone impaction following a forceful
flexion injury where the bones are driven together
– If present, denotes a fracture of recent origin (<2 months’ duration)
• Paraspinal edema- U/L or B/L hemmorrhage may occur
– Displaces paraspinal stripe on AP T/S; creates asymmetrical densities or
bulges in psoas margins on AP L/S
http://www.dynamicchiropractic.com/mpacms/dc/article.php?id=51049
http://download.imaging.consult.com/ic/images/
S1933033207730938/gr3-midi.jpg
Rad. Signs of Vert. Compression Fxs.
• Abdominal ileus- seen radiographically as excessive
amount of small or large bowel has in a slightly
distended lumen
• Warns that the trauma was severe and fracture is likely
• Results from disturbance to the
visceral autonomic nerves or
ganglia from pain, paraspinal
soft tissue injury, edema or
hematoma
http://www.ganfyd.org/images/thumb/6/69/Axr_ileus.jpg/
180px-Axr_ileus.jpg
Old Vs. New Compression Fracture
• Previously mentioned signs disappear with
healing, which could be up to 3 months in adult
• DJD develops due to altered mechanics
• MRI reveals bone marrow edema with recent
fracture up to 6 weeks post
trauma
http://www.dynamicchiropractic.com/mpacms/dc/article.php?id=51049
Burst Fractures
• Compression fracture where posterosuperior fragment is displaced into the
spinal canal
• Neurological injury in up to 50% of cases (best demonstrated by MRI or CT)
• AP film shows vertical fracture line, which differentiates from simple wedge
comp. fx.
• Widening of the interpediculate distance signifies a fracture within the neural
arch
• Acquired coronal cleft vertebra – coronally
oriented fracture the separates the
vertebral body into anterior and posterior
halves
• Central depression of the superior and
inferior endplates occurs with
comminution of the vertebral body
http://radiopaedia.org/images/11020
Burst Fractures
http://www.medscape.com/content/2004/00/48/20/482043/482043_fig.html
Posterior Apophyseal Ring Fractures
• Separation of the posterior vertebral body ring apophysis
(posterior limbus bone) is a relatively uncommon abnormality
• Most common levels are L4/5 and L5/S1
• 50% are caused by trauma, such as weightlifting, MVAs,
gymnastics
• Between 15% and 20% are visible on lateral radiographs, but CT is
definitive
• Surgery may be warranted after failure of conservative care and in
the presence of significant
neurological compromise
http://www.sciencedirect.com/science/article/pii/S089970711200037X
Kummel’s Disease
• Post- traumatic vertebral collapse, caused by rarefying
process in vert. body months after trauma
• Results from complicating avascular necrosis resulting
in progressive compression
deformity
• Intravertebral vacuum
phenomenon may be evident
on radiographs
http://radiopaedia.org/cases/kummell-avn?fullscreen=true
Fractures of the Neural Arch
• Transverse process fractures- 2nd m.c. L/S fx.
– Occur from avulsion of the paraspinal muscles, usually secondary to a
severe hyperextension and lateral flexion blow to the L/S
– M.C. at L2 and L3
– Loss of the psoas shadow may occur secondary to hemorrhage
– Large forces involved, so organs may be damaged as well
• Pars interarticularis fractures- acute fxs
(not stress fxs.) are rare
– Violent hyperextension of L/S, usually at L4 or L5
– Usually unilateral, not bilateral like stress fx.
– Heal without residual defects or anterior
displacement
http://www.sciencedirect.com/science/
article/pii/S1529943011014033
http://openi.nlm.nih.gov/detailedresult.php?img=2776377_JETS-02-217g001&query=the&fields=all&favor=none&it=none&sub=none&uniq=0&sp=none&re
q=4&simCollection=2762171_IJO-43-234-g001&npos=36&prt=3
Chance or Lap Seat Belt Fracture
•
•
•
•
•
Aka fulcrum fracture; seat belt acts as fulcrum over abdomen
Horizontal splitting of the spine and neural arch
Internal visceral damage may occur – rupture of the spleen or pancreas and tears of the
small bowel and mesentery
M/C location is upper L/S (L1-L3)
AP radiograph shows transverse fracture through the posterior elements and angulation
of the superior portion of the fractured vertebra
– The resulting widened radios gap between the two fractured segments has been turned empty
vertebra
•
Lateral radiographs shows radiolucent split through spinous process, lamina, pedicle and
upper corner of the posterior aspect of the vertebral body
http://www.radiologyassistant.nl/en/4906c8352d8d2
Fracture-Dislocation
• Usually at thoracolumbar junction after a violent flexion injury
• Avulsion fractures (teardrop) are commonly found associated
with dislocation of the L/S
• Most dislocations are anterior in position, without lateral
displacement
• Complete luxation with lateral shift of spine may create cord or
cauda equina paralysis
• Axial CT shows absence of
apposed articular facets
(naked facet sign)
http://www.ajronline.org/content/187/4/859/F4.expansion.html
References
• Yochum, T.R. (2005) Yochum and Rowe’s
Essentials of Skeletal Radiology, Third Edition.
Lippincott, Williams and Wilkins: Baltimore.