Reference: Tavender E, et al. Triage tools for detecting cervical spine injury in paediatric trauma patients. Cochrane Database Syst Rev. 2024

Date: May 29, 2024

Guest Skeptic: Dr. Caleb Ward is a pediatric emergency medicine attending and Associate Professor of Pediatrics and Emergency Medicine at Children’s National Hospital and The George Washington School of Medicine and Health Sciences in Washington, DC. His research focuses on the pre-hospital care of children by EMS. He is the principal investigator for EMSC State Partnership in Washington, DC and is also involved in various multi-center EMS studies with the Pediatric Emergency Care Applied Research Network (PECARN).

Dr. Caleb Ward

Case: A 4-year-old boy is brought to the emergency department (ED) by Emergency Medical Services (EMS) after falling from a tall tree. The fall was witnessed by his family. They tell you that he is going through a Spiderman phase and tries to climb everything. They saw him slip off the tree and landed in the grass below. He did not have any loss of consciousness. EMS placed him in a C-collar and brought him to you. On examination, you only notice a few scrapes, but he is cradling his left arm and complaining that it hurts. There looks to be an obvious deformity of his forearm. The family members ask you, “he seems uncomfortable in the neck collar, can we remove it? Do you think he injured his neck?”

Background: Pediatric cervical spine injuries (CSI), though rare, can have devastating consequences if missed. Imaging studies include X-rays, CT scans, and MRIs. Typically, we see the use of X-ray or CT more often in the acute setting. The downside of these methods is exposing children to radiation. Clinical Decision Rules (CDRs) have been developed to help guide decision-making and minimize unnecessary tests and imaging while detecting significant injuries. Because there is no standardized process for identifying children with CSI after blunt trauma, practice varies based on clinician, institution, location, and available resources.

We have covered some of these CDRs in pediatrics on the SGEM before:

While there are CDRs for cervical spine injury in adults like the Canadian C-spine Rule and NEXUS criteria for C-spine imaging, we do not have a dedicated, accurate CDR for pediatric patients.

Clinical Question: Which triage tools or Clinical Decision Rules (CDRs) are most effective for detecting cervical spine injuries in pediatric trauma patients?

 Reference: Tavender E, et al. Triage tools for detecting cervical spine injury in paediatric trauma patients. Cochrane Database Syst Rev. 2024.

  • Population: Children (aged 0 to <18 years) who underwent blunt trauma evaluation in emergency departments. (ED)
    • Excluded: Patients with previous cervical spine surgery or congenital cervical spine anomalies
  • Intervention: Application of various CDRs or sets of clinical criteria to evaluate the presence of cervical spine injuries following blunt trauma.
  • Comparison: The CDRs were compared with each other and with reference standards like X-ray, CT, MRI, or clinical clearance/follow-up in low-risk children.
  • Outcome: The primary outcome of interest was the diagnostic accuracy of the CDRs, specifically their sensitivity and specificity in detecting cervical spine injuries.
  • Trial: Systematic review

Authors’ Conclusions: There is insufficient evidence to determine the diagnostic test accuracy of CDRs to detect CSIs in children following blunt trauma, particularly for children under eight years of age. Although most studies had a high sensitivity, this was often achieved at the expense of low specificity and should be interpreted with caution due to a small number of CSIs and wide CIs. Well-designed, large studies are required to evaluate the accuracy of CDRs for the cervical spine clearance in children following blunt trauma, ideally in direct comparison with each other.

Quality Checklist for Systematic Review Diagnostic Studies:

  1. The diagnostic question is clinically relevant with an established criterion standard. Yes
  2. The search for studies was detailed and exhaustive. Yes
  3. The methodological quality of primary studies were assessed for common forms of diagnostic research bias. Yes
  4. The assessment of studies was reproducible. Yes
  5. There was low heterogeneity for estimates of sensitivity or specificity. Unsure
  6. The summary diagnostic accuracy is sufficiently precise to improve upon existing clinical decision-making models. No
  7. Were there any declared financial conflicts of interest? No financial conflicts of interest

Results: The five included studies reported a total of 21,379 children, with age ranges from less than 3 years to under 18 years. Studies were conducted in various countries including the USA, UK, Australia, Canada, and Brazil. The median prevalence of CSI was 0.98% with IQR of 0.5% to 1.85%

CSI was defined as fracture, dislocation, ligamentous injury or spinal cord injury involving the cervical region.

The reference standard was X-ray, CT, MRI. In low-risk children who did not undergo imaging, follow-up (clinical evaluation in the ED) served as the reference standard. They also wanted information about additional follow-up after the ED in this population to avoid misclassification.

A total of 7 CDRs were included:

  1. PECARN retrospective criteria
  2. Canadian C-spine Rule
  3. NEXUS
  4. Leonard de novo
  5. National Institute for Health and Care Excellence (NICE) guideline CG56
  6. National Institute for Health and Care Excellence (NICE) guideline CG176

Key Results: Pediatric cervical spine injuries are rare and the existing CDRs have high sensitivity but low specificity. There is insufficient evidence to recommend one CDR over others for detecting CSIs in children.

1. Criterion Standard for CSI: One thing to flag up front is that the criterion standard used in the review and all of the papers included is just any CSI (fracture, dislocation, ligamentous injury or spinal cord injury – whether or not detectable on conventional imaging). This is not like head trauma CDRs where we talk about clinically significant intracranial injuries, rather than focusing on picking up a nondisplaced linear skull fracture.

We are skeptical that missing a tiny spinous process fracture or ligamentous strain is the same as missing a complete transection of a ligament with associated subluxation and cord impingement.

