What are the Nexus low risk criteria (Nexus low risk criteria) for evaluating cervical spine injury in trauma patients?

NEXUS Low-Risk Criteria for Cervical Spine Injury

The NEXUS low-risk criteria consist of five clinical factors that, when ALL are absent, allow clinicians to safely forgo cervical spine imaging in blunt trauma patients with 99.6% sensitivity and 99.9% negative predictive value. 1

The Five NEXUS Criteria

Cervical spine imaging is NOT required if ALL five of the following are absent: 1

• No midline cervical tenderness - Absence of pain on palpation of the posterior midline cervical spine 1, 2
• No focal neurologic deficit - No motor or sensory deficits, including absence of paresthesias in extremities 1, 2
• Normal level of alertness - Patient is fully conscious and oriented 1, 2
• No intoxication - No evidence of alcohol or drug intoxication that could mask symptoms 1, 2
• No painful distracting injury - No other significant painful injury that could distract from cervical spine pain 1, 2

If even ONE of these five criteria is present, cervical spine imaging is indicated. 1

Performance Characteristics

The NEXUS criteria were validated in a prospective multicenter study of 34,069 blunt trauma patients, demonstrating: 1

• Sensitivity: 99.6% (95% CI: 98.6%-100%) for clinically significant injury 1
• Negative predictive value: 99.9% (95% CI: 99.8%-100%) 1
• Specificity: 12.9% - meaning the criteria are intentionally over-inclusive to avoid missing injuries 1

Each individual criterion is essential; removing any single criterion would markedly reduce sensitivity and make the instrument unacceptable for clinical use, as each criterion was the sole indicator of injury in at least 5 patients with significant cervical spine injury. 3

Critical Age-Related Caveat

In patients >65 years of age, the standard NEXUS criteria have reduced sensitivity (66-89%), which is unacceptably low. 1

For elderly patients, add two additional criteria to restore 100% sensitivity: 1

• Injury to the face or head
• Deviations from baseline mental status

Clinical Application Algorithm

Step 1: Assess all five NEXUS criteria before considering imaging 1

Step 2: If ALL five criteria are absent (patient is low-risk):

• No cervical spine imaging required 1
• Remove cervical collar 1
• Clinically clear the patient 1

Step 3: If ANY criterion is present:

• Proceed with cervical spine imaging 1, 2
• CT is the preferred modality (98.5% sensitivity, 99.97% NPV) 1
• MRI is indicated if neurological deficits are present 2, 4

Common Pitfalls to Avoid

Do not attempt to clear the cervical spine clinically in patients with distracting injuries or intoxication, even if they deny neck pain, as these conditions mask symptoms. 2 Each of the five criteria exists because patients with only that single abnormality have been found to have significant cervical spine injuries. 3

Application of NEXUS criteria can reduce unnecessary cervical spine imaging by approximately 20-24%, avoiding radiation exposure, cost, and complications from prolonged cervical collar placement. 1, 5

In obtunded patients who cannot be clinically evaluated, imaging is mandatory regardless of NEXUS criteria, as the decision rule requires patient cooperation for assessment. 2

The criteria perform well in children aged 8 years and older (100% sensitivity in pediatric validation), but use caution in infants and toddlers under age 2 due to limited data in this age group. 6