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Annals of Internal Medicine

Cervical Spine Clearance in Obtunded Patients After Blunt Traumatic Injury A Systematic Review Jetan H. Badhiwala, MD; Chung K. Lai, BHSc; Waleed Alhazzani, MD; Forough Farrokhyar, PhD; Farshad Nassiri, MD; Maureen Meade, MD; Alireza Mansouri, MD; Niv Sne, MD; Mohammed Aref, MD; Naresh Murty, MD; Christopher Witiw, MD; Sheila Singh, MD, PhD; Blake Yarascavitch, MD; Kesava Reddy, MD; and Saleh A. Almenawer, MD

Background: Cervical spine clearance protocols are controversial for unconscious patients after blunt traumatic injury and negative findings on computed tomography (CT). Purpose: To review evidence about the utility of different cervical spine clearance protocols in excluding significant cervical spine injury after negative CT results in obtunded adults with blunt traumatic injury. Data Sources: MEDLINE, EMBASE, CINAHL, Google Scholar, and the Cochrane Library were searched from January 2000 through November 2014. Study Selection: English-language studies that examined patients with negative CT results having confirmatory routine testing with magnetic resonance imaging (MRI), dynamic radiography, or clinical examination and that reported outcome measures of missed cervical spine injury, need for operative stabilization, or prolonged use of cervical collars. Data Extraction: Independent reviewers evaluated the quality of studies and abstracted the data according to a predefined protocol.

C

ervical spine trauma is a major public health problem and a common reason for admission to trauma wards and intensive care units. The cervical spine is injured in 2.3% to 4.3% (1– 4) of blunt traumas. Resultant neurologic impairment is encountered in 33% to 54% (5–7) of patients with cervical spine trauma. In fact, more than 50% of all acute spinal cord injuries affect the cervical spine (8, 9). Unfortunately, these injuries have poor functional outcomes. Mortality after traumatic cervical spinal cord injury may exceed 20% (10 – 13), and survivors often face lifelong physical disability, along with the associated emotional, psychological, and social burdens (6, 8, 14, 15). The economic costs of spinal cord injury are enormous. In the United States, the total annual direct cost of spinal cord injuries approaches $8 billion (16). These factors make diligent and efficient cervical spine clearance protocols a critical priority. The exclusion of cervical spine injury in obtunded patients with trauma poses a significant challenge given the lack of a reliable clinical examination. Common practices at many trauma centers include routine acquisition of cervical spine magnetic resonance imaging (MRI), dynamic radiography (flexion and extension), or continued cervical immobilization until patients are awake and asymptomatic after a negative computed tomography (CT) scan (17, 18). These protocols may increase health care costs unduly, place critically ill pa-

Data Synthesis: Of 28 observational studies (3627 patients) that met eligibility criteria, 7 were prospective studies (1686 patients) with low risk of bias and well-interpreted, high-quality CT scans. These 7 studies showed that 0% of significant injuries were missed after negative CT results. The overall studies using confirmatory routine testing with MRI showed incidence rates of 0% to 1.5% for cervical spine instability (16 studies; 1799 patients), 0% to 7.3% for need for operative fixation (17 studies; 1555 patients), and 0% to 29.5% for prolonged collar use (16 studies; 1453 patients). Limitations: Most studies were retrospective. Approaches to management of soft tissue changes with collars varied markedly. Conclusion: Cervical spine clearance in obtunded adults after blunt traumatic injury with negative results from a wellinterpreted, high-quality CT scan is probably a safe and efficient practice. Primary Funding Source: None. Ann Intern Med. 2015;162:429-437. doi:10.7326/M14-2351 www.annals.org For author affiliations, see end of text.

tients at risk for deterioration during transportation, and prolong cervical collar immobilization and its associated illnesses. On the other hand, the consequences of missing an injury can be devastating and may include loss of functional ability, independence, and possibly life (19 –21). The primary aim of this study was to elucidate the role for further routine imaging or prolonged cervical immobilization in excluding significant cervical spine injury after negative CT results in obtunded patients who had blunt traumatic injury.

METHODS This systematic review was done according to a predefined protocol (Supplement, available at www .annals.org) in accordance with MOOSE (Meta-analysis Of Observational Studies in Epidemiology) guidelines (22) and the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) Statement (23).

