Thoracic and Lumbar Trauma Thoracic Compression Fracture M

Thoracic and Lumbar Trauma

Thoracic Compression Fracture • M. C. at T 11 and T 12 • Hematoma may cause displacement of the paraspinal stripe on AP film • Wedge shape vertebra on lateral film http: //download. imaging. consult. com/ic/images/S 1933033207730938/ gr 3 -midi. jpg http: //orthoinfo. aaos. org/topic. cfm? topic=A 00538

Thoracic Fracture-Dislocation • M. C. T 4 -T 7 • 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/FIG 12

Lumbar compression Fractures • M. C. fxs. of L/S; L 1 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. radiologyassistant. nl/en/4906 c 8352 d 8 d 2 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 T 11 -L 2 http: //www. ski-injury. com/specific-injuries/spinal 1

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/ S 1933033207730938/gr 3 -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/ 180 px-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_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 L 4/5 and L 5/S 1 • 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/S 089970711200037 X

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- 2 nd 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 L 2 and L 3 – 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 L 4 or L 5 – Usually unilateral, not bilateral like stress fx. – Heal without residual defects or anterior displacement http: //www. sciencedirect. com/science/ article/pii/S 1529943011014033 http: //openi. nlm. nih. gov/detailedresult. php? img=2776377_JETS-02 -217 g 001&query=the&fields=all&favor=none&it=none&sub=none&uniq=0&sp=none&re q=4&sim. Collection=2762171_IJO-43 -234 -g 001&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 (L 1 -L 3) 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/4906 c 8352 d 8 d 2

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/F 4. expansion. html

References • Yochum, T. R. (2005) Yochum and Rowe’s Essentials of Skeletal Radiology, Third Edition. Lippincott, Williams and Wilkins: Baltimore.