A thoracic burst fracture is a serious injury in which one of the vertebral bodies in the middle portion of the spine is compressed and breaks in multiple directions.
Unlike a simple compression fracture, a burst fracture can cause the vertebral body to spread outward and may push fragments of bone backward into the spinal canal. Because the thoracic spinal canal contains the spinal cord, a burst fracture can sometimes cause spinal cord compression or neurologic injury.
Thoracic burst fractures most often occur after significant trauma, but they can also develop after lower-energy injuries when the bone has been weakened by osteoporosis, cancer, or another condition.
What Is a Burst Fracture?
The vertebral body is the large, weight-bearing portion of each vertebra.
In a burst fracture, the vertebral body is subjected to a strong compressive force and breaks apart. The fracture may involve:
- The front of the vertebral body
- The middle portion of the vertebral body
- The back wall of the vertebral body
- The endplates above or below the vertebra
- The spinal canal
The back wall of the vertebral body may be pushed backward toward the spinal cord. This is called retropulsion.
Some burst fractures remain mechanically stable, while others disrupt the supporting structures of the spine and become unstable.
What Causes Thoracic Burst Fractures?
Thoracic burst fractures are usually caused by a strong force transmitted through the spine.
Common causes include:
- Falls from a height
- Motor vehicle accidents
- Motorcycle accidents
- Sports injuries
- Crush injuries
- High-energy trauma
They may also occur after lower-energy trauma in patients with:
- Osteoporosis
- Metastatic cancer
- Multiple myeloma
- Other diseases that weaken bone
The amount of force required to cause a burst fracture depends heavily on the strength of the vertebra.
Symptoms of a Thoracic Burst Fracture
Symptoms vary depending on the severity of the fracture and whether the spinal cord has been injured.
Possible symptoms include:
- Severe mid-back pain
- Pain that worsens with movement
- Muscle spasms
- Tenderness over the injured vertebra
- Difficulty standing or walking
- Numbness or tingling
- Leg weakness
- Loss of coordination
Severe spinal cord injury may result in:
- Marked weakness
- Paralysis
- Loss of sensation
- Bowel or bladder dysfunction
Some patients with burst fractures remain completely neurologically intact despite significant changes on CT or MRI.
Can a Burst Fracture Damage the Spinal Cord?
Yes.
Bone fragments from the back of the fractured vertebral body may enter the spinal canal and reduce the space available for the spinal cord.
However, the amount of narrowing seen on imaging does not always predict neurologic function.
Some patients may have substantial canal narrowing but no neurologic deficit, while others can suffer significant spinal cord injury at the time of trauma.
Neurologic examination is therefore an important part of evaluating a thoracic burst fracture.
Stable Versus Unstable Burst Fractures
One of the most important questions is whether the fracture is stable.
A stable burst fracture may maintain acceptable spinal alignment and allow treatment without surgery.
An unstable fracture may have damage to multiple structural components of the spine, making it more likely to collapse, deform, or move abnormally.
Features suggesting greater instability may include:
- Severe vertebral collapse
- Significant kyphotic deformity
- Injury to the posterior spinal ligaments
- Widening between the spinous processes
- Facet joint disruption
- Translation of one vertebra relative to another
- Progressive deformity on follow-up imaging
- Associated flexion-distraction injury
The degree of spinal canal narrowing alone does not determine whether the spine is unstable.
The Posterior Ligamentous Complex
The posterior ligamentous complex is a group of structures along the back of the spine that helps maintain stability.
It includes:
- Supraspinous ligament
- Interspinous ligament
- Ligamentum flavum
- Facet joint capsules
Damage to these structures can make a burst fracture significantly less stable.
MRI may be used when there is concern for injury to the posterior ligamentous complex.
How Are Thoracic Burst Fractures Diagnosed?
Evaluation typically includes a neurologic examination and several types of imaging.
X-rays
X-rays may show:
- Loss of vertebral height
- Widening of the vertebral body
- Kyphotic deformity
- Abnormal spinal alignment
However, CT is generally much better for defining the fracture pattern.
CT Scan
CT is one of the most important studies for evaluating a burst fracture.
