NEXUS C-Spine Criteria

The NEXUS (National Emergency X-Radiography Utilization Study) Low-Risk Criteria is a widely used clinical decision instrument that identifies blunt trauma patients who are at sufficiently low risk for cervical spine injury that imaging may be safely omitted. Developed through the landmark NEXUS study published in the New England Journal of Medicine in 2000, the criteria were derived from a prospective multicentre study of 34,069 blunt trauma patients at 21 US emergency departments. The NEXUS tool comprises five clinical criteria, all of which must be absent (i.e., all five conditions must be met) for a patient to be classified as low risk and eligible for C-spine clearance without imaging. The five criteria are: (1) no posterior midline cervical spine tenderness; (2) no evidence of intoxication; (3) normal level of alertness; (4) no focal neurological deficit; and (5) no painful distracting injury. The original study demonstrated a sensitivity of 99.6% and a specificity of 12.9% for detecting clinically significant cervical spine injuries, with only 8 significant injuries missed out of 818 in the low-risk group. Because the specificity is relatively low, the NEXUS tool significantly reduces but does not eliminate imaging. It is particularly valuable in busy emergency settings because the five criteria are simple, rapid to assess, and do not require special equipment. However, direct comparison studies (Stiell et al., CMAJ 2003) demonstrated that the Canadian C-Spine Rule (CCR) has higher specificity and performs better in alert, stable trauma patients, while NEXUS may be preferred in patients with lower GCS where the CCR cannot be applied.

1. 1Assess posterior midline cervical tenderness by palpating each spinous process and interspinous region from the occiput to T1 with the patient supine and the collar temporarily removed. Tenderness is defined as pain localised to the midline, not paraspinal or lateral, that is elicited or worsened by palpation.
2. 2Evaluate for intoxication: any clinical evidence of intoxication by alcohol or drugs that impairs the patient's ability to cooperate with the assessment constitutes a positive criterion. This includes slurred speech, ataxia, behavioural changes consistent with intoxication, or a blood alcohol level above legal limits.
3. 3Determine the level of alertness: the patient must be fully alert with a GCS of 15, oriented to person, place, time, and event, and able to provide a reliable history. Altered consciousness from any cause (head injury, medication, metabolic disorder) is a positive criterion.
4. 4Assess for focal neurological deficits: examine upper and lower limb motor and sensory function and note any deficit attributable to cervical cord or nerve root injury, including weakness, sensory loss, paraesthesias, or reflex changes. Pre-existing neurological deficits from non-acute causes must be carefully distinguished from acute injuries.
5. 5Evaluate for distracting painful injuries: a distracting injury is any injury that would impair the patient's ability to accurately report cervical pain. Examples include long bone fractures, visceral injuries, crush injuries, significant burns, or any other injury causing acute severe pain that might overwhelm or distract from the awareness of cervical spine symptoms.
6. 6If all five criteria are absent (i.e., the patient has no midline tenderness, is not intoxicated, is fully alert, has no neurological deficit, and has no distracting injury), the C-spine may be clinically cleared without imaging — document the assessment clearly.
7. 7If any single criterion is present, obtain cervical spine imaging: CT is preferred over plain radiographs for superior sensitivity; reserve MRI for neurological deficit or suspected ligamentous injury not visible on CT.