SUMMARY Thoracolumbar Burst Fractures are a common high-energy traumatic vertebral fractures caused by flexion of the spine that leads to a compression force through the anterior and middle column of the vertebrae leading to retropulsion of bone into the spinal canal and compression of the neural elements. Diagnosis is made with radiographs of the thoracolumbar spine. CT scan is useful for fracture characterization and surgical planning. Treatment is bracing or surgical decompression and stabilization depending on whether the patient has neurologic deficits and whether the facture is unstable with a risk of drifting into kyphosis. Epidemiology Demographics often seen from falls from height or motor cycle accidents ETIOLOGY Pathophysiology mechanism axial loading with flexion pathoanatomy at thoracolumbar junction there is fulcrum of increased motion that makes spine more vulnerable to traumatic injury burst fractures typically occur between T10-L2 (thoracolumbar junction) neurologic deficits canal compromise often caused by retropulsion of bone maximum canal occlusion and neural compression at moment of impact tissue recoiling post-injury can minimize the extent of displacement retropulsed fragments resorb over time and usually do not cause progressive neurologic deterioration deficit type location of stenosis relative to conus determines spinal cord injury conus medullaris syndrome neurogenic claudication due to stenosis distal to conus Associated injuries concomitant spine fractures occurs in 20% traumatic durotomy associated with lamina fractures split spinous process chest and intra-abdominal injuries common thoracic spine fractures with neurologic deficit 1/3 associated with hemopneumothorax, major vessel injury, and diaphragmatic rupture flexion-distration and fracture-dislocations bowel rupture, major vessel injury, upper urinary tract injury, hepatic, splenic, and pancreatic lacerations long bone fractures can make rehabilitation difficult ANATOMY Thoracic osteology T1-10 are rigidly fixed to ribs that join each other anteriorly via the sternum least mobile portion of the entire spine T10-L2 is considered the thoracolumbar junction T10-12 have free floating ribs and are more mobile than the upper thoracic spine transition from rigid thoracic spine to mobile lumbar spine acts as a stress riser and predisposes to injury Lumbar osteology increasingly more mobile as progresses caudal increasingly prone to degenerative changes Denis three column system clinical relevance only moderately reliable in determining clinical degree of stability definitions anterior column anterior longitudinal ligament (ALL) anterior 2/3 of vertebral body and annulus middle column posterior longitudinal ligament (PLL) posterior 1/3 of vertebral body and annulus posterior column pedicles lamina facets ligamentum flavum spinous process posterior ligament complex (PLC) instability defined by injury to middle column as evidenced by widening of interpedicular distance on AP radiograph loss of height of posterior cortex of vertebral body disruption of posterior ligament complex combined with anterior and middle column involvement Posterior Ligamentous Complex considered to be a critical predictor of spinal fracture stability consists of supraspinous ligament interspinous ligament ligamentum flavum facet capsule evaluation determining the integrity of the PLC can be challenging conditions where PLC is clearly ruptured bony chance fracture widening of interspinous distance progressive kyphosis with nonoperative treatment facet diastasis conditions where integrity of PLC is indeterminant MRI shows signal intensity between spinous process Spinal cord spinal cord ends at L1-2 conus medullaris houses upper motor neurons on the sacral motor nerves fractures involving L1 and result in conus medullaris syndrome paralysis of the bowel and bladder with sparring of the motor nerve roots of the lower extremity CLASSIFICATION Dennis classification Type A fracture of both end-plates. The bone is retropulsed into the canal. Type B fracture of the superior end-plate. It is common and occurs due to a combination of axial load with flexion. Type C fracture of the inferior end-plate. Type D Burst rotation. This fracture could be misdiagnosed as a fracture-dislocation. The mechanism of this injury is a combination of axial load and rotation. Type E Burst lateral flexion. This type of fracture differs from the lateral compression fracture in that it presents an increase of the interpediculate distance on anteroposterior roentgenogram Thoracolumbar Injury Classification and Severity Score injury characteristic qualifier points injury morphology compression (+1 point) burst (+2 points) rotation/translation (+3 points) distraction (+4 points) neurologic status intact (0 point) nerve root (+2 points) incomplete Spinal cord or conus medullaris injury (+3 points) complete Spinal cord or conus medullaris injury (+2 points) cauda equina syndrome (+3 points) posterior ligamentous complex integrity intact (0 point) no interspinous ligament widening seen with flexion views. MRI shows no edema in interspinous ligament region suspected/indeterminate (+2 points) MRI shows some signal in region of interspinous ligaments disrupted (+3 points) widening of interspinous