Canadian C-spine Rule and the National Emergency X-Radiography Utilization Low-Risk Criteria for C-spine radiography in young trauma patients

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1 Journal of Pediatric Surgery (2009) 44, Canadian C-spine Rule and the National Emergency X-Radiography Utilization Low-Risk Criteria for C-spine radiography in young trauma patients Peter F. Ehrlich, Christopher Wee, Robert Drongowski, Ankur R. Rana Section of Pediatric Surgery, Department of Surgery, The University of Michigan Medical School and The C.S. Mott Children's Hospital, Ann Arbor, MI 48109, USA Received 11 January 2009; accepted 15 January 2009 Key words: Clinical decision rule pediatric; Trauma; Cervical spine Abstract Purpose: The Canadian C-spine (cervical spine) Rule (CCR) and the National Emergency X- Radiography Utilization Low-Risk Criteria (NLC) are criteria designed to guide C-spine radiography in trauma patients. It is unclear how these 2 rules compare with young children. Methods: This study retrospectively examined case-matched trauma patients 10 years or younger. Two cohorts were identified cohort A where C-spine imaging was performed and cohort B where no imaging was conducted. The CCR and NLC criteria were then applied retrospectively to each cohort. Results: Cohort A contained 125 cases and cohort B with 250 cases. Seven patients (3%) had significant C-spine injuries. In cohort A, NLC criteria could be applied in 108 (86.4%) of 125 and CCR in 109 (87.2%) of 125. National Emergency X-Radiography Utilization Low-Risk Criteria suggested that 70 (58.3%) cases required C-spine imaging compared to 93 (76.2%) by CCR. National Emergency X-Radiography Utilization Low-Risk Criteria missed 3 C-spine injuries, and CCR missed one. In cohort B, NLC criteria could be applied in 132 (88%) of 150 and CCR in 131 (87.3%) of 150. The NLC criteria identified 8 cases and CCR identified 13 cases that would need C-spine radiographs. Fisher's 2-sided Exact test demonstrated that CCR and NLC predictions were significantly different (P =.002) in both cohorts. The sensitivity of CCR was 86% and specificity was 94%, and the NLC had a sensitivity of 43% and a specificity of 96%. Conclusions: Although CCR and NLC criteria may reduce the need for C-spine imaging in children 10 years and younger; they are not sensitive or specific enough to be used as currently designed Elsevier Inc. All rights reserved. Presented at the 40th Annual CAPS Meeting, August 21-24, 2008, Toronto, Ontario, Canada. Corresponding author. Section of Pediatric Surgery, University of Michigan Hospitals, Ann Arbor, MI 48109, USA. Tel.: ; fax: address: pehrlich@med.umich.edu (P.F. Ehrlich). Cervical spine injuries (CSIs) remain one of the most devastating consequences from trauma. An injury can result in lifelong morbidity. Therefore, a thorough evaluation is mandated when a spinal cord injury is suggested or suspected. Alternatively, CSIs are rare events, especially in pediatric trauma (1%-2%), and often many children undergo cervical spine imaging who may not need it [1-5]. This is further complicated by concerns regarding the routine use of /$ see front matter 2009 Elsevier Inc. All rights reserved. doi: /j.jpedsurg

2 988 P.F. Ehrlich et al. computed tomographic (CT) scanning of the cervical spine in pediatric patients because of excess radiation, the low incidence of CSIs, and increased costs. Clinical decision rules (CDRs) are developed to reduce the uncertainty of medical decision making by standardizing the collection and interpretation of clinical data [6-8]. A decision rule is derived from original research and may be defined as a decision-making tool that incorporates 3 or more variables from the history, physical examination, or simple tests [6-8]. The Canadian C-spine (cervical spine) Rule (CCR) and the National Emergency X-Radiography Utilization Low- Risk Criteria (NLC) are decision rules designed to guide C- spine radiography in trauma patients [9-11]. National Emergency X-Radiography Utilization low-risk criteria was first described in 1992 [11]. A validation study involving 34,069 patients reported a sensitivity of 99.6% and a specificity of 12.9% for CSI [9]. In this validation study, however, only 2.5% of the participants were children younger than 10 years, and only 0.08% had a CSI [9,12]. The CCR studied 8924 patients and reported a sensitivity of 100% (95% confidence interval, 98%-100%) and 42.5% specificity (95% confidence interval, 40%-44%) for