It can demonstrate:
- The extent of vertebral body disruption
- Retropulsed bone fragments
- Spinal canal narrowing
- Posterior element fractures
- Facet injuries
- Spinal alignment
CT also helps determine whether the injury is a simple compression fracture, burst fracture, Chance fracture, or a more complex fracture-dislocation.
MRI
MRI may be particularly useful when there is:
- Neurologic injury
- Concern for spinal cord compression
- Suspicion of ligament injury
- Concern for disc injury
- Uncertainty about spinal stability
MRI can also show swelling, bruising, or injury within the spinal cord itself.
Neurologically Intact Burst Fractures
Many patients with thoracic or thoracolumbar burst fractures have normal strength and sensation.
In these patients, surgery is not automatically required simply because CT demonstrates some retropulsion into the spinal canal.
Treatment depends on:
- Mechanical stability
- Spinal alignment
- Degree of vertebral collapse
- Integrity of the posterior ligaments
- Pain
- Overall health
- Ability to mobilize safely
Stable fractures with acceptable alignment can often be treated without surgery.
Nonsurgical Treatment
Nonsurgical treatment may be appropriate for selected patients with stable burst fractures and no neurologic deficit.
Treatment may include:
- Pain medication
- Early mobilization
- Activity restrictions
- Physical therapy
- Bracing in selected patients
- Follow-up X-rays
The goal is to allow the fracture to heal while maintaining acceptable alignment.
Prolonged bed rest is generally avoided whenever possible because it can lead to:
- Muscle loss
- Blood clots
- Lung complications
- Deconditioning
- Loss of independence
Bracing
A thoracolumbosacral orthosis, or TLSO brace, may sometimes be used.
A brace can:
- Reduce painful movement
- Provide support
- Help patients feel more secure while walking
Not every stable burst fracture requires bracing.
Whether a brace is used depends on fracture location, alignment, pain, and physician preference.
When Is Surgery Recommended?
Surgery is more likely to be recommended when there is:
- Progressive neurologic deficit
- Significant spinal instability
- Major ligament disruption
- Progressive kyphotic deformity
- Severe vertebral collapse
- Fracture-dislocation
- Inability to mobilize because of pain
- Progressive loss of alignment during nonsurgical treatment
Surgery may also be necessary when spinal cord compression is associated with neurologic deterioration.
Goals of Surgery
The goals of surgery are to:
- Stabilize the injured spine
- Maintain or restore spinal alignment
- Prevent additional deformity
- Protect the spinal cord
- Decompress the spinal cord when necessary
- Allow earlier mobilization
Not every patient requires direct removal of retropulsed bone.
In some cases, restoring spinal alignment and stabilizing the spine may indirectly improve the dimensions of the spinal canal.
Posterior Pedicle Screw Instrumentation
One of the most common surgical treatments for a thoracic burst fracture is posterior pedicle screw instrumentation.
Screws are placed into vertebrae above and below the fracture and connected with rods.
This construct can:
- Stabilize the injured vertebra
- Restore alignment
- Reduce kyphosis
- Protect the spine while healing occurs
A spinal fusion may be performed at the same time depending on the type of injury and surgical goals.
Spinal Decompression
A decompression may be required if the spinal cord remains significantly compressed.
Possible procedures include:
- Laminectomy
- Removal of retropulsed bone
- Transpedicular decompression
- Costotransversectomy
- Corpectomy
The specific approach depends on where the compression is located.
A laminectomy alone does not directly remove bone fragments located in front of the spinal cord and may sometimes worsen instability if performed without appropriate stabilization.
Corpectomy and Vertebral Reconstruction
A corpectomy involves removing most or all of the damaged vertebral body.
This may be necessary in severe burst fractures when:
- The vertebral body is extensively destroyed
- There is severe anterior spinal cord compression
- The front portion of the spine cannot adequately support weight
- Significant deformity requires reconstruction
After the vertebral body is removed, the space may be reconstructed with:
- An expandable cage
- Structural graft
- Other vertebral body replacement devices
Posterior screws and rods are commonly used to provide additional stability.
