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Which patients with blunt trauma need cervical spine imaging?
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Clinical Decision Rule for Cervical Spine Imaging after Blunt Trauma:

A Summary of  the NEXUS Criteria and the Canadian C-Spine Rule

 Summary Dr. Elizabeth Dei Rossi






Which patients with blunt trauma need cervical spine imaging?  What are the differences between the decision rules available? What are the potential pitfalls of these rules?
Every year, hundreds of thousands of people are involved in blunt trauma accidents; it is the job of the emergency physician to decide which patients need imaging to rule out cervical spine injury.  Missed injuries can result in severe neurologic disability and this has historically led doctors to order many radiographs which are frequently negative in order to avoid missing injuries.
There are two major clinical decision rules that have been developed to try to permit more selective ordering of radiographs in order to eliminate excessive ordering and thereby reduce the burden on the healthcare system and allow for quicker patient disposition in the emergency department.
NEXUS Criteria
Methods: prospective observational study with 21 participating centers across the United States, Participating centers included both university and community hospitals and hospitals with and without residents.  34,039 patients who underwent radiography following blunt trauma were evaluated using 5 criteria. Radiographs were either three-view XRAY imaging, CT or MRI.

Low probability must meet all of the following criteria: if low probability then no imaging is necessary.
1.       No midline cervical tenderness
2.       No focal neurologic deficit – motor or sensory
3.       Normal alertness – considered abnormal if GCS < 14, disorientation to person/place/time/events, inability to remember 3 objects at 5 minutes, delayed or inappropriate response to external stimuli
4.       No intoxication – assessed by history from patient, observers, physical exam, and lab tests
5.       No painful, distracting injury – no precise definition developed by Nexus study.  Distracting injuries include but are not limited to any long bone fracture, visceral injury, large lacerations, degloving injury, crush injury, large burns.
Results: 818 injuries were identified, 8 of which were considered low probability by the criteria, and 2 of those 8 were considered to have clinical significance
Sensitivity 99%, negative predictive value 99.8%,
Specificity 12.9%, positive predictive value 2.7
Estimated 12.6 % reduction in number of films ordered if apply Nexus criteria
Canadian C-spine Rule
Methods:  prospective observational study with 10 participating centers across Canada, Participating centers included both university and community hospitals.  8924 adult patients who underwent radiography following blunt trauma were evaluated using 20 criteria. Radiographs were either three view XRAY imaging or CT.
Exclusion criteria: younger than 16, GCS < 15, grossly abnormal vitals, were injured more than 48 hours previously, penetrating trauma, presented with acute paralysis, had known vertebral disease (ankylosing spondylitis, rheumatoid arthritis, spinal stenosis, or previous spinal surgery), pregnancy, returned for reassessment of the same injury
Outcome measure: clinically important injuries (fracture, dislocation, or ligamentous instability) unless the patient was neurologically intact and had either an isolated avulsion fracture of an osteophyte, isolate fracture of a transverse process not involving a facet joint, isolated fracture of a spinous process not involving the lamina, or a simple compression fracture involving less than 25% of the vertebral height

Some patient’s classified as low risk did not receive imaging and were concluded to have no clinically significant injury by telephone survey asking about questions about neck pain two weeks after the visit to the emergency room.
Any high risk factors mandates radiography:
  • Age >65
  • Dangerous mechanism
  • Fall from an elevation 3 ft or 5 stairs
  • An axial load to the head (ex. Diving injury)
  • Motor vehicle collision at high speed (>100 km/hr) or rollover or ejection
  • Rear end collision where car pushed into oncoming traffic
  • Motor vehicle collision involving a bus or large truck
  • Collision involving a motorized recreational vehicle or bicycle
  • Paresthesias in extremities
If no high risk factors and any of the following low risk factors and able to rotate neck actively 45 degrees, then no radiography needed.  If low risk factors present but unable to rotate neck actively 45 degrees then radiography needed.
If no low risk factors (below) are present then radiography indicated:  
·        Simple rear end motor vehicle collision
·        Sitting position in the emergency department
·        Ambulatory at any time
·        Delayed (not immediate) onset of neck pain
·        Absence of midline cervical spine tenderness
Results: 151 clinically important C-spine injuries, 28 clinically unimportant injuries
Sensitivity 100%
Specificity 42.5%
Estimated 15.5 % reduction in number of films ordered if apply Canadian C-spine Rule criteria
Take home message:
With the high sensitivity of both the NEXUS and Canadian c-spine rule, they are both appropriate decision making rules to use in order to rule out patients that do not need radiographs but have sustained blunt trauma.  The NEXUS study had less exclusion criteria and is applicable to all age groups versus the Canadian rules that are only applicable to adults.   The Canadian c-spine rule also used an endpoint of clinically significant injuries whereas the NEXUS criteria used an endpoint of all injuries that may contribute to the slightly lower sensitivity of the criteria.  There is also evidence to suggest that the Canadian c-spine rule may be superior to the NEXUS criteria in the elderly (age > 65), because the elderly have a higher pre-test probability of having a C-spine injury.
Future studies:
As CT scans have become an increasingly popular modality to evaluate C-spine injuries, both of these diagnostic criteria need to be evaluated using this imaging modality.   
Hoffman JR, Mower WR, Wolfson, AB, Todd, KN, Zucker, MI for the National Emergency X-Radiography Utilization Study Group. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. N Engl J Med 2000; 343:94-99.
Stiell IG, Wells GA, Vandemheen KL et al, The Canadian C-Spine Rule for Radiography in Alert and Stable Trauma Patients. Jama 2001;286(15):1841-1848.
Stiell IG, Clement CM, McKnight RD et al, The Canadian C-spine rule versus the NEXUS low-risk criteria in patients with trauma. N Engl J Med 2003 Dec 25;349(26):2510-8.
Touger M, Gennis P, Nathanson N, Lowery W, Pollack CV Jr, Hoffman Jr, Mower WR. Validity of a decision rule to reduce cervical spine radiography in elderly patients with blunt trauma.  Ann Emerg Med. 2002 Sep;40(3)287-93

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