Clearing the Cervical Spine

Ronald W. Lindsey

Zbigniew Gugala

Clearing the cervical spine is among the highest priorities in the early assessment of trauma patients in emergency centers. Annually, more than 10 million trauma patients in the United States present to emergency centers, and the possibility of cervical spine injury must be considered in the majority of these patients (1, 2 and 3). However, the incidence of cervical spine injury among blunt trauma patients is only 1% to 3% (4, 5, 6 and 7). Consequently, there is a pressing need for the emergency assessment of the trauma patient to include a concise, yet thorough, approach to cervical spine clearance.

Traditionally, most physicians have considered imaging the principal, if not the sole, method by which the cervical spine should be cleared. This opinion created a tendency for many physicians to ignore the merits of the history and physical examination in the clearance process and impeded the development of reliable clinical indicators of cervical injury. Therefore, most clinicians/institutions initially developed their own cervical spine clearance protocols that rely entirely on indiscriminate imaging (8). The liberal use of imaging typically produces a large number of predominantly normal or inadequate cervical spine x-rays, creates frequent delays in the patient’s emergency workup and subsequent treatment, and culminates in an immense expenditure of both personnel time and institutional resources (9, 10 and 11).

Despite the numerous problems associated with an indiscriminate use of imaging in the trauma setting, this practice has been difficult to restrict. Although the history and physical examination are integral components of the cervical spine evaluation, there is no consensus among physicians on how to best prioritize the impact of these clinical components on the diagnostic process. When cervical spine injury is missed and/or its treatment delayed, subsequent patient morbidity can be devastating and an enormous cost incurred by society. Finally, for most physicians, the potential liability of a missed cervical spine injury more than justifies clearance protocols based upon routine x-ray imaging.

More than two decades ago, Jacobs and Schwartz (12) established that the ability of emergency physicians to clinically predict the presence of cervical spine injury in trauma patients was only 50%. However, these same authors were able to successfully determine the absence of cervical spine injury in 94% of trauma patients without cervical spine injury. Inadvertently, this study emphasized that the true focus of cervical spine clearance is accurately determining the absence of cervical spine injury. It also affirmed that the clinical designation of absence of cervical spine injury was more feasible than cervical spine injury detection.

Because of the exceptionally low incidence of positive imaging findings, the process of clearing the cervical spine is extremely inefficient when it is solely dependent on imaging. In a retrospective series of 1,686 consecutive trauma patients who underwent cervical spine clearing, Lindsey et al. (13) questioned the efficacy of routine cervical spine imaging. These authors identified cervical spine injuries in only 1.9% of patients; moreover, nearly all of the detected cervical spine injuries were nonthreatening to the patients’ spine stability or neurologic integrity. These findings suggest that the concept of a specific clinical protocol to more selectively identify trauma patients who warrant imaging has enormous merit.

The objective of this chapter is to explore the complex issue of clearing the cervical spine in trauma patients. Among the topics addressed are (a) defining cervical spine clearance, its rationale, and objectives; (b) identifying the specific trauma patient groups that present to the emergency center for cervical spine clearance; (c) establishing the clinical and imaging components of clearance; (d) reviewing the currently available guidelines for clearing the cervical spine; and (e) devising a new comprehensive algorithm to clear the cervical spine in the emergency setting in accordance with the specific patient groups identified.

CERVICAL SPINE CLEARANCE: DEFINITION, RATIONALE, OBJECTIVES

The overwhelming majority of blunt trauma victims presenting to the emergency center do not have cervical spine injury (14). In order to reliably and effectively identify the patients who are injury free, the term “clearance” of the cervical spine has recently been introduced to and accepted by emergency medicine centers and physicians (15). Cervical spine clearance in the trauma setting
is defined as reliably ruling out the presence of cervical spine injury in a patient who does not have a cervical spine injury. Contrary to the common misconception, cervical clearance is not intended to detect or classify an injury or determine the most appropriate treatment. Clearance simply declares that a cervical spine injury is not present. The cervical spine clearing process always requires a complete clinical evaluation and occasionally warrants adjunctive imaging. Clearance should, ideally, occur at the earliest point of the trauma patient’s assessment at which it can be reliably accomplished. However, the clearance process does not place its major emphasis on how quickly it is accomplished, but on its accuracy.