Short-Segment Versus Long-Segment Fixation
The number of vertebrae included in a surgical construct depends on:
- Location of the fracture
- Severity of instability
- Bone quality
- Degree of deformity
- Associated injuries
Some fractures can be treated with relatively short instrumentation around the fracture.
More severe thoracic injuries may require fixation across several levels.
Because the thoracic spine is naturally less mobile than the lumbar spine, longer constructs may be better tolerated in some thoracic injuries.
Burst Fractures in Patients With Osteoporosis
Burst fractures can be more difficult to treat when the bone is severely osteoporotic.
Poor bone quality can increase the risk of:
- Screw loosening
- Additional fractures
- Progressive collapse
- Junctional fractures
- Loss of surgical correction
Surgical strategies may include:
- Longer fixation constructs
- Additional fixation points
- Cement augmentation of selected screws
- Vertebral augmentation
- Medical treatment to improve bone quality
Treatment of osteoporosis is an important part of the overall plan.
Recovery After a Thoracic Burst Fracture
Recovery depends on:
- Severity of the fracture
- Presence of spinal cord injury
- Whether surgery was required
- Age
- Bone quality
- Overall health
Patients without spinal cord injury may gradually return to normal activity over several months.
Pain often improves before complete bone healing has occurred.
Physical therapy may focus on:
- Walking
- Core strength
- Posture
- Balance
- Endurance
- Gradual return to activity
Patients with spinal cord injury may require more extensive rehabilitation.
How Long Does a Burst Fracture Take to Heal?
Bone healing commonly takes approximately 8 to 12 weeks, although recovery varies.
Patients treated nonsurgically may undergo repeat X-rays to confirm that alignment remains stable during healing.
After surgical stabilization, restrictions are based on the extent of injury, the type of fixation, and the patient’s bone quality.
Full functional recovery may take several months.
Possible Complications
Complications from the fracture itself may include:
- Progressive spinal deformity
- Chronic back pain
- Neurologic deterioration
- Spinal instability
- Post-traumatic kyphosis
Possible surgical complications include:
- Infection
- Bleeding
- Dural tear
- Cerebrospinal fluid leak
- Spinal cord injury
- Hardware failure
- Nonunion
- Adjacent-level problems
The individual risk depends greatly on the severity of the original injury.
Post-Traumatic Kyphosis
A burst fracture can cause the injured vertebra to collapse and produce an abnormal forward bend in the spine.
This is called post-traumatic kyphosis.
Mild kyphosis may cause few symptoms.
More severe deformity can produce:
- Chronic mechanical back pain
- Difficulty standing upright
- Progressive imbalance
- Fatigue
- Neurologic compression in selected cases
Progressive or severe deformity may occasionally require reconstructive spinal surgery.
When Is a Thoracic Burst Fracture an Emergency?
Thoracic burst fractures usually occur after significant trauma and should be evaluated promptly.
Emergency evaluation is especially important when there is:
- New leg weakness
- Paralysis
- Numbness
- Difficulty walking
- Loss of sensation
- Bowel or bladder dysfunction
- Severe spinal deformity
- Significant trauma with severe back pain
These findings may indicate spinal cord injury or an unstable spinal fracture.
Outlook
Thoracic burst fractures range from relatively stable injuries that can heal without surgery to severe injuries associated with spinal instability and spinal cord damage.
The appearance of the fracture on a CT scan is only one part of the decision-making process.
Treatment should take into account:
- Neurologic function
- Spinal stability
- Fracture morphology
- Integrity of the posterior ligaments
- Spinal alignment
- Degree of deformity
- Bone quality
- Overall health
Stable burst fractures in neurologically intact patients can often be treated successfully without surgery.
More unstable injuries may require instrumentation, fusion, decompression, or vertebral reconstruction to restore stability and protect the spinal cord.
Related Topics
- Thoracic Compression Fracture
- Chance Fracture
- Flexion-Distraction Injury
- Thoracic Spinal Instability
- Spinal Cord Injury
- Post-Traumatic Kyphosis
- Thoracic Pedicle Screw Instrumentation
- Thoracic Spinal Fusion
- Thoracic Corpectomy