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REVIEW Search Strategy We searched MEDLINE (PubMed and Ovid), EMBASE, CINAHL, Google Scholar, and the Cochrane Library from January 2000 through November 2014 for studies on the role of CT followed by a validating test in evaluating the cervical spine of obtunded trauma patients. We used, in various combinations, keywords and Medical Subject Headings terms pertinent to the patient population (altered, comatose, intensive care, intubated, mental status, obtunded, unconscious, unevaluable, unexaminable, unreliable, or unresponsive), medical condition (fracture, injury, instability, or trauma), anatomical site of interest (cervical-spine or cervical), and relevant radiological imaging methods (clearance, computed tomography, CT, dynamic, extension, flexion, fluoroscopy, imaging, magnetic resonance, MDCT, MR, MRI, plain film, radiograph, or X-ray). We also manually searched the references of relevant studies to identify additional studies for consideration. Selection Criteria Three investigators independently evaluated the studies for eligibility. Selection criteria included a study of any design (randomized, controlled trial; prospective cohort study; or retrospective cohort study). Studies were eligible if the diagnostic protocol of interest included a negative finding on a helical CT scan of the entire cervical spine followed by a confirmatory test. We included only the population of obtunded patients with blunt trauma (Glasgow Coma Scale [GCS] score ≤14, unreliable clinical examination, or intubation). Only English-language studies documenting the outcome measures of missed cervical spine injury or intervention after a negative CT result and additional findings of a validating test were included. We excluded studies with a sample size of fewer than 10 patients and studies in which partial cervical spine CT scans were used. For studies reporting data on overlapping cohorts from the same institution, we included only the study with the most inclusive cohort to prevent duplication. Studies evaluating only the pediatric population were excluded. Studies that examined awake and obtunded patients were included only if the outcomes of unreliable patients were analyzed separately. Abstracts from meeting proceedings were excluded if the data were not published in full-text articles in a peerreviewed journal. Disagreements among the 3 reviewers about the decision to include or exclude a study were resolved by consensus and, if necessary, consultation with a fourth reviewer. Data Extraction and Quality Assessment Data from eligible studies were independently extracted by the 3 primary reviewers and verified for accuracy by the fourth reviewer. Discrepancies were resolved by discussion and consensus. We used data collection forms that included the following fields: title, author, year and country of publication, study design, sample size, patient demographic characteristics, Injury Severity Score, GCS score, definition of “obtunded,” mechanism of injury, CT specifications, further imaging or follow-up of patients with negative CT scans, image

Cervical Spine Clearance in Obtunded Patients

interpreter, missed acute cervical spine injuries, and changes in management. The 3 primary reviewers performed quality assessment independently. We used the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool (24) and examined patient selection, the index test and reference standard used, and flow and timing to determine whether the risk of bias and concerns about applicability to the review question were low, unclear, or high among eligible studies. Definition of Variables Our primary outcome of interest was clinically significant cervical spine injury missed by CT and detected by the confirmatory test. A clinically significant injury was defined as one resulting in mechanical instability or requiring intervention or change in management. We excluded soft tissue signal changes that did not affect spine stability. The definition of cervical spine instability varied among included studies and was assessed by using many classification systems. Most eligible studies defined instability in accordance with the work of White and Panjabi (25) on biomechanics of the spine. Previous studies defined unstable and purely ligamentous injuries as those involving all 3 columns (26). We adopted and documented cervical spine instability outcomes as reported by the authors of included studies, regardless of the classification used. Changes in management after negative CT results and positive findings on a validating test included prolonged external immobilization or operative stabilization. An obtunded patient was defined as someone who was not fully awake and had an altered level of consciousness (GCS ≤14). These patients lacked a reliable neurologic examination that could aid in the diagnosis of spinal injury. High-quality CT scans were defined as those protocolled with narrow slice width (1 to 3 mm) and reconstruction in multiple planes. A well-interpreted CT study was defined as an image read by a health professional with special training and expertise in reading such images (that is, a consultant radiologist) rather than an on-call physician or radiology resident. Data Synthesis and Analysis Studies were grouped on the basis of how further evaluation of obtunded trauma patients with negative results from cervical spine CT was handled. The first group included studies that routinely performed MRI after a CT scan that was interpreted as normal. The second group comprised studies in which patients were routinely evaluated with dynamic radiography after negative CT results. The third group included studies in which patients were followed with serial physical examination after a normal CT result, with further imaging obtained as guided by clinical indications (for example, neurologic deficit). For each group, we examined mechanical cervical spine instability, need for operative stabilization, and collar use after negative CT results and additional findings on the confirmatory test. We examined high-quality studies separately. These reports fulfilled 4 criteria: prospective study design, low risk of bias and low concerns about applica-

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bility in all domains on the QUADAS-2 tool, wellinterpreted CT images, and use of high-quality CT specifications. Given the small number of events (if any), formal meta-analysis was not possible. Data from individual studies are displayed in forest plots with 95% CIs. Exact binominal 1-sided 95% CIs were calculated for each proportion obtained from eligible studies (27). We used R, version 3.1.2 (R Foundation for Statistical Computing), to generate all forest plots. Role of the Funding Source This study received no funding.