distance seen TLICS treatment implications score < 4 points nonsurgical management score = 4 points nonsurgical or surgical managment score > 4 points surgical management indicated PRESENTATION History high-energy mechanism axial-loading and flexion mechanisms fall from height (e.g. fall from deer hunting stand, fall from ladder, etc.) high-speed motor vehicle collision Symptoms severe back pain radicular pain parasthesias Physical exam vital signs hypotension is common neurogenic shock hypotension with associated bradycardia suggests spinal cord injury leading to loss of autonomic regulation hypovolemic shock hypotension with compensatory tachycardia suggests massive hemorrhage from major vessel injury inspection log roll patient during initial assessment to avoid iatrogenic spinal cord injury in the setting of an unstable fracture pattern skin abraisons and ecchymosis open spinal fractures are uncommon palpation of spinous processes fluid collection crepitus increased interspinous distance suggests injury to the posterior elements localized tenderness neurologic examination motor sensory reflexes absence of bulbocavernous reflex is considered spinal shock can persist for up to 72 hours hyperactive bulbocavernous reflex suggests disinhibition and a complete spinal cord injury IMAGING Radiographs recommended views AP/lateral cervical, thoracic, lumbar spine often CT chest, abdomen, and pelvis done by trauma team and instead of radiographs imaging of entire spine must be performed due to concomitant spine fractures in 20% flexion and extension lateral radiographs useful once patient is stabilized to get understanding of integrity of PLC findings AP shows widening of pedicles coronal deformity lateral shows retropulsion of bone into canal extent of retropulsion can be underestimated with plain radiographs alone kyphotic deformity chance-like spinous process fx flexion/extension diastasis of spinous process with flexion indicates soft tissue injury to PLC CT scan indications fracture on plain film neurologic deficit in lower extremity inadequate plain films higher sensitivity at detecting acute spine fractures than plain films most accurately assesses the extent of fragment retropulsion best assess on the axial views better assessment vertebral body comminution CT myelography indications alternative for patients with pacemaker and other implants that are MRI incompatible cannot assess the cord status consider traumatic durotomy MRI indications whenever neurological deficits assess the presence of a posterior ligamentous injury should be performed in nearly every case, unless radiographs and CT clearly suggest injury useful to evaluate for level of conus relative to retropulsed bone spinal cord or thecal sac compression by disk or osseous material cord edema or hematoma cord edema fusiform cord enlargement increased signal intensity on T2-weighted images cord hematoma decreased singal intensity on T2-weighted images halo of T2 enhancement for surrounding edema presence of cord edema more than 2 vertebral levels and hematoma are poor prognostic signs for functional motor recovery injury posterior ligament complex increased signal intensity on T2 weighted images in PLC is concerning for instability and may warrant surgical intervention best visualized on the sagittal images TREATMENT Nonoperative activity as tolerated +/- thoracolumbosacral orthosis indications patients that are neurologically intact and mechanically stable posterior ligament complex preserved no focal kyphosis on flexion and extension lateral radiographs kyphosis < 30° (controversial) vertebral body has lost < 50% of body height (controversial) TLICS score = 3 or lower modality thoracolumbar orthosis recent evidence shows no clear advantage of TLSO on outcomes if it provides symptomatic relief, may be beneficial for patient bracing may not be suitable for those with associated abdominal or chest injuries outcomes retropulsed fragments resorb over time and usually do not cause neurologic deterioration decreased complication rates in neurologically intact patients treated nonsurgically equivalent outcomes in neurologically intact patients prolonged bedrest associated with increased deconditioning and recumbency complications (pneumonia, DVT, etc.) Operative posterior instrumented fusion/stabilization without decompression indications unstable fracture pattern as defined by injury to the Posterior Ligament Complex (PLC) progressive kyphosis lamina fractures (controversial) polytrauma surgical stabilization can assist with recovery and rehabilitation of other injuries technique may be performed with percutanous pedicle screws using fluoroscopy or navigation may extend instrumentation further than level of arthrodesis (fuse short, instrument long) outcomes unstable injuries are more likely to benefit from surgical stabilization compared to nonsurgical treatment neurologic decompression & spinal stabilization indications neurologic deficits with radiographic evidence of cord/thecal sac compression both complete and incomplete spinal cord injuries require decompression and stabilization to facilitate rehabilitation TLICS score = 5 or higher techniques while classic teaching was anterior approach is required to eliminate anterior pathology, with modern