National Emergency X-Radiography Utilization Study

Incomplete

Hoffman. "Validity of a Set of Clinical Criteria to Rule OutInjury to the Cervical Spine in Patients with Blunt Trauma". NEJM. 2000. 343(2):94-99.
PubMed

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Clinical Question

Among blunt trauma patients, can a set of clinical criteria safely identify patients who can forego cervical imaging?

Bottom Line

Low acuity blunt trauma patients can safely forego cervical spine imaging if they meet the following clinical criteria: 1. Absence of tenderness at the posterior midline of the cervical spine 2. Normal alertness/mentation 3. No focal neurologic deficits 4. Absence of intoxication 5. Absence of distracting injuries

Major Points

Cervical spinal injuries are important to identify early due to their high, largely irreversible morbidity. However, as relatively rare sequelae of trauma (~6%), routine radiography overexposes patients to radiation and is not cost effective. The NEXUS study validated a decision instrument in a low-acuity blunt trauma population based on 5 criteria: 1. Absence of tenderness at the posterior midline of the cervical spine 2. Normal alertness/mentation 3. No focal neurologic deficits 4. Absence of intoxication 5. Absence of distracting injuries. Within low-acuity populations, NEXUS allowed clinicians to safely forego cervical imaging.

The Nexus Low Risk criteria (NLC) has been compared against another notable set of clinical criteria, the Canadian C-spine Rule (CCR) , and studies have sought to compare the two . Both the NLC and CCR are valid, clinically useful instruments.

Guidelines

• no guidelines to date

Design

• N = 34,069 patients
  • 818 (2.4%) radiographically defined cervical-spine injury
• Prospective, observational study
• Physician filled out form documenting clinical criteria
• radiologists blinded to clinical findings
• 21 institutions
• Clinically non-significant injuries defined as: spinous-process fracture, wedge-compression fracture without loss of 25% or more of vertebral-body height, isolated avulsion without associated ligamentous injury, Type I odontoid fracture, end-plate fracture, osteophyte fracture (not including corner/teardrop), trabecular bone injury, transverse-process fracture
• Primary endpoint: to determine the sensitivity of the decision instrument
• Secondary endpoints: Positive predictive value, negative predictive value, sensitivity, specificity
• Further methodology

Population

Inclusion Criteria

• Blunt trauma mechanism
• Cervical spine imaging

Exclusion Criteria

• penetrating trauma
• cervical imaging performed for nontraumatic reasons

Baseline Characteristics

• Male 58.7% overall (64.8% male cervical spine injury)
• 2.4% radiographically documented cervical spine injury
• Pediatrics (<8 years old) overall 2.5% (1.3% among cervical spinous injuries)

Interventions

• 3-series of cervical spine (cross-table lateral view, anteroposterior view, open mouth odontoid view)
• CT/MRI as adjunctive views

Outcomes

“Data are Presented for Any Injury, and Clinically Significant Injury”

Primary Outcomes

• False negative rate for decision instrument, among clinically significant c-spine injuries 0.3% (2/578)
• False negative rate for decision instrument among all c-spine injuries 2.4% (8/818)

Secondary Outcomes

Patients with Clinically Significant Injuries

Sensitivity 99.6 (98.6–100)

Specificity 12.9 (12.8–13.0)

Negative Predictive Value 99.9 (99.8–100)

Positive Predictive Value 1.9 (1.8–2.0)

All Patients

Sensitivity 99.0 (98.0–99.6)

Specificity 12.9 (12.8–13.0)

Negative Predictive Value 99.8 (99.6–100)

Positive Predictive Value 2.7 (2.6–2.8)

Screening for Clinically Significant Injury, Radiographically Documented Injury

Positive Clinical Screening (1.9%) 810/29760

Negative Clinical Screening (< 0.05%) 2/4301

Any Injury, Radiographically Documented Injury

Positive Clinical Screening (2.7%) 810/29760

Negative Clinical Screening (< 0.2%) 8/4301

Subgroup Analysis

• No subgroup analysis performed

Adverse Events

• No adverse events were reported

Criticisms

• Most patients evaluated were low acuity, as demonstrated by lower than nationally documented cervical spine injury rate of 6%
• No control for demographic information
• No formal definition of distracting injury, multiple definitions of
• May not be appropriate for elderly (age > 60) and severe blunt trauma due to low sensitivity
• No specific analysis for pediatric population

Funding

• Agency for Healthcare Research and Quality RO1 Grant (HS08239)