The fundamental objective of cervical spine clearance is to improve the efficiency, accuracy, and effectiveness of the entire trauma assessment process. When cervical spine injury can be reliably ruled out, neck immobilization precautions can be discontinued, additional neck diagnostic or therapeutic modalities are not warranted, and the trauma evaluation can focus on other areas of potential injury. Considerable pressure is often placed on the emergency clinician to expeditiously clear the cervical spine, especially when the index of suspicion for injury is low. However, one should accept that some patients simply cannot be cleared in the acute setting. If cervical spine injury cannot be reliably excluded, vigilant cervical spine precautions should be maintained, and efforts to establish a definitive position on the status of the cervical spine must continue.

CERVICAL SPINE CLEARANCE PATIENT GROUPS

Two basic principles are applied to all blunt trauma patients in regard to the cervical spine clearance process (16). First, a meaningful clinical examination is imperative before cervical spine clearance can be accomplished. The fundamental prerequisite is a lucid patient; therefore, the initial step in the clearance process is to determine the patient’s level of alertness (Tables 27.1 and 27.2). Although all patients should be thoroughly evaluated, only fully alert patients (Ransohoff Class I, Glasgow Coma Scale [GCS] >14) are capable of undergoing a dependable physical examination, and these individuals constitute the only type of patients in whom a cervical injury can be reliably ruled out, with or without supplemental imaging. Secondarily, alert, oriented patients should be assessed in respect to the presence or absence of symptoms that can either be attributed to or possibly mask cervical spine injury. These masking symptoms include intoxication, head injury, and major distracting injuries. On the basis of these principles, all blunt trauma patients can be acutely categorized into three cervical spine patient clearance groups (15) (Table 27.3):

TABLE 27.1 Ransohoff Classification of Consciousness Levels

Class	Description
1	Alert; responds immediately to questions; may be disoriented and confused; follows complex commands
2	Drowsy, confused, uninterested; does not lapse into sleep when undisturbed; follows simple commands only
3	Stuporous; sleeps when not disturbed; responds briskly and appropriately to noxious stimuli
4	Deep stupor; responds defensively to prolonged noxious stimuli
5	Coma; no appropriate response to any stimuli; includes decorticate and decerebrate responses
6	Deep coma; flaccidity; no response to any stimuli
Adapted from Ransohoff J, Fleischer A. Head injuries. JAMA 1975;234:861-864. Ref. (17).

TABLE 27.2 Glasgow Coma Scale

Feature	Response	Score
Eye opening	Spontaneous	4
	To speech	3
	To pain	2
	None	1
Verbal response	Oriented	5
	Confused conversation	4
	Words inappropriate	3
	Sounds incomprehensible	2
	None	1
Best motor response	Obeys commands	6
	Localizes pain	5
	Flexion normal	4
	Flexion abnormal	3
	Extended	2
	None	1
Total Coma Score		3-15

GROUP I (ASYMPTOMATIC)

Patients who can be reliably cleared by clinical examination alone without imaging (i.e., no plain radiography,
computed tomography [CT], magnetic resonance imaging [MRI], etc.) constitute Group I. Patients in this group must satisfy all five of the following criteria (18): (a) full alertness, (b) no intoxication, (c) no midline tenderness, (d) no focal neurologic deficit, and (e) no distracting painful injury (Table 27.4). A randomized, prospective study of 34,069 patients by the National Emergency X-Radiography Utilization Study (NEXUS) group (14) demonstrated that significant cervical spine injury could be reliably excluded by physical examination alone when applying these criteria. The reliability of cervical spine clearance by physical examination of the alert patient has also been supported by other studies (13,19,20). Patients who are successfully cleared clinically do not require further diagnostic measures, and cervical spine precautions can be discontinued.

TABLE 27.3 Cervical Spine Clearance Patient Groups

Group	Designation		Patient Characteristics
I	Asymptomatic		Awake, fully alert
			No intoxication
			No neck pain/tenderness
			Normal neurologic function
			No distracting injury
II	Symptomatic		Awake, fully alert
			Neck pain and/or tenderness
			Neurologic deficit
III	Nonevaluable	Temporarily	Intoxicated (alcohol, drugs)
III	Nonevaluable	Temporarily	Presence of distracting injury
		Indefinitely	Obtunded (brain injury)
			Intubated
			Pharmacologic coma

GROUP II (SYMPTOMATIC)