RESULTS Characteristics of Included Studies Our search yielded 2112 results, of which 1959 were excluded after title and abstract screening. Another 125 were excluded after full-text review (Appendix Figure, available at www.annals.org). The remaining 28 studies (28 –55) were included, and they reported on a total of 3627 obtunded blunt trauma patients with negative results from cervical spine CT and a validating test. Twenty studies (28, 29, 32, 34, 35, 37, 40 – 44, 46, 48 –55) were retrospective cohort studies, and 8 (30, 31, 33, 36, 38, 39, 45, 47) were prospective cohort studies. Descriptions of eligible studies are provided in Appendix Tables 1 and 2 (available at www.annals.org). Details of methodological assessment of included studies with the QUADAS-2 tool are presented in Appendix Table 3 (available at www.annals.org). Routine MRI Twenty studies (28, 29, 32–37, 41– 44, 46, 48 –52, 54, 55) with a total of 2099 patients reported on the routine use of MRI during the follow-up of obtunded adult patients with blunt trauma and negative results from cervical spine CT. Of these, 16 studies (28, 32–34, 36, 37, 41– 44, 49 –52, 54, 55) (1799 patients) reported data on incidence of unstable cervical spine injury, 17 (28, 33–37, 41– 44, 46, 48 –50, 52, 54, 55) (1555 patients) reported incidence of operative fixation, and 16 (28, 29, 33–37, 41– 44, 46, 48, 51, 52, 55) (1453 patients) reported incidence of neck immobilization. Incidences of cervical spine instability, surgical intervention, and prolonged collar use after routine MRI ranged from 0% to 1.5%, from 0% to 7.3%, and from 0% to 29.5%, respectively (Figure 1). Collar use after negative CT results and additional findings on MRI related to soft tissue signal changes varied markedly across studies. In some studies, collars were always discontinued after soft tissue signal changes on MRI (28, 30, 34, 36, 44, 55), in contrast to other studies (29, 35, 37, 41– 43, 46, 48, 51, 52) with higher incidence of collar use. This is probably attributable to the management styles of physicians involved in these studies. Clinical Examination Follow-up Five studies (30, 31, 38, 47, 53) described 728 obtunded adult patients with blunt traumatic injury and negative results from a cervical spine CT. Neck immobilization was discontinued and the cervical spine was

cleared clinically once patients became evaluable. These patients were followed clinically, with serial physical examination and further imaging obtained only as needed on the basis of clinical indications rather than as part of a routine protocol, and interventions were instituted as deemed necessary. All but 1 of these studies (53) had prospective designs. In all, no patients went on to have a diagnosis of unstable cervical spine injury, and none required operation or cervical collar replacement (Figure 2). Routine Dynamic Imaging In 3 studies (39, 40, 45) with a total of 800 patients, further routine dynamic images were obtained after normal CT scans in obtunded adult patients. Incidences of unstable cervical spine injury and operative intervention ranged from 0% to 0.2%, and incidence of prolonged collar use after dynamic radiography was 0% (Figure 3). High-Quality Studies We examined higher-quality studies separately. These were more robust studies with prospective designs, low risk of bias, and higher-quality CT specifications and interpretation. Seven studies (30, 31, 33, 36, 38, 39, 47) with a total of 1686 patients fulfilled these criteria. The rates of missed cervical spine instability, need for operative intervention, or need for collar immobilization after negative CT results and further confirmatory testing were all 0% (Figure 4).

