SUMMARY Thoracolumbar burst fractures are common high-energy traumatic vertebral fractures caused by flexion of the spine, resulting in 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 varies from bracing to surgical decompression and stabilization depending on whether the patient has neurologic deficits or if the fracture being unstable with a risk of progressing into kyphosis Epidemiology Demographics often seen after falls from height or motorcycle accidents ETIOLOGY Pathophysiology mechanism axial loading with flexion pathoanatomy the thoracolumbar junction acts as a fulcrum for increased motion, making this area of the 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 the conus Associated injuries concomitant spine fractures occur 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/or diaphragmatic rupture flexion-distraction and fracture-dislocations associated with bowel rupture, major vessel injury, upper urinary tract injury, hepatic, splenic, and/or pancreatic lacerations long bone fractures can make rehabilitation difficult ANATOMY Thoracic osteology T1-10 are rigidly fixed to ribs that join 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 this region to injury Lumbar osteology increasingly more mobile with caudal progression 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 laminae facets ligamentum flavum spinous process posterior ligament complex (PLC) instability defined by injury to middle column 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 in which the PLC is clearly ruptured: bony Chance fracture widening of interspinous distance progressive kyphosis with nonoperative treatment facet diastasis conditions where integrity of PLC is indeterminate: MRI shows signal intensity between spinous processes Spinal cord spinal cord ends at L1-2 conus medullaris contains upper motor neurons of the sacral motor nerves fractures that involve L1 can result in conus medullaris syndrome presents as bowel and bladder paralysis while the motor nerve roots of the lower extremity are spared CLASSIFICATION Denis classification type A fracture of both endplates the bone is retropulsed into the canal type B fracture of the superior endplate common and occurs due to a combination of axial load with flexion type C fracture of the inferior endplate type D burst rotation, the mechanism of this injury is a combination of axial load and rotation this fracture type can be mistaken as a fracture-dislocation type E burst lateral flexion this type of fracture differs from the lateral compression fracture in that it presents an increase in the interpedicular distance on anteroposterior radiograph Thoracolumbar Injury Classification and Severity Score (TLICS) injury characteristic qualifier points injury morphology compression (+1 point) burst (+2 points) rotation/translation (+3 points) distraction (+4 points) neurologic status intact (0 points) 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 points) 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 scoring system designed to guide decision-making in patients with thoracolumbar spine injuries points based on three categories: fracture morphology posterior ligamentous complex integrity neurologic status score <4 points nonsurgical management score =4 points nonsurgical or surgical management 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 or ladder) high-speed motor vehicle collision Symptoms severe back pain radicular pain paresthesias 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 logroll patient during initial assessment to avoid iatrogenic spinal cord injury in the setting of an unstable fracture pattern skin abrasions 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 suggests spinal shock after an acute injury can persist for up to 72 hours hyperactive bulbocavernous reflex suggests disinhibition and a complete spinal cord injury IMAGING Radiographs recommended views AP/lateral of the cervical, thoracic, and lumbar spine often replaced by CT chest, abdomen, and pelvis performed by trauma team 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 evaluate PLC integrity findings AP widening of pedicles coronal deformity lateral retropulsion of bone into canal extent of retropulsion can be underestimated with plain radiographs alone kyphotic deformity Chance-like spinous process fracture flexion/extension diastasis of spinous process with flexion indicates PLC soft tissue injury CT scan indications fracture on plain films neurologic deficit in lower extremity inadequate plain-film evaluation CT has higher sensitivity at detecting acute spine fractures than plain films most accurately assesses the extent of fragment retropulsion best assessed on the axial views better assessment of vertebral body comminution CT myelography indications alternative for patients with MRI incompatible implants (e.g. pacemaker) cannot assess the cord status consider traumatic durotomy MRI indications neurologic deficits on examination assess for a posterior ligamentous injury should be performed in nearly every case, unless radiographs/CT clearly suggest injury useful to evaluate for: level of conus relative to retropulsed bone spinal cord or thecal sac compression by disc or osseous material cord edema or hematoma cord edema fusiform cord enlargement increased signal intensity on T2-weighted images cord hematoma decreased signal intensity on T2-weighted images halo of T2 enhancement for surrounding edema presence of cord edema at more than 2 vertebral levels and hematoma are poor prognostic signs for functional motor recovery injury of posterior ligament complex increased signal intensity in PLC on T2-weighted images 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 ≤3 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 deconditioning and recumbency complications (pneumonia, DVT, etc.) Operative posterior instrumented fusion/stabilization without decompression indications unstable fracture pattern as defined by injury to the PLC progressive kyphosis laminar fractures (controversial) polytrauma surgical stabilization can assist with recovery and rehabilitation of other injuries technique may be performed with percutaneous pedicle screws using fluoroscopy or navigation instrumentation may need to extend beyond the fusion levels ('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 of 5 or higher techniques while classic teaching described that the anterior approach is required to eliminate anterior pathology, modern decompression techniques can be performed with several of the following approaches: posterior approach favored when below the conus medullaris, where the thecal sac can be safely mobilized medially and decompression of canal, posterior corpectomy, and expandable cage implantation can be performed injury to PLC so posterior tension-band stabilization can be performed fracture dislocations anterior/direct lateral approach favored when neurologic deficits that are caused by anterior compression (bony retropulsion), especially above the conus medullaris (above L2) allows for thorough decompression of the thecal sac substantial vertebral body comminution (able to reconstitute the anterior column) kyphotic deformity >30° chronic injuries >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 overdistraction of the anterior column can lead to pseudarthrosis, 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 involves 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 injuries 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 preferable for fractures at or above the level of the conus medullaris (L1-2) indirect decompression distraction and lordotic rod construct leads to ligamentotaxis of the retropulsed fragments attachments of the annulus fibrosus 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 provide 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 placed under distraction and lordosis to restore vertebral body height and alignment, achieving 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 thoracotomy 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 primary closure or reinforcement with dural patch prolonged recumbency postoperatively Pain most common can be due to overdistraction with instrumentation Progressive kyphosis common with unrecognized PLL injury increased comminution of the vertebral body loss of anterior column support Flat-back deformity leads to pain, a forward flexed posture, and easy fatigue can be due to 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, followed by culture-specific antibiotics Pseudarthrosis can result from overdistraction due to instrumentation Iatrogenic neurologic injury can occur in 1% of cases causes include over-medialized pedicle screws inadvertent manipulation of the spinal cord