This chapter addresses traumatic fractures and dislocations to the thoracolumbar (TL) spinal column. These injuries are uncommon, and when present, are frequently overlooked. This is likely due to the fact that other more significant injuries in the traumatized patient distract the clinician and because signs and symptoms of the vertebral injury are often subtle.1 Early diagnosis and treatment of these injuries improves neurologic outcome.2
In victims of blunt trauma receiving thoracic and/or lumbar spine radiographs, approximately 6% will have a fracture.3 The absence of back tenderness does not exclude a TL fracture, however, as 40% of patients with a fracture won't have pain or tenderness.4,5 Radiographs are recommended in the setting of high-energy trauma (fall > 10 ft, high speed motor vehicle collision) and one of the following4–8:
Back pain or midline back tenderness
Abnormal neurologic examination
Any other spine fracture
Glasgow Coma Scale < 15
Major distracting injury9
Alcohol or drug intoxication
Computed tomography (CT) scan is frequently indicated as it is more sensitive than plain films for detecting fractures.10 Multi-detector CT of the abdomen and chest with reconstructions of the spine is as accurate for detecting TL spine fractures as dedicated spinal CT.11 This technique also saves time and cost.12
Fractures of the TL spine are most common at the junction of the rigidly fixed thoracic spine and the flexible lumbar spine. Approximately 50% of all fractures of the TL region occur between T11 and L3.3 Fortunately, because the spinal canal is wider in this location than the cervical spine, complete cord lesions are less common.
In considering the stability of TL vertebral fractures, the three-column classification is conceptually the easiest to understand. In this system, developed by Denis, the spinal column is divided into three sections: anterior, middle, and posterior13,14 (Fig. 10–1). The anterior column consists of the anterior longitudinal ligament and the anterior half of the vertebral bodies and disks. The middle column is made up of the posterior longitudinal ligament and the posterior half of the vertebral bodies and disks. Lastly, the posterior column consists of the supraspinous and interspinous ligaments and facet joints. Mechanical stability is present if two of the three columns are intact.
The three-column classification of the thoracolumbar spine.
Multiple mechanisms of injury have been described that produce somewhat predictable TL vertebral fractures. They include flexion, flexion-rotation, extension, compression, distraction, and shear (i.e., translational) forces. In the system developed by McAfee, three major forces (axial compression, axial distraction, and translational) act on the middle column to create five different injury patterns: wedge compression fracture, burst fracture, Chance fracture, flexion-distraction injuries, and translational injuries.15–17 These five injury patterns are considered mechanically unstable and are discussed below, followed by a discussion of mechanically stable TL fractures.
No one classification system will include all injury patterns and in difficult cases, the injury should be considered unstable until imaging and expert opinion suggest otherwise.18
Wedge Compression Fractures
This is the most common fracture in the thoracic and lumbar spine. These fractures are due to flexion and distraction, causing failure of the anterior column of the spine (Fig. 10–2). Because the middle and posterior columns remain intact, this is a stable injury without risk of causing spinal cord injury. It is classified here with unstable fractures because other mechanically unstable injuries (i.e., burst fractures) may mimic the wedge compression fracture.10
An anterior wedge compression fracture is a stable fracture because it involves only the anterior column.
In awake patients, pain and tenderness are present at the site of the fracture, most commonly the midthoracic or upper lumbar region. The injury may occur after any type of trauma but is especially common in patients with osteoporosis, who may sustain a wedge compression fracture after an injury as trivial as a sneeze. They are also associated with the muscle contraction that comes with an epileptic seizure and have been reported in patients riding in vehicles that have gone over a speed bump.19,20 Neurologic injury is not associated with this fracture because the middle and posterior columns of the spine remain intact.
This fracture is best seen on the lateral radiograph, where the vertebral body takes on a wedge shape (Fig. 10–3). The vertebral body is compressed anteriorly and the posterior cortex of the vertebral body is normal. CT scan is recommended whenever the integrity of the posterior vertebral body and posterior column structures are questionable, as plain radiographs do not adequately evaluate the posterior vertebral body cortex.21 The patient should be considered to have an unstable fracture until it is clear that the anterior vertebral body is all that is involved.
Anterior wedge compression fracture of T12.
The treatment of a simple wedge compression fracture is pain relief and early mobilization with increasing activity as the pain subsides. Physical therapy may be appropriate and activity is rarely restricted by 3 to 4 months following the injury.
Long-term instability of the spine can occur with severe compression fractures (> 50% loss of the body height) or when multiple adjacent wedge fractures are present.
A burst fracture is a comminuted fracture of the vertebral body due to axial compression (Fig. 10–4). It is an unstable fracture because the anterior and middle ...