DISCUSSION Findings from our systematic review suggest that in obtunded blunt trauma patients, cervical spine clearance after negative results from a well-interpreted, high-quality CT scan is a safe and efficient practice that may obviate the need for routine adjunct imaging or prolonged neck immobilization. Although routine MRI may detect a few spinal soft tissue signal changes missed by CT, these are mechanically stable injuries, and the use of rigid collars in these cases varied markedly across studies on the basis of the management styles of the physicians involved. Cervical spine clearance in patients who had an unreliable neurologic examination after blunt traumatic injury is a common clinical scenario encountered in trauma and intensive care units and has been the center of ongoing debate. This controversy about the optimal practice is reflected in the updated guidelines for the management of acute cervical spine and spinal cord injury published in 2013. Recommendations were made for obtunded patients to continue cervical immobilization until they become asymptomatic, discontinue cervical immobilization after a normal MRI study, or discontinue immobilization at the discretion of the treating physician after normal results from high-quality CT imaging (18). The primary reason to adopt routine follow-up imaging after negative CT results in obtunded patients is rooted in the potentially catastrophic consequences of a missed injury. Reid and colleagues (21) reported the emergence of secondary neurologic

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Figure 1. Forest plots of effect sizes for missed cervical spine injury (top), surgical intervention (middle), and collar use (bottom) after negative computed tomography results and additional findings on magnetic resonance imaging. Total, n

Study, Year (Reference)

Events, n

Kihiczak et al, 2001 (28)

0

19

0.000 (0.000–0.176)

Hogan et al, 2005 (32)

0

366

0.000 (0.000–0.010)

Schuster et al, 2005 (33)

0

12

0.000 (0.000–0.265)

Adams et al, 2006 (34)

0

20

0.000 (0.000–0.168)

Como et al, 2007 (36)

0

115

0.000 (0.000–0.032)

Sarani et al, 2007 (37)

0

46

0.000 (0.000–0.077)

Menaker et al, 2008 (41)

1

203

0.005 (0.000–0.027)

Steigelman et al, 2008 (42)

0

120

0.000 (0.000–0.030)

Tomycz et al, 2008 (43)

2

180

0.011 (0.001–0.040)

Schoenwaelder et al, 2009 (44)

0

55

0.000 (0.000–0.065)

Khanna et al, 2012 (49)

0

150

0.000 (0.000–0.024)

Soult et al, 2012 (50)

0

24

0.000 (0.000–0.142)

Chew et al, 2013 (51)

0

132

0.000 (0.000–0.028)

Fisher et al, 2013 (52)

3

196

0.015 (0.003–0.044)

Satahoo et al, 2014 (54)

0

106

0.000 (0.000–0.034)

Tan et al, 2014 (55)

0

55

0.000 (0.000–0.065)

Kihiczak et al, 2001 (28)

0

19

0.000 (0.000–0.176)

Schuster et al, 2005 (33)

0

12

0.000 (0.000–0.265)

Adams et al, 2006 (34)

0

20

0.000 (0.000–0.168)

Stassen et al, 2006 (35)

0

44

0.000 (0.000–0.080)

Como et al, 2007 (36)

0

115

0.000 (0.000–0.032)

Sarani et al, 2007 (37)

0

46

0.000 (0.000–0.077)

Menaker et al, 2008 (41)

2

203

0.010 (0.001–0.035)

Steigelman et al, 2008 (42)

0

120

0.000 (0.000–0.030)

Tomycz et al, 2008 (43)

0

180

0.000 (0.000–0.020)

Schoenwaelder et al, 2009 (44)

0

55

0.000 (0.000–0.065)

Menaker et al, 2010 (46)

1

96

0.010 (0.000–0.057)

Kaiser et al, 2012 (48)

0

114

0.000 (0.000–0.032)

Khanna et al, 2012 (49)

0

150

0.000 (0.000–0.024)

Soult et al, 2012 (50)

0

24

0.000 (0.000–0.142)

Fisher et al, 2013 (52)

2

196

0.010 (0.001–0.036)

Satahoo et al, 2014 (54)

1

106

0.009 (0.000–0.051)

Tan et al, 2014 (55)

4

55

0.073 (0.020–0.176)

Proportion (95% CI)

0

0

0.05

0.05

0.1

0.15

0.1

0.2

0.15

0.2

0.25

0.25

0.3

0.3

Kihiczak et al, 2001 (28)

0

19

0.000 (0.000–0.176)

Ghanta et al, 2002 (29)

2

46

0.043 (0.005–0.148)

Schuster et al, 2005 (33)

0

12

0.000 (0.000–0.265)

Adams et al, 2006 (34)

0

20

0.000 (0.000–0.168)

Stassen et al, 2006 (35)

13

44

0.295 (0.168–0.452)

Como et al, 2007 (36)

0

115

0.000 (0.000–0.032)

Sarani et al, 2007 (37)

4

46

0.087 (0.024–0.208)

Menaker et al, 2008 (41)

14

203

0.069 (0.038–0.113)