identifying 151 clinically important CSIs [10]. No children younger than 16 were included in this study. Both the NLC and the CCR studies concluded that their rules had the potential to significantly reduce practice variation and inefficiency in emergency department use of C-spine radiography. The evaluation of the cervical spine in a young (b10) trauma patient is challenging. Young children may not be able to communicate crucial symptoms; the physical examination can be compromised in an anxious crying or uncooperative child. There are also recognized anatomical differences between pediatric and adult cervical spines [13-15]. Therefore, the presentation of a CSI in an adult is not necessarily the same as a child. Thus, clinical decisions rules for cervical spine imaging derived from adult studies may not be as sensitive or specific in a young pediatric population. In 2003, a study compared the NLC and CCR decisions rules and suggested that CCR may be superior to NLC in reducing the rates of unnecessary C-spine imaging because of a higher sensitivity and specificity for detecting clinical significant spine injuries [16]. It is unclear how the 2 decision rules compare with young children. The purpose of this case-matched study was to examine the performance of the decision rules in a pediatric trauma population younger than 10 years. Our working hypothesis is that NLC and the CCR are effective decision rules in determining the necessity of cervical spine imaging for pediatric trauma patients 10 years and younger. 1. Methods This study was approved by the University of Michigan's Institutional Review Board (Ann Arbor, Mich). It is a retrospective case-matched design with trauma patients 10 years or younger. The University of Michigan CS Mott Children's Hospital is an American College of Surgeonsverified level I pediatric trauma center. The pediatric trauma registry from 2005 to 2007 was used to identify the patients. The pediatric trauma registry records all hospital trauma patients younger than 18 years Cervical spine imaging Our institutional guidelines suggest an initial physical examination of the C-spine for all trauma patients. There were no protocols or other CDR being used for cervical spine examination. Patients with reliable examinations and who were fully awake without motor/sensory deficits, neck pain, evidence of intoxicating agents, and distracting injuries were clinically cleared in the trauma center by an Advanced Trauma Life Support-certified physician. No further evaluation of the cervical spine was performed after the stabilization collar was removed. If the patient complained of neck tenderness, had neurologic deficits, had an abnormal Glasgow Coma Scale (GCS) (because of head injury, drugs, alcohol), or distracting pain from another injury, the patient underwent cervical spine imaging. Plain C-spine radiographs, CT scan, or both were used, and the decision for investigation was made by the designated leader of the trauma team. If the radiographic imaging was negative for CSI, the initial stabilization collar was changed to a padded collar until a reliable examination could be performed. Flexion and extension views were performed in patients with continued cervical tenderness or if they required prolonged intubation. If pain persisted, patients were discharged home with a cervical spine collar and followed by the neurosurgery team for clearance. The ultimate decision to image the cervical spine was at the discretion of the trauma team leader. Trauma team leaders could be one of the following: a pediatric surgeon or fellow, an emergency department faculty or fellow, or the senior resident (level 4) in general surgery Clinical decision criteria The CCR criteria and NLC criteria are shown in Table 1. A positive answer to any of the 3 CCR criteria or 1 of the 5 NLC criteria mandated cervical spine imaging Study cohorts The study population of interest was the pediatric trauma patient 10 years or younger. Two study cohorts were identified. Cohort A included all the trauma patients 10 years or younger who underwent C-spine imaging as part of their initial workup in the emergency department. Cohort B included trauma patients 10 years or younger who