Fully oriented and alert patients who demonstrate symptoms of neck pain, tenderness, neurologic deficit, and decreased mobility on physical examination require additional diagnostic assessment to effectively clear the cervical spine and comprise Group II. This group also includes patients with a distracting injury or a past history of cervical spine pathology and symptoms. Additional diagnostic studies typically consist of at least three-view radiography (anteroposterior [AP], lateral, open-mouth odontoid) and may require adjunctive CT or MRI (15). Voluntary lateral flexion-extension radiography is indicated only after symptomatic treatment has failed over a brief period of time (typically 2 weeks); flexion-extension radiography is not generally recommended in the acute setting. An alert patient who presents with a partial or complete neurologic deficit is assumed to have a spine injury and thereby always requires imaging. Whether the deficit is due to spinal cord, spinal root, or peripheral nerve injury, an exhaustive diagnostic effort must be made to rule out spine instability and/or injury. Throughout this process, the physician must strictly adhere to all precautionary spine immobilization techniques, even if the initial examination suggests a complete neurologic deficit. Plain radiography and/or sophisticated imaging are always indicated to diagnose and categorize the injury. Prophylactic modalities such as high-dose steroid administration, when indicated, must be instituted emergently. Serial clinical examinations, ideally by the same physician, are recommended, whether the patient’s neurologic deficit is partial or complete, to document neurologic progression or improvement during the workup.

TABLE 27.4 Clinical Cervical Spine Clearance Criteria as Defined by the NEXUS Group

1.	Altered neurologic function is present if any of the following is present: (a) GCS score of 14 or less; (b) disorientation to person, place, time, or events; (c) inability to remember three objects at 5 minutes; (d) delayed or inappropriate response to external stimuli; or (e) any focal deficit on motor or sensory examination. Patients with none of these individual findings should be classified as having normal neurologic function.
2.	Patients should be considered intoxicated if they have either of the following: (a) a recent history of intoxication or intoxicating ingestion, or (b) evidence of intoxication on physical examination. Patients may also be considered to be intoxicated if tests of bodily secretions are positive for drugs that affect level of alertness, including a blood alcohol level >0.08 mg/dL.
3.	Midline posterior bony cervical spine tenderness is present if the patient complains of pain on palpation of the posterior midline neck from the nuchal ridge to the prominence of the first thoracic vertebra, or if the patient evinces pain with direct palpation of any cervical spinous process.
4.	Patients should be considered to have a distracting painful injury if they have any of the following: (a) a long bone fracture; (b) a visceral injury requiring surgical consultation; (c) a large laceration, degloving injury, or crush injury; (d) large burns; or (e) any other injury producing acute functional impairment. Physicians may also classify any injury as distracting if it is thought to have the potential to impair the patient’s ability to appreciate other injuries.
Adapted from Hoffman JR, Wolfson AB, Todd K, et al. Selective cervical spine radiography in blunt trauma: methodology of the national Emergency X-Radiography Utilization Study (NEXUS). Ann Emerg Med 1998;32:461-469.

GROUP III (NONEVALUABLE)

Patients who cannot be cleared at the time of the emergency center assessment constitute Group III (15). Definitive clearance is not feasible in this group due to the patient’s medical instability, the patient’s inability to undergo a reliable clinical examination, or inconclusive results of the initially performed diagnostic studies. Most patients in this group present with an impaired level of consciousness owing to head injury or intoxication, and this alone inhibits the clearance process. Although adjunctive imaging in this group, when positive, can detect cervical injury, it cannot, when negative, definitively rule it out. This group typically consists of two subgroups: patients who are temporarily nonevaluable and those who are indefinitely nonevaluable. The temporarily nonevaluable patients include those who are intoxicated or have a distracting injury. These patients can be asymptomatic, but the presence of intoxication and/or distracting injury renders their clinical examination unreliable. The expectation is that the temporary inhibiting condition(s) will resolve in 24 to 48 hours, and these patients can
subsequently be reclassified to either patient Group I or II. The subgroup of indefinitely nonevaluable patients include those who are obtunded, intubated, and/or pharmacologically compromised, and therefore they cannot submit to a meaningful clinical examination. Strict adherence to the principles of cervical spine external support and/or stabilizing precautions is recommended for all Group III patients. The emergency imaging performed on these patients is intended to solely detect possible cervical spine injury, but not to definitively exclude it. When cervical spine imaging of Group III patients is negative, there is a strong tendency for the trauma team to simply accept this as formal clearance; however, the prudent physician is obliged to maintain all neck precautions until the patient becomes alert and amenable to meaningful clinical assessment. Although some reports (21, 22, 23 and 24) suggest that negative sophisticated imaging (CT and/or MRI) may adequately clear the cervical spine of these patients, the authors submit that definitive clearance cannot be reliably established until the patient is alert and a valid physical examination can be performed.