Steigelman et al, 2008 (42)

2

120

0.017 (0.002–0.059)

Tomycz et al, 2008 (43)

16

180

0.089 (0.052–0.140)

Schoenwaelder et al, 2009 (44)

0

55

0.000 (0.000–0.065)

Menaker et al, 2010 (46)

7

96

0.073 (0.030–0.144)

Kaiser et al, 2012 (48)

6

114

0.053 (0.020–0.111)

Chew et al, 2013 (51)

21

132

0.159 (0.101–0.233)

Fisher et al, 2013 (52)

4

196

0.020 (0.006–0.051)

Tan et al, 2014 (55)

0

55

0.000 (0.000–0.065) 0

0.1

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0.2

0.3

0.4

0.5

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deficits in 4 (10.5%) of 38 patients with delayed diagnosis of spinal fracture. Davis and colleagues (20) documented delayed or missed diagnosis of cervical spine injury in 34 (4.6%) of 740 patients. The physical, emotional, and psychological suffering of patients and their families resulting from such disability or loss of life is profound and immeasurable (56). Avoidance of these consequences has been considered the key motivator for excessive use and reliance on further routine cervical spine imaging (57–59). In contrast, routine cervical spine work-up after negative CT results is costly and time-consuming, poses potential risks to critically ill patients during the transfer process, and may unnecessarily extend rigid collar immobilization that can lead to accompanying complications. In an analysis of the published literature in 2008, Dunham and colleagues (60) documented that prolonged cervical spine collar use was associated with a 26.2% probability of increasing intensive care unit complications, including pressure ulcers, delirium, and ventilator-associated pneumonia. Furthermore, MRI carried a 9.3% to 14.6% risk for secondary brain injury during transportation and a 20.6% probability of aspiration during scanning. In addition to these risks, excessive use of MRI can add significantly to the burden on the health care system by unnecessarily increasing costs and wasting hospital resources and personnel time without providing critical information. A

clinical test is considered useful, and therefore necessary, if it changes patient management. In our systematic review, further imaging after negative CT results or prolonged collar use resulted in no added benefits based on higher-level evidence. Only 10 of 1555 patients had operative intervention after cervical spine MRI. These patients were obtained from retrospective studies with concerns about the quality of scan specifications and the accuracy of CT image interpretation. Collar use after negative CT results and additional findings on MRI related to soft tissue signal changes varied markedly across studies (range, 0% to 29.5%). This was attributed primarily to varying thresholds of prolonged collar use among trauma centers with different individual preferences between managing physicians, which may be biased by several confounding factors. First, physicians who use a protocol of routine follow-up imaging after negative CT results may generally favor more conservative approaches and, hence, prolonged collar use. Second, the act of obtaining a follow-up MRI or radiograph may itself result in keeping the collar in place for longer periods until full images are obtained and a decision is made. Third, this practice might be explained by the difficulty experienced by managing physicians in discontinuing the collar early after minor MRI findings, even if they are not related to mechanical stability of the cervical spine but

Figure 2. Forest plots of effect sizes for missed cervical spine injury (top), surgical intervention (middle), and collar use (bottom) after negative computed tomography results and additional findings on clinical examination follow-up. Study, Year (Reference)

Events, n

Total, n

Widder et al, 2004 (30)

0

84

0.000 (0.000–0.043)

Brohi et al, 2005 (31)

0

326

0.000 (0.000–0.011)

Stelfox et al, 2007 (38)

0

68

0.000 (0.000–0.053)

Como et al, 2011 (47)

0

197

0.000 (0.000–0.019)

Raza et al, 2013 (53)

0

53

0.000 (0.000–0.067)

Proportion (95% CI)

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Widder et al, 2004 (30)

0

84

0.000 (0.000–0.043)

Brohi et al, 2005 (31)

0

326

0.000 (0.000–0.011)

Stelfox et al, 2007 (38)

0

68

0.000 (0.000–0.053)

Como et al, 2011 (47)

0

197

0.000 (0.000–0.019)

Raza et al, 2013 (53)

0

53

0.000 (0.000–0.067) 0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Widder et al, 2004 (30)

0

84

0.000 (0.000–0.043)

Brohi et al, 2005 (31)

0

326

0.000 (0.000–0.011)

Stelfox et al, 2007 (38)

0

68

0.000 (0.000–0.053)

Como et al, 2011 (47)

0

197

0.000 (0.000–0.019)

Raza et al, 2013 (53)

