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 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.nrmedical.net/nrpd-xrayreporting.asp http://www.radiologyassistant.nl/en/4906c8352d8d2

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://download.imaging.consult.com/ic/images/ S1933033207730938/gr3-midi.jpg http://www.dynamicchiropractic.com/mpacms/dc/article.php?id=51049

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://openi.nlm.nih.gov/detailedresult.php?img=2776377_JETS-02-217-g001&query=the&fields=all&favor=none&it=none&sub=none&uniq=0&sp=none&req=4&simCollection=2762171_IJO-43-234-g001&npos=36&prt=3 http://www.sciencedirect.com/science/ article/pii/S1529943011014033

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.