Authors: Henry Greenslade / Editor: Liz Herrieven / Codes: / Published: 06/08/2024
Poor old lumbar spine it does a lot of the heavy lifting for the body but probably doesnt get anywhere near the attention of the cervical spine when it comes to trauma. However, the lumbar vertebrae are the most commonly injured vertebrae, with this region involved in 42% of all spinal injuries.1 Although seen less often than with higher spinal injuries, spinal cord injury still occurs in almost 24% of patients with lumbar involvement.
When to suspect
To compare back to the C-spine, which has established decision rules such as NEXUS, there is no current validated decision rule to help us in deciding whether to image the lumbar spine in trauma. NICE guidance2 gives a list of risk factors for thoraco-lumbar injury, included in the table below. For example, using a lap belt (or wearing the shoulder strap of a 3-point seat belt under the arm rather than over the shoulder) in a car accident is associated with risk, because of flexion of the lumbar spine which can cause a Chance fracture. Clinical examination alone is not sensitive enough to detect lumbar fractures, potentially missing 1 in 5 fractures in one study.3,4 So although tenderness and pain may raise our suspicion, we cannot always be reassured if these are missing, particularly if the mechanism or the patient is high risk. It is not surprising that the the above study3 indicates that increasing age (>60 years), and high-risk mechanism increase the risk of lumbar spine injury. Above all then, it is about maintaining a high level of suspicion, particularly in our elderly patients. If we find any of these factors described below NICE recommend full spine immobilisation pending investigation.
| NICE Guidance risk factors for thoracolumbar trauma2 |
| Age 65 or older and reporting pain |
| Dangerous mechanism (fall >3m, axial loading e.g. landing on buttocks/falling on feet, high speed motor vehicle collision, pedestrian vs. car, lap belt only, bicycle collision, horse riding) |
| Pre-existing spinal pathology (including osteoporosis) |
| Suspected spine fracture in other regions e.g. cervical/upper thoracic |
| Neurological symptoms |
| Concerning examination e.g. midline tenderness, neurological deficit, midline pain on coughing |
| Mobilisation problems e.g. pain or new neurological signs on mobilising |
Examination
This will depend on the situation. Often in major trauma, full examination of the back may be delayed until the secondary survey, particularly if the patient is heading straight to scan. If suspected, it is important to examine the back whilst minimising movement, and so a log roll may be indicated. Alongside any visible deformity, and midline tenderness, it is important to document neurology in the lower limbs. One helpful guide for this is the ASIA scoring system5 which has helpful prompts for testing myotomes and dermatomes, as well as the ASIA grading system.
Investigation
So, we might have found some tenderness, or feel that the patient has a risky enough mechanism that we need to do some imaging, what kind of imaging?
NICE gives some slightly conflicting advice suggesting that lumbar x-ray should be performed 1st line if spinal column injury is suspected without neurology, but then also saying a CT should be done if there are signs or symptoms of a spinal column injury.
In terms of sensitivity there is evidence that lumbar spine x-rays may miss clinically important spine injuries with one paper suggesting that the sensitivity of x-rays for these is about 66%.4 So why do NICE recommend x-ray as their first line choice? Looking through the evidence section for this guideline NICE acknowledge that x-ray will have a higher rate of false negatives compared to CT but they have balanced this with the fact that CT brings a potential 100-fold increase in radiation to the patient, and still has a risk of a false negative report.
Overall it all comes down to risk. The negative likelihood ratio of x-ray is estimated at an unimpressive 0.43. If you have a patient who seems high risk, a CT might be a better option as even with a normal x-ray your post-test probability will still be high enough to be concerned about a serious spinal injury, particularly in older patients who may have abnormal anatomy to begin with. In addition, NICE recommend that for any patient with neurology, an MRI is recommended, even if a CT is normal.
And lastly remember that one fracture in the spine immediately raises the risk of spinal fractures elsewhere, so consider the need for full spine imaging if concerned.
Types of spinal injury
The scan comes back with a wedge fracture in L1. What now?
As with most things in medicine, there are multiple ways to classify spine injuries, but one common way is the AO thoracolumbar classification. This is helpful as it starts at the most severe (e.g. dislocation) and progresses towards a less severe set of injuries. It is important to note, however, even the lower risk A-type injuries, including wedge fractures, have the potential to be unstable. Generally, wedge fractures that involve >30 degrees of kyphosis or loss of 50% of anterior height, have potential for instability.6 If in doubt, a discussion with your spinal team is recommended. They will want to know about neurological status as this will factor into their risk assessment.
Management in ED
If a spinal fracture is confirmed we need advice from the spinal team (which may be either orthopaedics or neurosurgery, depending on where you are) with regards to management. If the fracture is confirmed as stable, management generally involves analgesia and careful mobilisation, which may need to happen on a ward if the patient is struggling. If unstable, the advice would be for full spinal precautions, lying the patient flat and using log rolling for turns. Remember if you find one fracture in the spine, the suspicion should be increased for spinal injury elsewhere and you should consider the need for more imaging if not already performed.
References
- Hasler RM, Exadaktylos A, Bouamra O, Benneker L, Clancy M, et al. Epidemiology and predictors of spinal injury in adult major trauma patients: European cohort study. Eur Spine J. 2011 Dec;20(12):2174-80.
- National Institute for Health and Care Excellence (NICE). Spinal injury: assessment and initial management. NICE Guideline NG41, Feb 2016.
- Inaba K, Nosanov L, Menaker J, Bosarge P, Williams L, Turay D, et al. Prospective derivation of a clinical decision rule for thoracolumbar spine evaluation after blunt trauma: An American Association for the Surgery of Trauma Multi-Institutional Trials Group Study. Journal of Trauma and Acute Care Surgery. 2015 Mar 6;78(3):459-467.
- VandenBerg J, Cullison K, Fowler SA, et al. Blunt Thoracolumbar-Spine Trauma Evaluation in the Emergency Department: A Meta-Analysis of Diagnostic Accuracy for History, Physical Examination, and Imaging. J Emerg Med. 2019 Feb;56(2):153-165.
- International Standards for Neurological Classification of Spinal Cord Injury. American Spinal Injury Association (ASIA), International Spinal Cord Society (ISCOS), 2019. [Accessed 05 Aug 2024]
- White TO, Mackenzie SP, Gray AJ. McRae’s Orthopaedic Trauma and Emergency Fracture Management. 3rd ed. Edinburgh: Elselvier; 2016.