0

53

0.000 (0.000–0.067) 0

0.01

0.02

0.03

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0.04

0.05

0.06

0.07

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are instead used as a defensive act against potential catastrophic events. Ultimately, this practice obtained from retrospective studies was not replicated in higherquality prospective evidence and was not supported by any documentation of cervical spine mechanical instability. An English-language search of MEDLINE from January 2000 to November 2014 showed few reviews published on this topic. In 2011, a review of 17 studies of the literature (61) suggested that cervical collars may be removed from obtunded trauma patients if a modern CT scan yields negative results for acute injury. This conclusion was based on a calculated sensitivity and specificity of more than 99.9% for modern CT. These calculations, however, were based on studies with highly mixed populations of all blunt trauma patients and were not limited to obtunded patients, which is contrary to the central aim of our study. Moreover, the review did not include injuries requiring collar immobilization after negative CT results in calculations of sensitivity and specificity and used an aggressive definition of purely ligamentous unstable injury (all 3 columns injured at a single level). These factors and others limit the generalizability of the study results. A review published in 2013 (62) of 13 studies with a total of 1322 patients calculated negative predictive values for negative CT results of 92.9% for clinically significant injury and 99.6% for injury requiring operative intervention without calculating exact effect sizes of included studies. Although this study concluded that CT of the cervical spine must be supplemented by an additional ex-

amination addressing ligamentous instability, it only included MRI as the additional examination, which leaves out other potential methods for evaluating ligamentous injury, such as dynamic radiography and clinical examination. Other reviews missed studies meeting their inclusion criteria, examined mixed and heterogeneous patient populations, or failed to clearly delineate the utility of cervical spine CT given the small number of included studies (53, 63– 65). None of these reviews evaluated higher-quality evidence separately or examined outcomes obtained from well-interpreted and high-quality CT scans, which is essential because these factors may influence the results of CT image accuracy. The primary strength of our study is the use of rigorous methods in evaluating the utility of CT imaging by strictly including resources that have validated the accuracy of CT scans through further routine imaging or clinical examination. Each of the confirmatory tests (MRI, dynamic radiography, or clinical examination) was evaluated separately. Furthermore, 3 distinct outcomes (spine mechanical instability, surgical intervention, and prolonged collar use) were measured for each validating test after negative CT results. Moreover, we examined higher-quality studies separately to evaluate evidence obtained from more robust studies that used higher-quality diagnostic imaging with optimal interpretation. Our study is limited, however, by the lack of randomized, controlled trials in the literature and the predominance of retrospective rather than prospective observational study designs. In addition, we could not calculate the positive and negative predictive values,

Figure 3. Forest plots of effect sizes for missed cervical spine injury (top), surgical intervention (middle), and collar use (bottom) after negative computed tomography results and additional findings on dynamic imaging. Study, Year (Reference)

Events, n

Total, n

Proportion (95% CI)

Anekstein et al, 2008 (39)

0

31

0.000 (0.000–0.112)

Harris et al, 2008 (40)

0

367

0.000 (0.000–0.010)

Hennessy et al, 2010 (45)

1

402

0.002 (0.000–0.014)

0

0.05

0.1

0.15

0.2

Anekstein et al, 2008 (39)

0

31

0.000 (0.000–0.112)

Harris et al, 2008 (40)

0

367

0.000 (0.000–0.010)

Hennessy et al, 2010 (45)

1

402

0.002 (0.000–0.014)

0

0.05

0.1

0.15

0.2

Anekstein et al, 2008 (39)

0

31

0.000 (0.000–0.112)

Harris et al, 2008 (40)

0

367

0.000 (0.000–0.010)

Hennessy et al, 2010 (45)

0

402

0.000 (0.000–0.009)

0

0.05

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0.1

0.15

0.2

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Figure 4. Forest plots of effect sizes for missed cervical spine injury (top), surgical intervention (middle), and collar use (bottom) after a well-interpreted, high-quality computed tomography scan and additional findings on confirmatory testing. Study, Year (Reference)

Events, n

Widder et al, 2004 (30)

0

84

0.000 (0.000–0.043)

Brohi et al, 2005 (31)

0

326

0.000 (0.000–0.011)

Schuster et al, 2005 (33)

0

12

0.000 (0.000–0.265)

Como et al, 2007 (36)

0

115

0.000 (0.000–0.032)

Stelfox et al, 2007 (38)

0

68

0.000 (0.000–0.053)

Anekstein et al, 2008 (39)

0

31

0.000 (0.000–0.112)

Como et al, 2011 (47)

