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Lumbar Spine Trauma. Presented by M.A. Kaeser, DC Spring 2009. Compression Fractures. M/C fracture of the lumbar spine Result from combined flexion and axial compression M/C level is T12-L1
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Lumbar Spine Trauma Presented by M.A. Kaeser, DC Spring 2009
Compression Fractures • M/C fracture of the lumbar spine • Result from combined flexion and axial compression • M/C level is T12-L1 • Degree of compression and comminution depends on severity fo the force appliied and the strength of the vertebra • Children – torus type fracture • Incidence increases with age
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Osteoporosis and Compression Fractures • Precipitates spontaneous compression fractures during everyday activities • Classified as insufficiency fractures (“grandma fracture”) • Most commonly occur in women • Up to 35% in female pts. Over the age of 45 years may be the result of early menopause and 30% to secondary osteopenia (corticosteroids 15%, hyperthyroidism 8%, malignancy >2%)
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Symptoms/Treatment • Acute symptoms of only 10-14 days duration, if no dislocation • Treatment is based on the nature of the collapse and whether or not there is associated neurological symptomology
Stability • Post-fracture stability is determined based on the classification by Denis • Anterior column – from ALL to the mid vertebral body • Middle column – from the mid vertebral body to the PLL • Posterior column – from the PLL to the supraspinous ligament If two or more compartments are disrupted the fracture complex is unstable – neurological injury is high and interventional surgery is likely
Radiographic Signs of Vertebral Compression Fracture • Lateral radiographs best demonstrate fracture features • Include: • Step defect • Wedge deformity • Linear zone of condensation • Displaced endplate • Paraspinal hematoma • Abdominal ileus
The Step Defect • Anterior aspect of the vertebral body is under the greatest stress, the first bony injury to occur is a buckling of the anterior cortex, usually near the superior vertebral endplate • Seen as a sharp step off of the anterosuperior vertebral margin along the smooth concave edge of the vertebral body • As the superior endplate is compressed in flexion, a sliding forward of the vertebral endplate occurs
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Wedge Deformity • Anterior depression of the vertebral body occurs, creating a triangular wedge shape • The posterior vertebral height remains uncompromised, differentiating a traumatic fracture from a pathologic fracture • May create angular kyphosis in the adjacent area • Superior endplate is far more often involved than the inferior endplate • 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.cascadewellness clinic.com/GRAPHICS/ 2ARTGFX/00ARTGFX/ COMPFRAC.GIF
Linear White Band of Condensation (Zone of Impaction) • Band of raadiopacity may be seen just below the vertebral endplate that has been fractured • The band represents the early site of bone impaction following a forceful flexion injury where the bones are driven together • Callus formation adds to the density of the radiopaque band later, in the healing stage of the fracture injury • Band is not always apparent • If present, denotes a fracture of recent origin (<2 months’ duration)
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Disruption in the Vertebral Endplate • A sharp disruption in the fractured vertebral endplate may be seen • May be difficult to perceive on plain films and tomography • CT provides the definitive means of identification • The edges of the disruption are often jagged and irregular • Superior is more commonly fractured
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Paraspinal Edema • With extensive trauma, U/L or B/L paraspinal masses may occur – these represent hemorrhage • Best seen in the thracic spine on the AP projection • In L/S edema creates asymmetrical densities or bulges in the psoas margins
http://download.imaging.consult.com/ic/images/ S1933033207730938/gr3-midi.jpg
Abdominal Ileus • An excessive amount of small or large bowel has in a slightly distended lumen • Occurs as a result of disturbance to the visceral autonomic nerves or ganglia from pain, paraspinal soft tissue injury, edema or hematoma • This sign warns that the trauma was severe and fracture is likely
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Old vs New Compression Fracture • Signs of a fracture <2 months old = soft tissue hemorrhage, step defect and white band of condensation • Healing of compression fracture can take up to 3 months in the adult spine • Presence of contiguous disc degeneration is common in old compression fractures owing to altered discovertebral mechanics • MRI reveals bone marrow edema with recent fracture • Bone scan shows increased uptake with recent fractures undergoing repair (they may remain active for up to 18-24 months after injury, which diminishes its usefulness)
Burst Fractures • Specific form of a compression fracture • Posterosuperior fragment is displaced into the spinal canal • Neurological injury may result in up to 50% of cases (best demonstrated by MRI or CT) • Most burst fractures are stable and can be treated adequately with conservative measures • AP film – a vertical fracture line is often seen, • 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
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Posterior Apophyseal Ring Fractures • Separation of the posterior vertebral body ring apophysis (posterior limbus bone) is a relatively uncommon abnormality • More common in adolescents and young adults • Clinical features include stiffness and spasm, numbness, weakness, neurogenic claudication and occasionally cauda equina syndrome • Most common levels are L4/5 and L5/S1 • 50% are caused by trauma (ie. weightlifting, MVAs, gymnastics) • Surgery may be warranted • Between 15% and 20% are visible on lateral radiographs • CT is definitive method of diagnosis
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Kummel’s Disease • Delayed post-traumatic vertebral collapse • Occurs months after an episode of spinal trauma • Caused by complicating avascular necrosis resulting in progressive compression deformity • Intravertebral vacuum phenomenon may be evident on radiographs
http://download.imaging. consult.com/ic/images/ S1933033206702300/gr10- midi.jpg
Fractures of the Neural Arch • TP fractures – 2nd M/C fracture of the L/S • Occur from avulsion of the paraspinal muscles, usually secondary to a severe hyperextension and lateral flexion blow to the L/S • Large forces are usually involved • M/C segments are L2/3 • Frequently missed on initial examination • Usually occurring close to its point of origin from the vertebra • Frequently displaced inferiorly • If the fracture is horizontal, check for transverse or Chance fracture • Fractures often occur at multiple levels • Fractures of the L5 TP are frequently found in association with pelvic fractures • Loss of the psoas shadow may occur secondary to hemorrhage • Always check for abdominal organ injuries • Associated renal damage may be associated with hematuria • CT exam is recommended to check for fracture and integrity of the abdominal contents
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Pars Interarticularis Fractures • True fractures, not stress fractures, are uncommon • MOI – violent hyperextension of the L/S – usually at the L4 or L5 level • Not to be confused with spondylolysis of the pars, which is usually the result of a stress fracture • Acute fractures are U/L, spondylolysis is B/L • Acute fractures heal without residual defects or anterior displacement
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Chance or Lap Seat Belt Fracture • Horizontal splitting of the spine and neural arch • Use of lap-type seat belts in the ’50s and ’60s coincided with an increasing occurrence of Chance fractures • Severe abrasions can be seen on the lower anterior abdominal wall, outlining the position of the seat belt • Internal visceral damage may occur – rupture of the spleen or pancreas and tears of the small bowel and mesentery • Neurological deficits in 15% of cases • M/C location is upper L/S (L1-L3)
http://www.ajronline.org/cgi/content- nw/full/183/4/959/FIG6 http://www.e-radiography.net/radpath/f/chance%20fracture/ Chance-sagital_recon.jpg
Fracture-Dislocation • M/C in the T/L area afer a vilent flexion injury • Avulsion fractures (teardrop) are commonly found associated with dislocation of the L/S • Most dislocations are anterior in position, without lateral displacement • Shearing injuries with disc and ligament rupture and fractures of the posterior arch are common • Naked facet sign – absence of apposed articular facets – diagnostic for facet dislocation
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References Yokum TR, Rowe LJ. Essentials of Skeletal Radiology. Baltimore: Williams & Wilkins, 1996: 373–545.