Fractures to the thoracolumbar spine are not uncommon. Most commonly these present in the elderly population and are caused by osteoporosis. There is a separate website address in this educational series addressing osteoporotic fractures of the spine. On this site, we will talk about traumatic thoracolumbar burst fractures in the younger population. The two most common mechanisms for thoracolumbar fractures are compression injuries and flexion distraction injuries.
Compression injuries can result in a burst fracture from a fall from a significant height or an extreme axial force. These fractures take place typically in the lower cervical spine and the thoracolumbar region from T10 to L2. The T10 to L2 region is specifically susceptible due to the biomechanics of the spine and the increased stresses placed on the this region due to the termination of the true ribs at T10. The classic example of this type of injury occurs if someone falling or jumping from a multistory building.
Although the patient may land on his/her feet, they are susceptible to calcaneal/ankle fractures and thoracolumbar fractures due to the transmission of these axial forces through his/her body and into the middle and lower back. The patient typically will complain a significant back pain and may/may not have neurologic symptoms. The patient requires a full trauma evaluation for his injury. Once the ABCs of the trauma evaluation are addressed, the patient's spine is assessed. The patient's lower extremity strength, sensation, reflexes and private areas must be tested and the patient must have normal bowel/bladder function to exclude the possibility of injury to the lower spinal cord and exiting nerves.
The second type of injury that is seen at less commonly is the flexion-distraction injury. This is usually caused by a rapid deceleration of the patient during a motor vehicle accident. This force increases the stresses on the spine in the thoracolumbar region and may cause many types of fractures, including a burst fracture or a 'chance' fracture. A chance fracture is a fracture that involved the front of the spine (vertebral body) and extends into the posterior elements of the spine, thus creating a unstable region of the spine where the top of the spine and the bottom of the spine are not connected to one another. This patient may also have other injuries such as abdominal injuries and/or cardiovascular injuries that must also be monitored. Once the other organ systems have been addressed, definitive treatment of the spine fracture can take place. Until then, the patient should be either on bedrest or in a brace if permitted with close neurological observation.
Depending on the nature of the fracture and the patient's neurological symptoms, the spine surgeon must determine whether or not surgical intervention is warranted versus conservative treatment in the form of a rigid hyperextension brace. While there have been many animal and cadaveric studies performed to try to determine what factors or elements are required to maintain the stability of the spine, the simple truth is that no one really sure what defines an unstable spine in a living human being and what types of injuries would benefit from prophylactic surgical intervention. The spine is thus then most commonly assessed for stability by using the 3 column model developed by Francis Denis. Two columns are composed by the front of the spine and one column is made up of the back of the spine. If 2 or more of these columns are disrupted, then spine is considered unstable and may benefit from prophylactic surgical intervention instead of very close observation with the rigid extension brace. If the patient is neurological symptoms, surgical treatment is warranted to prevent progression of the neurological problems and to attempt to reverse the neurological injury.
The most famous clinical study was published by Kirk Wood in the year 2003. In this study, he demonstrates that - despite significant injuries to the spine that would make it unstable based on animal models and cadaveric studies, patients without neurological deficits benefited more when spine fractures were treated with conservative treatment than those treated with prophylactic surgical intervention. Again, the patients in this study had no neurological deficits and no bowel/bladder problems. As a result of the improved outcome and decreased health care costs of the patients treated conservatively, it has become common practice now to treat neurologically intact patients with rigid hyperextension braces and close observation rather than prophylactic surgical treatment.
If surgery is needed for worsening neurological deficits, progressive spinal instability/kyphosis, or unreleventing pain, surgery is recommended on the spine in the front (anteriorly) and the back (posteiorly) to provide the best spinal decompression and spinal stabilization. This can be done through a posterior only approach or an anterior/posterior approach, possibly requiring the assistance of a general surgeon. Each case is unique in that the fracture pattern, the number of levels involved, the patient's body type, and the surgeon's expertise determine the best treatment plan.
Since its situation is different and unique patient circumstances determine the surgical decision making, please discuss any specific situations or questions with a fellowship trained orthopedic spine surgeon.