The efficiency of cervical spine clearance can be greatly enhanced by assigning patients to one of these three groups. Although one of the primary clinical objectives will always be to increase the sensitivity of cervical injury detection, the emergency clinician must recognize that the true challenge of clearance is to be as proficient as possible in the specificity of cervical spine injury exclusion. Indeed, the inability to clinically clear a patient is not equivalent to the presence of injury and always requires the use of adjunctive imaging. However, most imaging modalities are more sensitive for injury detection than they are specific for its exclusion. Therefore, cervical spine imaging alone cannot substitute for a thorough clinical evaluation in establishing clearance. Furthermore, the effectiveness of imaging in cervical spine clearance is enhanced when combined with a meaningful clinical examination.

PATIENT MANAGEMENT BEFORE AND DURING CERVICAL SPINE CLEARANCE

In prehospital trauma management, cervical spine injury should be assumed present in all patients. Cervical spine immobilization is uniformly applied and typically consists of a cervical collar and/or securing the head to the backboard with tape and/or sandbags (25,26). Although neck immobilization in trauma patients has been questioned because of reported elevations in intracranial pressure and an increased risk for respiratory problems (27), routine rigid neck immobilization is still recommended as the standard for all trauma patients (28).

After arrival at the hospital, all external neck support should be maintained. These principles apply even during the assessment of the airway; the head and neck should never be excessively flexed, extended, or rotated at this juncture. If external neck support must be temporary removed (e.g., neck wound inspection), a member of the trauma team should be given the sole responsibility of manually maintaining control of the head and neck using in-line immobilization techniques (25). The trauma physician’s strict adherence to the precautions cannot be overstated; prior to the implementation of these recommendations, it had been reported that a significant subset of cervical trauma patients experienced the onset or progression of neurologic deficit after arrival at the hospital (29). The first premise in clearing trauma patients for cervical injury is the assumption that a cervical spine injury exists and should be managed accordingly until it can be definitely excluded (9).

If other injuries warrant immediate or greater attention, the cervical spine evaluation can be safely deferred as long as cervical immobilization is diligently maintained. The only aspects of the initial assessment of the trauma patient that are of greater priority than the cervical spine are the patient’s airway, breathing, circulation, and head/brain. A patent airway should be expeditiously identified or established immediately after the trauma patient’s arrival to the hospital. Breathing must then be documented or external ventilation initiated. Hemorrhage, the most prevalent cause of preventable deaths post trauma, must be quickly controlled to ensure hemodynamic stability (25). Finally, a neurologic evaluation is performed to establish the patient’s level of consciousness and, if a brain injury exists, it must also be managed emergently. Cervical spine clearance becomes the focus of the evaluation only after these “ABCs” have been addressed.

The cervical spine screening begins with the assignment of each patient to one of the three previously described patient groups following a brief clinical examination. Most published clearance guidelines address the oriented and alert patient and have become well established and/or accepted (14,30, 31, 32, 33, 34 and 35). However, for the indefinitely nonevaluable (obtunded) patients (Group III), the initial evaluation protocols are controversial (36, 37, 38, 39 and 40).

CLINICAL CLEARANCE OF THE CERVICAL SPINE

HISTORY

A detailed history is essential in the cervical spine assessment of trauma patients. The initial priority in obtaining a valid history is an early, accurate determination of the patient’s level of alertness. Although the ideal history is one obtained from an alert, oriented trauma victim, significant information is also available from a host of other individuals who may have experienced the same mishap or are simply familiar with the scene of the accident (e.g., police, emergency medical technicians, other passengers, witnesses). In addition to documenting the mechanism of injury, the history should provide a detailed account of the events and patient’s condition from immediately postinjury up to the time of presentation to a medical facility. Information regarding the victim’s past medical history, especially as it pertains to previous cervical spine conditions, is especially helpful. Special attention should be given to the elderly patient who has sustained a fall or minor trauma; these individuals, many of whom have preexisting neck symptoms due to extensive degenerative
disease, are particularly susceptible to cervical spine injury that may go undetected (41,42).

The risk for cervical spine injury and its severity can often be directly correlated with the energy associated with the traumatic insult (12,20,43). Therefore, the level of energy (i.e., high vs. low) and the manner by which injury is sustained (direct vs. indirect) are crucial information. The clinician should determine if the accident is the result of a high-speed motor vehicle crash (MVC) or a fall from a considerable height versus an altercation. If due to a fall, the approximate height of the fall should be calculated; if due to an MVC, the record should reflect if the patient was restrained or ejected from the vehicle. The possibility of direct versus indirect whiplash injury should also be established.

