A burst fracture is a severe spinal injury that occurs when a vertebra is subjected to extreme compressive forces, causing the bone to fail in multiple directions. This compression injury is significantly more serious than a simple wedge compression fracture because the entire vertebral body shatters, or “bursts,” into several fragments. The condition threatens the spine’s stability and the integrity of the delicate nervous structures housed within.
Anatomical Description and Mechanism of Injury
A burst fracture typically occurs in the thoracolumbar region of the spine, the transitional area between the rigid thoracic (chest) spine and the more flexible lumbar (lower back) spine. This region, commonly spanning from the tenth thoracic vertebra (T10) to the second lumbar vertebra (L2), is particularly vulnerable to traumatic forces. The injury arises from a high-energy axial load, meaning a force directed vertically along the axis of the spine, such as landing on one’s feet after a fall from a height or sustaining a motor vehicle accident.
The force causes the vertebral body, the main cylindrical weight-bearing part of the bone, to collapse and fragment outward. The defining characteristic is the retropulsion of bone fragments, where pieces of the shattered bone are pushed backward into the spinal canal. This carries a high risk of neurological damage, as the spinal canal contains the spinal cord and nerve roots.
In contrast to a simple compression fracture, which only involves the front part of the vertebral body, a burst fracture involves the failure of both the anterior and middle columns of the spine’s structural support. This failure severely compromises the spine’s stability. The resulting instability and the presence of bone fragments near the spinal cord determine the overall severity.
Symptoms and Medical Identification
The immediate symptom of a burst fracture is severe, intense pain localized to the area of the back, which worsens significantly with movement. Because of the fragments pushed into the spinal canal, patients often experience neurological deficits, including numbness, tingling, and muscle weakness in the limbs. In severe instances, compression of the spinal cord may cause a loss of bowel or bladder control, which signals a neurological emergency.
The diagnostic process begins with a thorough physical and neurological examination to assess the patient’s sensation, motor function, and reflexes. Imaging studies are then ordered to confirm the fracture and determine its severity. Initial plain film X-rays confirm the presence of a fracture and show the alignment of the spine.
A Computed Tomography (CT) scan is the most effective tool for detailed bone visualization, providing cross-sectional images that clearly show the number of fragments and the extent they have entered the spinal canal. Magnetic Resonance Imaging (MRI) is used to assess soft tissue damage, which is not visible on a CT scan. The MRI reveals injury to the spinal cord itself, surrounding ligaments, and intervertebral discs, which is vital for planning treatment.
Management and Treatment Paths
The management of a burst fracture depends on two factors: the stability of the spine and whether the patient exhibits neurological deficits. Non-surgical treatment is reserved for stable fractures where the spine’s alignment is maintained, canal compromise is minimal, and there is no neurological injury. This conservative approach involves immobilizing the spine, often using a rigid brace, such as a Thoracolumbar Sacral Orthosis (TLSO), for eight to twelve weeks.
The brace limits the range of motion to promote proper fracture healing and prevent further spinal collapse. Patients are kept under close observation with follow-up X-rays to ensure the fracture does not worsen. Once the brace is removed, a physical rehabilitation program is instituted to help restore strength to the trunk and lower extremities.
Surgical intervention is indicated when the fracture is unstable, involves a high degree of angulation, or causes a neurological deficit due to significant bone retropulsion. The primary goals of surgery are to decompress the spinal cord and nerve roots by removing the bone fragments and to stabilize the injured segment. Decompression involves carefully removing the bone pressing on the neural elements, sometimes requiring an anterior approach through the chest or abdomen.
Stabilization is achieved through internal fixation, where metal instrumentation, such as rods and screws, is used to fuse the fractured vertebra to the stable vertebrae above and below it. This instrumentation holds the spine rigid while the bone heals and fuses, providing long-term support. The decision regarding surgical approach depends on the fracture pattern and the strategy for achieving both decompression and robust stabilization.