0

197

0.000 (0.000–0.019)

Total, n

Proportion (95% CI)

0

0.05

0.1

0.15

0.2

0.25

0.3

Widder et al, 2004 (30)

0

84

0.000 (0.000–0.043)

Brohi et al, 2005 (31)

0

326

0.000 (0.000–0.011)

Schuster et al, 2005 (33)

0

12

0.000 (0.000–0.265)

Como et al, 2007 (36)

0

115

0.000 (0.000–0.032)

Stelfox et al, 2007 (38)

0

68

0.000 (0.000–0.053)

Anekstein et al, 2008 (39)

0

31

0.000 (0.000–0.112)

Como et al, 2011 (47)

0

197

0.000 (0.000–0.019) 0

0.05

0.1

0.15

0.2

0.25

0.3

Widder et al, 2004 (30)

0

84

0.000 (0.000–0.043)

Brohi et al, 2005 (31)

0

326

0.000 (0.000–0.011)

Schuster et al, 2005 (33)

0

12

0.000 (0.000–0.265)

Como et al, 2007 (36)

0

115

0.000 (0.000–0.032)

Stelfox et al, 2007 (38)

0

68

0.000 (0.000–0.053)

Anekstein et al, 2008 (39)

0

31

0.000 (0.000–0.112)

Como et al, 2011 (47)

0

197

0.000 (0.000–0.019) 0

0.05

sensitivity, and specificity of CT scans because we did not include patients with positive CT findings. Our current method allowed us to include more studies from the literature and examine precisely the incidence of missed injuries after a normal CT image and, therefore, CT study accuracy. Despite its limitations, our study is an attempt to provide a well-documented, comprehensive review and critical appraisal of the data in the literature pertaining to the utility of CT among obtunded patients. In summary, cervical spine clearance in obtunded adults after blunt traumatic injury with negative results from a well-interpreted, high-quality CT scan is probably a safe and efficient practice. Indeed, higher-quality evidence indicates no added benefits from prolonged cervical spine immobilization or further imaging. The practice of continued collar use after normal CT scans and additional signal changes from MRI varied markedly across studies, and data were obtained only

0.1

0.15

0.2

0.25

0.3

randomly from retrospective design studies without evidence of clinical necessity. Future studies should attempt to delineate the outcomes of benefits, relative risks, and cost-effectiveness of continued cervical immobilization or further imaging in a randomized study design. From the University of Toronto, Toronto, Ontario, Canada; McMaster University, Hamilton, Ontario, Canada; and University of Texas Southwestern Medical Center, Dallas, Texas. Disclosures: Authors have disclosed no conflicts of interest. Forms can be viewed at www.acponline.org/authors/icmje /ConflictOfInterestForms.do?msNum=M14-2351. Requests for Single Reprints: Saleh A. Almenawer, MD, Divi-

sion of Neurosurgery, Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada; e-mail, Dr_menawer @hotmail.com.

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REVIEW Current author addresses and author contributions are available at www.annals.org.

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Current Author Addresses: Drs. Badhiwala, Nassiri, Mansouri,

and Witiw: Division of Neurosurgery, University of Toronto, 563 Spadina Crescent, Toronto, Ontario M5S 2J7, Canada. Drs. Lai, Aref, Murty, Singh, Reddy, and Almenawer: Division of Neurosurgery, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada. Drs. Alhazzani and Meade: Division of Critical Care, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada. Dr. Farrokhyar: Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada. Dr. Sne: Department of Surgery, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4L8, Canada. Dr. Yarascavitch: Department of Neurological Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390.

Author Contributions: Conception and design: J.H. Badhiwala, C.K. Lai, W. Alhazzani, F. Farrokhyar, S.A. Almenawer. Analysis and interpretation of the data: J.H. Badhiwala, C.K. Lai, F. Farrokhyar, F. Nassiri, M. Meade, C. Witiw, S. Singh, S.A. Almenawer. Drafting of the article: J.H. Badhiwala, C.K. Lai, B. Yarascavitch, S.A. Almenawer. Critical revision of the article for important intellectual content: J.H. Badhiwala, W. Alhazzani, F. Farrokhyar, F. Nassiri, M. Meade, A. Mansouri, N. Sne, M. Aref, N. Murty, C. Witiw, S. Singh, B. Yarascavitch, K. Reddy, S.A. Almenawer. Final approval of the article: J.H. Badhiwala, W. Alhazzani, F. Farrokhyar, F. Nassiri, M. Meade, A. Mansouri, N. Sne, M. Aref, N. Murty, C. Witiw, S. Singh, B. Yarascavitch, K. Reddy, S.A. Almenawer. Provision of study materials or patients: S.A. Almenawer. Statistical expertise: F. Farrokhyar, F. Nassiri, S.A. Almenawer. Administrative, technical, or logistic support: B. Yarascavitch, S.A. Almenawer. Collection and assembly of data: J.H. Badhiwala, C.K. Lai, W. Alhazzani, A. Mansouri, S.A. Almenawer.