2. Sensitivity and Specificity: Sensitivity and specificity are often reported statistical terms. But what does this mean for our patients and practice when it comes to clinical decision rules and CSI?

Most decision rules had high sensitivity which means that they did accurately identify children who had CSI. However, the specificity was not great. This means that the CDRs cannot accurately identify kids who do not have CSI.

While this may be good in that we are not missing children with CSI, a CDR with low specificity can end up INCREASING the proportion of children who get imaging which potentially means that a large proportion of children are getting unnecessary radiation from imaging.

It is also important to note that even though the point estimates of sensitivities were high, the 95% confidence intervals for many of these studies were quite wide. The bottom range of these confidence intervals ranged from 0.48-0.88, reflecting the lack of true positive cases.

3. Bias: Biases are things that may systematically steer us away from the “truth.”

They did a thorough exploration of bias in four areas: 1) Patient selection 2) Index test 3) Reference standard 4) Flow and timing.

Under patient selection, two studies were considered at high risk of bias because they were retrospective studies looking at medical records and trauma registries.

Regarding the index test, two studies applied the index test retrospectively and were rated as high risk of bias. The other three had an unclear risk of bias because there was no information about the masking of imaging results before the interpretation of the index test. The authors mention that the development of a CDR is a three-step process: derivation, validation, and impact analysis. Two studies that derived a new CDR were high risk because of no validation.

The reference standard varied quite a bit amongst the studies. Two studies had some kind of radiographic imaging in all children. One study had imaging and clinical clearance in ED. Two studies had either imaging or clinical clearance in ED with follow-up phone calls.

One study had a low risk of bias. Three studies had an unclear risk of bias. One study had a high risk of bias (that is because there was no follow-up on discharged children).

For flow and timing (the authors had this mean “Did all patients receive the same reference standard.”), one study had a high risk of bias.

4. Clinical Judgement: Whenever we read about clinical decision rules or tools now, we have to wonder, “How do any of these CDRs compare to clinician judgement?” Some CDRs have criteria that one would deem almost kind of obvious. For example, if someone has a focal peripheral neurologic deficit and neck pain, we don’t need a CDR to tell us that they probably require imaging. Is it possible that our own clinical gestalt is better than any tool/rule out there?

Our colleague, Justin Morgenstern, of First10EM has a thought-provoking post titled, Clinical Decision Rules are Ruining Medicine.” We  would love to see more studies on CDRs compare them with clinician judgement.

Some of those studies have been done, and we must stay humble. Leonard’s team showed that for her cohort of kids in the 2009 study, 20% of children with a CSI were assessed by the treating physician as having a < 1% risk of CSI.

5. Applicability and Generalizability: When looking at a CDR, it is important to think about who is using it and in what setting. A few specific questions come to mind:

  • Would these CDRs perform as well in a community setting vs. a tertiary academic medical/trauma center? CDR might be of more use in those settings and may perform better – but that is not addressed in this paper, and the authors note that all the studies were conducted in largely well-resourced trauma or tertiary EDs (albeit located in different countries).
  • Who is entering data for the CDR? Specifically for injured children – the response may be interdisciplinary with general emergency medicine physicians, surgeons, pediatric emergency medicine physicians and trainees. This review does not probe into whether the CDRs have similar accuracy when used by different physician types.
  • Can these CDRs be applied in the prehospital settings by EMS clinicians? In the clinical vignette, the die had been cast, and the child was already in a collar. Studies show that placing a child in a collar and on a board sets in place a cascade of events – that can lead to pain, which we elicit as tenderness in the ED and then need to figure out – is this from the original injury or the collar that was placed by EMS. Case-control studies have shown that kids subject to spinal motion restriction are more likely to undergo imaging and be admitted to the hospital (when compared against matched kids with similar injury severity scores). It is important to ask whether CDRs have been validated in the prehospital setting

Bonus: What’s Coming…

The authors flag in their discussion section that two ongoing studies could shake this up. The first is being led by Julie Leonard in the PECARN network here in the US. This builds on the PECARN retrospective study and the Leonard de novo study they include in this review. In her latest study, she enrolled 22,000 children in a prospective observational study (including 433 with a cervical spine injury). Results in press currently at Lancet Child & Adolescent Health.

The second is a large study in Australasia comparing NEXUS, Canadian C-spine and PECARN rules head-to-head.

The other issue that is not fully addressed by this review article is the question of who needs a plain XR vs. who needs a CT.

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We agree with the authors’ conclusion.

SGEM Bottom Line: There are many CDRs for pediatric CSI. There is no conclusive evidence to recommend one over another.

Case Resolution: You examine the child after he receives some medication for his arm pain. He can obey all your commands. He has no neurological deficits. As you palpate his C-spine, he denies any midline tenderness. You carefully remove his C-collar and assess the range of movement of his neck. He has full range of motion and no pain, so you do not obtain any additional imaging at this time.

Clinical Application: Dr. Ward is polytheistic – takes the PECARN retrospective factors (diving, high-risk MVC, predisposing condition, altered mental status, torso injury, neck pain, torticollis, neuro deficits) + neck tenderness on the exam (NEXUS) – if none of those factors are present then the collar comes off.

It is easy enough to point out why each of these CDRs has challenges – estimates not very precise, lower specificity etc. but there is reason to believe that they are better than clinical gestalt, and if you are waiting on a perfect rule before being willing to adopt it, you might be waiting a long time…

What Do I Tell the Patient/Family? I’m sorry your child fell out of the tree. Despite the fall, he looks pretty good. He is not having neck pain currently, and I am not finding anything concerning on his neurological examination. I think we can take the C-collar off right now. We will need to get some X-rays of his arm to see if it is fractured.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics Guide to Emergency Medicine.