3 CCR and NLC for C spine radiography in young trauma patients 989 Table 1 Comparison of the NLC and the CCR criteria for C-spine radiography Crit. # NEXUS/NLC CCR 1 Posterior midline tenderness? Was there a dangerous mechanism of injury? (ie, fall N3 ft, MVC involving rollover or ejection) 2 Intoxication involved? Midline neck tenderness? 3 Is the patient alert? (GCS b15) 4 Focal neurologic deficit? 5 Painful, distracting injuries? did not undergo C-spine imaging as part of their initial workup in the emergency department. This cohort was randomly identified by the trauma registry. After this, the CCR and NLC criteria were then applied to each cohort based on the initial history and physical examination using 2 blinded and trained research assistants (RAs) Research assistants Research assistants (RAs) were undergraduate science and/or medical students at the University of Michigan. Research assistants were trained by the study principal investigator to review charts and identify the CCR and NLC criteria from the medical record. A β sample of 20 patients per RA was then reviewed by the principal investigator to ensure reliability and validity of the RA interpretation. The patients were then reentered into each cohort. Study patients were reviewed twice (once by each RA) in a blinded fashion. If there was discrepancy between the 2 RA interpretations or if there was a question about a particular study patient, the principle investigator reviewed the case and made a final determination Research outcomes Unable to rotate neck safely to 45? NEXUS indicates National Emergency X-Radiography Utilization Study; MVC, motor vehicle crash. Research outcomes included missed injuries, the ability to apply the CCR or NLC criteria, and reduction or increased requirements for decision rules per cohort. In addition, age, sex, Injury Severity Score, GCS, intubation status, and treatment plan were analyzed. A clinically important spine injury was defined as any fracture, dislocation, or ligamentous instability demonstrated by imaging. Clinically unimportant findings included osteophyte avulsion, a transverse process not involving the facet joint, a spinous process not involving the lamina, or a simple vertebral compression of less than 25% of body height. This definition has been used and standardized in previous studies [17]. 2. Results Between 2005 and 2007, 1307 pediatric trauma patients were identified for review. For 318 patients (24.3%), radiographic imaging was performed to rule out a possible CSI. Of these, 125 were 10 years or younger and comprised cohort A. Nine hundred eighty-nine patients did not undergo cervical spine imaging of which 150 children 10 years or younger were randomly identified from the trauma registry. This comprised cohort B. Injury characteristics are shown in Table 2. Seven patients (3%) had clinically significant CSIs all of whom underwent C-spine imaging (cohort A) as determined by the trauma team leader. Cohort A (imaged) contained 72 males and 53 females with an average age of 4.3 ± 3.1 years. Cohort B (nonimaged) contained 88 males and 62 females with an average age of 5 ± 2.6 years. As expected, the Injury Severity Score and GCS were significantly different between the 2 cohorts. Posterior midline tenderness (NLC1) and ability to rotate the neck (CCR3) were the most frequent criteria that could not be evaluated. In cohort A, NLC criteria could be applied in 108 (86.4%) of 125 patients, whereas CCR criteria could be applied in 109 (87.2%) of 125. National Emergency X-Radiography Utilization Low-Risk Criteria suggested that only 70 (58.3%) cases required C-spine imaging compared to 93 (76.2%) by CCR. A 2-sided Fisher's Exact test demonstrated that the CCR and NLC predictions were significantly different (P =.002). If applied, NLC would have missed 3 CSIs (fractures of C3, C5, and C7), whereas CCR would have missed one (spinous fracture of C5). The sensitivity and specificity of CCR were 86% and 94%, respectively, whereas the NLC had a sensitivity of 43% and a specificity of 96%. In cohort B, the NLC criteria could be applied to 132 (88%) of 150 patients, and the CCR criteria could be applied to 131 (87.3%) of 150 patients. If applied, NLC and CCR criteria identified 8 and 13 cases, respectively, that would have needed C-spine radiographs. Only 4 cases were common to both groups. A 2-sided Fisher's Exact test showed that NLC and CCR were different (P =.003). There were no missed injuries. Table 2 Comparison of patient demographics between cohort A and B Variable Cohort A (imaged) Cohort B (not imaged) Age 4.3 ± ± 2.6 GCS 13.1 ± ± 0.2 ISS 13.3 ± ± 6.0 Sex Male = 72 Male = 88 Female = 53 Female = 62 Missed injuries NLC = 3 NLC = 0 CCR = 1 CCR = 0 ISS indicates Injury Severity Score.