techniques decompression can be performed with posterior approach favored when below conus so possible to medialize thecal sac to perform decompression of canal / posterior corpectomy and expandable cage injury to posterior ligamentous complex so posterior tension-band stabilization required fracture dislocations anterior/direct lateral approach favored when neurologic deficits caused by anterior compression (bony retropulsion) , especially above the conus medullaris (above L2) allow for thorough decompression of the thecal sac substantial vertebral body comminution in order to reconstitute the anterior column kyphotic deformity >30° chronic injuries greater than 4-5 days from the injury cons must consider level of diaphragm outcomes studies have suggested posterior distraction instrumentation with ligamentotaxis have similar clinical and radiographic outcomes as anterior decompression and 360° stabilization over distraction of the anterior column can lead to pseudoarthrosis, chronic pain, and recurrent deformity TECHNIQUES Posterior instrumented fusion/stabilization without decompression approach posterior midline approach subperiosteal elevation of paraspinal musculature expose lateral to the transverse processes technique transpedicular screw fixation above and below the level of injury historically involve three levels above and two levels below the level of injury modern constructs typically involve one level above and one level below the injury short segment fixation not suitable for injuires involving the thoracolumbar junction complications loss of sagittal plane correction Neurologic decompression & spine stabilization approach posterior approach typically posterior midline approach subperiosteal elevation of paraspinal musculature expose lateral to the transverse processes anterior approach lumbar spine anterior retroperitoneal or transperitoneal approach left paramedian incision suitable for levels below L1 thoracolumbar junction lateral lumbotomy suitable for injuries at T11-L1 left-sided approach to avoid liver obstructing access thoracic spine lateral thoracotomy right-sided approach to avoid major vessels appropriate for injuries above T11 technique neural decompression direct decompression posterior decompression retropulsed bone can be removed via transpedicular approach usually done below the level of the conus medullaris (L2) significant dural retraction required, which may iatrogenically damage the cord avoid laminectomy if possible as it will further destabilize the spine by compromising the posterior supporting structures anterior decompression corpectomy performed with direct removal of canal-occupying fragments ipsilateral pedicle and transverse process are removed corpectomy performed until the medial wall of the contralateral pedicle is visualized preferrable for fractures at or above the level of the conus medullaris (L1-2) indirect decompression distraction and lordosing rod construct leads to ligamentotaxis of the retropulsed fragments attachements of the annulus fibrosis and posterior longitudinal ligament to the fragments facilitates reduction less effective if performed 4-5 days after the injury restored height and sagittal alignment with posterior instrumentation monoaxial screws provided greater distractive forces for deformity correction arthrodesis posterior fusion usually performed with locally harvested autograft and freeze-dried cancellous allograft +/- BMP posterior instrumentation should be under distraction and lordosis to restore vertebral body height and achieve indirect decompression anterior fusion structural bone graft placed in corpectomy site to reconstitute the anterior column tricortical iliac crest autograft humeral or tibial allograft expandable metal cages with locally harvested autograft can be stabilized with anterior instrumentation, posterior instrumentation, or both complications posterior decompression dural tear iatrogenic cord injury excessive thecal retraction above the conus medullaris iatrogenic instability laminectomy in the setting of disrupted posterior ligamentous complex anterior decompression ileus transperitoneal approach to the lumbar spine pleural effusion related to approaches requiring thoractomy COMPLICATIONS Entrapped nerve roots and dural tear from associated lamina fractures can be iatrogenic from decompression decreased risk of dural tears with anterior approach due to improved visualization of the thecal sac during decompression requires closure primarily or reinforced with dural patch prolonged recumbency postoperatively Pain most common over distraction with instrumentation Progressive kyphosis common with unrecognized injury to PLL increased comminution of the vertebral body loss of anterior column support Flat back leads to pain, a forward flexed posture, and easy fatigue post-traumatic syringomyelia Surgical site infection can occur in up to 10% of cases trauma predisposes to infection catabolic state increased soft tissue damage inflammatory response requires irrigation and debridement with culture specific antibiotics Pseudoarthrosis can result from overdistraction instrumentation Iatrogenic neurologic injury can occur in 1% of cases causes include over medialized pedicle screws inadvertant manipulation of the spinal cord