The previously noted study by Jacobs and Schwartz (12) not only established the feasibility of clinical clearance of the cervical spine but also identified a number of subjective variables that seemed to correlate with an increased risk for cervical spine injury (Table 27.5). In a recent study, Stiell et al. (31) calculated odds ratios for several clinical variables that could predict a significant cervical spine injury (Table 27.6). Although these variables may serve to heighten one’s awareness of the risk for cervical spine injury in a particular patient, ruling out the presence of these variables alone does not establish cervical clearance.

PHYSICAL EXAMINATION

The physical examination, albeit challenging in the acute posttraumatic environment, is essential for valid clearance of the cervical spine. This principle exists regardless of whether adjunctive imaging is also deemed necessary to complete the process. The physical examination can only be accomplished in patients who demonstrate a GCS score >14, and therefore, it is feasible only for patients from Groups I and II. Unlike the obtunded patients in Group III, the alert and oriented Group I and II patients can participate in a physical examination that must demonstrate their ability to respond to complex commands, voluntarily mobilize their neck, indicate symptomatic anatomic regions, and undergo a comprehensive neurologic evaluation. Group II patients, although suitable for physical examination, are not candidates for clinical clearance, and they must undergo appropriate imaging to complete a valid clearing process. Only Group I patients can be definitively cleared by clinical assessment alone if it is normal.

TABLE 27.5 Statistical Significance of Variables Predictive for Cervical Spine Injury

Variable	p Value
Motor vehicle accident	0.052
Fall >10 feet (>3 m)	0.007
Neck tenderness	0.002
Numbness	0.001
Loss of sensation	0.001
Weakness	0.001
Neck spasm	0.001
Loss of muscle power (0-5)	0.001
Decreased sensation	0.001
Loss of anal tone/wink	0.001
Fall <10 feet (<3 m)	0.083
Low energy injury	0.700
Drug/alcohol intoxication	0.400
Flexion/extension	0.400
Compression/torsion	0.960
Head trauma	0.370
Neck pain	0.140
Headache	0.140
Loss of consciousness	0.382
Bradycardic hypotension	0.760
Adapted from Jacobs LM, Schwartz R. Prospective analysis of acute cervical spine injury: a methodology to predict injury. Ann Emerg Med 1986;15:44-49.

TABLE 27.6 Odds Ratios of Clinical Variables Predicting Clinically Significant Cervical Spine Injury

Variable	OR (95% CI)
Dangerous mechanism^a	5.2 (3.7-7.3)
Age ≥ 65 y	3.7 (2.4-5.6)
Paresthesia in extremities	2.2 (1.4-3.3)
Ambulatory at any time after injury	1.0 (0.7-1.5)
Sitting position in emergency center	0.61 (0.3-1.2)
Delayed onset of neck pain	0.4 (0.3-0.7)
Absence of midline neck tenderness	0.5 (0.3-0.8)
Able to rotate neck 45° left and right	0.04 (0.01-0.3)
Simple rear-end MVC^b	0.08 (0.03-0.2)
Notes:^a^aFall from ≥ 3 feet (1 m); axial load to the head; highspeed MVC, rollover, or ejection; bicycle collision; recreational motorized vehicle collision. ^b^bExcludes vehicle pushed into oncoming traffic, hit by bus or large truck, rollover, or hit by high-speed vehicle. OR, odds ratio; CI, confidence interval; MVC, motor vehicle crash. Adapted from Stiell IG, Wells GA, Vandemheem KL, et al. The Canadian C-Spine Rule for radiology in alert and stable trauma patients. JAMA 2001;286:1841-1848.

The initial cervical spine physical examination of the trauma patient should consist of a static assessment. At this stage, the physical examination is performed while the external cervical support remains in place, the neck is not manipulated, and the patient is maintained in a supine posture. The static stage components of the physical examination that have positively correlated with cervical spine injury include the presence of neck pain, focal neck tenderness or spasm, and/or neurologic deficits (12,44). Neurologic deficit of any degree precludes the ability to achieve clinical clearance, and adjunctive cervical spine imaging is mandatory (15). Many clinicians suggest that cervical spine injury should be assumed present
in the neurologically compromised patient until further workup can conclusively establish its absence. Particular attention must be given to patients who sustain direct face, head, or neck trauma (45, 46, 47 and 48). Although neck injury usually occurs through an indirect injury mechanism, (e.g., whiplash), patients who sustain direct trauma above the shoulders are at particularly significant risk for cervical spine injury.

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