4 990 P.F. Ehrlich et al. 3. Discussion Clinical decision rules help clinicians make diagnostic and therapeutic decisions at the bedside. They are derived from original research and incorporate 3 or more variables from the history, examination, or simple tests [6-8]. Clinical decision rules have been developed for ankle injuries, deep vein thrombosis, and for patients who have pneumonia [6,7,18-21]. There are 3 stages in developing a CDR. The first stage is to create/derive the rule; the second stage involves validation of the rule to assess the rule's accuracy, reliability, and potential impact; and the third stage is to assess the rule's impact on patient care and outcomes. Cervical spine injuries after pediatric trauma are rare (1%) [1,2]. The NLC and CCR are 2 CDRs developed to assist with cervical spine imaging after a trauma. Their goals are 2- fold identify patients at risk for a CSI and reduce unnecessary imaging. Cervical spine imaging after a trauma is important because missing an injury is potentially devastating. However, unnecessary imaging increases costs and, with the increased use of CT for CSIs, may expose patients to excess radiation [22]. This is particularly important for children [23,24]. The NLC criteria were developed and then validated in a mixed population of adults and children; however, only 9% of the patients were considered pediatric. Furthermore, intoxication is not a relevant issue in young children, and no special considerations were used for nonverbal children. A secondary analysis of the pediatric cases was performed, and although the NLC criteria were performed well, there were several concerns raised by the authors [12]. Although no CSI were missed and the sensitivity of the decision rule was 100%, the confidence intervals were wide, ranging from 87.8% to 100%. Furthermore, there were only 30 children with CSIs in this series, and all injuries were located between C5 through C7. This does not reflect true injury patterns. A recent publication from Garton et al [25] with 187 pediatric CSIs demonstrated that younger children tended to have higher level injuries at C1 through C3, whereas older children had injuries at C5 through C7. This finding suggests that the age range for the pediatric sample size was insufficient in the NLC study. Despite the sensitivity and that NLC might reduce excess imaging, the authors concluded that the study did not prove that the NLC criteria could be applied safely to children. The CCR rule was not specifically developed to be used in the pediatric population nor was it validated with a pediatric trauma sample. Yet, when the CCR and NLC were compared, the CCR performed better. However, the youngest patients in the sample population were 16 years of age [16]. Our study hypothesis was that the NLC and the CCR were effective decision rules in determining the necessity of cervical spine imaging for pediatric trauma patients 10 years and younger. Based on this sample population, the data do not support the hypothesis. We chose children younger than 10 years because we wanted to focus on patients who had not started puberty. The anatomical differences between the pediatric and adult cervical spine remain prominent until the age of 8 and may persist until 12 years [13-15,26]. We recognize that if we had limited our sample to patients aged 8 years or younger, the sensitivity and specificity of each CDR may have changed, but we do not think it would have changed our conclusions substantially. Therefore, as currently defined, we cannot endorse using either the CCR or the NLC in children 10 or younger. In cohort A, both CDRs suggested that imaging could be reduced. Indeed, the NLC would have reduced imaging by 42% and CCR by 24%. However, although the NLC criteria would have reduced imaging it would have missed 3 clinically significant CSIs, whereas the CCR would have missed one. Although a goal of a CDR is to reduce unnecessary medical investigations, the sensitivity of each decision rule in this study population was unacceptably low. Garton et al [25] had a similar finding in their study in which the NLC had a sensitivity of 75%. Although the CCR performed better than NLC in this study because of the inherent rarity of CSI, a single injury would have dramatically affected sensitivity of each CDR. An important aspect of a CDR to consider is whether one can apply the criteria to a specific patient population. When the NLC was compared to the CCR, 10% of patients were excluded because all criteria could not be fully evaluated [16]. In this study, a similar observation was noted. The respective criteria of each CDR could not be applied in every case (NLC, 86.4%; CCR, 87.2%). Posterior midline tenderness (NLC1) and the ability to rotate the neck (CCR3) were the most frequent criteria that could not be evaluated. This may be because physicians may not be comfortable assessing the range of motion (CCR3) and midline tenderness (NLC1) in children wearing a collar. Alternatively, this study was a retrospective, and although in some cases where the CDR criteria could not be applied was because examination was not performed, it could also have been performed but simply not documented. The cases in cohort A that the CCR and NLC determined did not require imaging were not the same. In cohort B, the CCR determined