Appendix Figure. Summary of evidence search and selection.

Potentially relevant citations identified through electronic literature search and manual screening of reference lists (n = 2112)

Duplicate records excluded (n = 507)

Resources evaluated by title and abstract screening (n = 1605)

Records excluded after full-text assessment (n = 125) No relevant study cohort of patients: 77 Evaluated a diagnostic test other than plain CT: 42 Performed CT scan of only part of the cervical spine: 4 Studied pediatric patients only: 2

Full-text articles reviewed (n = 153)

Records excluded after title and abstract screening (n = 1452) No relevant study population, treatment, or outcome Letters to editor Editorials or commentaries Meeting abstracts Case reports Reviews

Citations included in systematic review (n = 28 [3627 patients])

CT = computed tomography.

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United States

Ghanta et al, 2002 (29) Widder et al, 2004 (30) Brohi et al, 2005 (31) Hogan et al, 2005 (32)

Schoenwaelder et al, 2009 (44) Hennessy et al, 2010 (45) Menaker et al, 2010 (46) Como et al, 2011 (47) Kaiser et al, 2012 (48) Khanna et al, 2012 (49)

Menaker et al, 2008 (41) Steigelman et al, 2008 (42) Tomycz et al, 2008 (43)

Sarani et al, 2007 (37) Stelfox et al, 2007 (38) Anekstein et al, 2008 (39) Harris et al, 2008 (40)

Stassen et al, 2006 (35) Como et al, 2007 (36)

Schuster et al, 2005 (33) Adams et al, 2006 (34)

United States

Kihiczak et al, 2001 (28)

19

Patients, n

United States

United States

United States

United States

Canada

Australia

United States

United States

United States

United States

Israel

Canada

Retrospective cohort Prospective cohort Retrospective cohort Prospective cohort Retrospective cohort Retrospective cohort 150

114

197

96

402

55

Retrospective 203 cohort Retrospective 120 cohort Retrospective 180 cohort

Retrospective 46 cohort Prospective 68 cohort Prospective 31 cohort Retrospective 367 cohort

United States

United States

20

12

Retrospective 44 cohort Prospective 115 cohort

Prospective cohort Retrospective cohort

Retrospective 46 cohort Prospective 84 cohort Prospective 326 cohort Retrospective 366 cohort

Retrospective cohort

Study Design

United States

United States

United States

United States

United Kingdom

Canada

Country

Study, Year (Reference)

Appendix Table 1. Characteristics of Included Studies

36.0

39.0

47.3

44.2

40.0

37.5

43.7

33.0

42.3

40.2

36.0

ND

ND

43.9

ND

39.3

49.1

42.1

ND

ND

ND

ND

Mean Age, y

Male: 144 Female: 53 Male: 84 Female: 30 Male: 101 Female: 49

Male: 42 Female: 13 Male: 321 Female: 81 ND

Male: 135 Female: 68 Male: 81 Female: 39 Male: 138 Female: 42

Male: 24 Female: 7 Male: 277 Female: 90

ND

ND

Male: 90 Female: 25

ND

Male: 8 Female: 4 Male: 15 Female: 5

Male: 281 Female: 85

ND

ND

ND

ND

Sex

5.9

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

ND

Mean GCS Score

Obtunded or comatose (GCS score ≤13) and no gross motor deficit

Persistently unreliable examination (GCS score ≤14) Obtunded and gross movement of all extremities GCS score ≤14

Intubated

Intubated (clinically unassessable)

ND

8.0

6.7

9.5

11.8

ND

Persistently unreliable clinical examination 9.7 (GCS score ≤14) Altered mental status or unreliable ND physical examination Obtunded (GCS score ≤13) and no ND evidence of sensory or motor deficit

Altered mental status

Comatose (GCS score

Cervical spine clearance in obtunded patients after blunt traumatic injury: a systematic review.

Cervical spine clearance protocols are controversial for unconscious patients after blunt traumatic injury and negative findings on computed tomograph...
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