that 13 patients required imaging, whereas the NLC found 8. Only 4 cases were common to both. This observation that both the CCR and NLC performed differently should not be surprising because the CDRs only share one clinical component. The limitations of this study are inherent in its design. This is a retrospective study based on chart reviews. A prospective study where the criteria are assessed at the same time as the physician determines the need for cervical spine imaging may produce different result. Although the RAs were trained to apply CDR criteria, they were not medical doctors [27]. In summary, neither CDR performed at a high enough level to be used with confidence. Intuitively, this is not surprising because neither CDR was designed to account for pediatric issues. Both CDRs were more sensitive and specific

5 CCR and NLC for C spine radiography in young trauma patients 991 with the adolescent population and may be a useful tool in this group as they account for a significant proportion of pediatric trauma patients. Furthermore, it is a compelling argument to use CDR to improve the efficiency of cervical spine imaging. Both of these CDR have criteria that are relevant, but age adjustments need to be evaluated to ensure a higher sensitivity and specificity for younger children. Future research should focus on identifying the most robust criteria as well as developing new criteria designed specifically for younger children. References [1] Kokoska ER, Keller MS, Rallo MC, et al. Characteristics of pediatric cervical spine injuries. J Pediatric Surg 2001;36: [2] Brown RL, Brunn MA, Garcia VF. Cervical spine injuries in children: a review of 103 patients treated consecutively at a level I pediatric trauma center. J Pediatric Surg 2001;36: [3] McCaig LF, Ly N. National Hospital Ambulatory Medical Care Survey: 2000 Advance data from vital statistics. National Center for Health Statistics Hyattsville (Md): National Center for Health Statistics; 2002 [DHHS publication no (PHS) ]. [4] Roberge RJ. Facilitating cervical spine radiography in blunt trauma. Emerg Med Clin North Am 1991;9: [5] Daffner RH. Cervical radiography in the emergency department: who when how extensive? J Pediatric Surg 1993;11: [6] Laupacis A, Stiell IG, Sekar N. Clinical prediction rules: a review and suggested modifications of methodological standards. JAMA 1997; 277: [Abstract]. [7] McGinn TG, Guyatt GH, Wyer PC, et al. Users' guides to the medical literature: XXII: how to use articles about clinical decision rules. Evidence-Based Medicine Working Group. JAMA 2000;284: [8] Stiell IG, Wells GA. Methodologic standards for the development of clinical decision rules in emergency. Ann Emerg Med 1998;33: [9] Hoffman JR, Mower WR, Wolfson AB, et al. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. N Engl J Med 2000;343:99. [10] Stiell IG, Wells GA, Vandemheen KL, et al. The Canadian C-spine rule for radiography in alert and stable trauma patients. JAMA 2001;286: [11] Hoffman JR, Schriger DL, Mower W, et al. Low-risk criteria for cervical spine radiography in blunt trauma: a prospective study. Ann Emerg Med 1992;21: [12] Viccellio P, Simon H, Pressman BD, et al. A Prospective Multicenter Study of cervical spine injury in children. Pediatrics 2001;108:e20. [13] Swiskchuk L. Anterior displacement of C2 in children: physiologic or pathologic? Radiology 1977;122: [14] Swiskchuk L. The cervical spine in childhood. Curr Probl Diagn Radiolol 1984;13:1-26. [15] Cattel HS, Filtzer DL. Pseudosubluxation and other normal variations of the cervical spine in children. J Bone Joint Surg 1964;47A: [16] Stiell IG, Clement CM, Mcknight RD. The Canadian C-Spine Rule versus the NEXUS low-risk criteria in patients with trauma. N Engl J Med 2003;349: [17] Stiell IG, Lesiuk HJ, Vandemheen KL, et al. Obtaining a consensus for a definition of clinically important cervical spine injury in the CCC Study. Acad Emerg Med 1999;6:435 [Abstract]. [18] Stiell IG, Wells GA, Vandemheen KL, et al. The Canadian CT head rule for patients with minor head injury. Lancet 2001;357: [19] Stiell IG, Wells GA, Vandemheen KL, et al. Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries. JAMA 1997;278: [20] Stiell IG, Greenberg GH, Mcknight RD, et al. Decision rules for the use of radiography in acute ankle injuries :refinement and prospective validation. JAMA 1993;269: [21] Wells PS, Owen C, Doucette. Does this patient have a deep vein thrombosis. JAMA 2006;295: [22] National Cancer Institute. Radiation risks and pediatric computed tomography (CT): a guide for health care providers. National Cancer Institute; radiation-risks-pediatric-ct. [23] Panacek EA, Mower WR, Holmes JF, et al. Test performance of the individual NEXUS low -risk clinical screening criteria for cervical spine injury. Ann Emerg Med 2001;38:22-5. [24] Paterson A, Frush DP, Donnelly LF. Helical CT of the body: are settings adjusted for pediatric patients? AJR Am J Roentgenol 2001; 176: [25] Garton HJ, Hammer MR. Detection of pediatric cervical spine injury. Neurosurgery; 2008;62: [26] Fesmire FM, Luten RC. The pediatric cervical spine: developmental anatomy and clinical aspects. J Emerg Med 1989;7: [27] Mahadevan S, Mower W, Hoffman JR, et al. Interrater reliability of cervical spine injury criteria in patients with blunt trauma. Ann Emerg Med 1998;31: