951 C OPYRIGHT Ó 2014
BY
T HE J OURNAL
OF
B ONE
AND J OINT
S URGERY, I NCORPORATED
Does CT Angiography Matter for Patients with Cervical Spine Injuries? John C. Hagedorn II, MD, Sanford E. Emery, MD, MBA, John C. France, MD, and Scott D. Daffner, MD Investigation performed at the Department of Orthopaedics, West Virginia University, Morgantown, West Virginia
Background: Cervical injury can be associated with vertebral artery injury. This study was performed to determine the impact of computed tomography (CT) angiography of the head and neck on planning treatment of cervical spine fracture, if these tests were ordered appropriately, and to estimate cost and associated exposure to radiation and contrast medium. Methods: This retrospective review included all patients who underwent CT of the cervical spine and CT angiography of the head and neck from January 2010 to August 2011 at one institution. Patients were divided into those with and those without cervical spine fracture seen on CT of the cervical spine. We determined if the CT angiography of the head and neck was positive for vascular injury in the patients with a cervical fracture. Vascular injury treatment and alterations in surgical fracture treatment due to positive CT angiography of the head and neck were recorded. A scan was deemed appropriate if it had been ordered per established institutional protocol. Results: Of the 381 patients who underwent CT angiography of the head and neck, 126 had a cervical injury. Sixteen of the CT angiography studies were appropriately ordered for non-spinal indications, and twenty-three were inappropriately ordered. The CT angiography was positive for one patient for whom the imaging was off protocol and one for whom the indication was non-spinal. Nineteen patients had positive CT angiography of the head and neck; no patient underwent surgical intervention for a vascular lesion. Eleven patients underwent surgical intervention for a cervical fracture; the operative plan was changed because of vascular injury in one case. The CT angiography was positive for eleven of fortyeight patients who had sustained a C2 fracture; this group accounted for eleven of the nineteen positive CT angiography studies. Noncontiguous injuries occurred in nineteen patients; three had positive CT angiography of the head and neck. The approximate charge for the CT angiography was $3925, radiation exposure was approximately 4000 mGy/cm, and contrast-medium load was approximately 100 mL. Conclusions: Positive CT angiography of the head and neck rarely altered surgical treatment of cervical spine injuries. This study supports the findings in the literature that C1-C3 spine injuries have an increased association with vertebral artery injury. CT angiography of the head and neck ordered off protocol had a low likelihood of being positive. Strict adherence to protocols for CT angiography of the head and neck can reduce costs and decrease unnecessary exposure to radiation and contrast medium. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
I
n the first few minutes of caring for a trauma patient, many injuries are obvious or quickly become apparent. One injury that is often not obvious in the acute setting is blunt
injury to the vertebral artery. Identification of these injuries, however, is imperative to ensure that consequences such as stroke, loss of posterior circulation to the brain, and neurologic
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, one or more of the authors has had another relationship, or has engaged in another activity, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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sequelae do not develop. Without screening, many of these injuries are missed until devastating consequences of the injury present1,2. In contrast to traumatic injuries that necessitate surgical intervention, the consequences of vertebral artery injury often can be avoided through anticoagulation and antiplatelet therapy1. To aid the physician caring for a trauma patient, criteria have been established to screen for vertebral artery injuries with computed tomography (CT) angiography of the head and neck1,2 and treat those injuries. These criteria not only help identify injuries to the vertebral artery, but also help direct utilization of CT angiography of the head and neck, which has its own risks such as possible acute kidney injury from contrast medium and radiation-induced malignancy 3-6. Vertebral artery injury is a comorbidity of cervical spine fractures; certain fractures, such as those involving C1, C2, or C3, are associated with a high rate of vertebral artery injury7-9. Recently, Even et al. reported no difference in rates of vertebral artery injury between upper (occiput to C2) and subaxial cervical fractures, or fractures involving the transverse foramen, but found a significantly increased rate with displaced fractures and in patients presenting with a neurologic deficit10. Early detection of vertebral artery injuries with cervical fractures is important so that anticoagulation treatment can be initiated and coordinated with surgical timing. Less clear is whether the findings of CT angiography of the head and neck alter the treatment of the cervical spine fracture and whether the study is required for preoperative planning. Several investigators have evaluated the likelihood of associated vertebral artery injury with certain fracture patterns, but we are unaware of any studies that have specifically assessed the appropriate utilization of imaging protocols for CT angiography of the head and neck, the impact of positive findings on surgical and medical management, and the costs and risks associated with inappropriately ordered studies. The purpose of the present study was to evaluate the utilization of CT angiography of the head and neck at a level-I trauma center as well as to determine how frequently imaging protocol was followed, the results of those studies, the impact of the CT angiography findings on treatment of cervical fractures, and the potential implications of inappropriately ordered studies.
D O E S CT A N G I O G R A P H Y M AT T E R CERVICAL SPINE INJURIES?
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TABLE I Criteria for Ordering CT Angiography of the Head and Neck* Unexplained or incongruous central or lateralizing neurologic deficit Evidence of acute cerebral infarct on CT scan of head: activate stroke team Glasgow Coma Scale score £8 Evidence of diffuse axonal injury Facial fracture or Le Fort type-II or III fracture Basal skull fracture Petrous fracture Complex mandible fracture d
d
d
Cervical spine fracture or subluxation C1, C2, or C3 fracture Extension of fracture through transverse foramen d
d
Cervical spinal cord injury Hanging injuries Major thoracic injury or first-rib fracture Thoracic aorta or major vessel injury Sternal fracture Scapular fracture d
d
d
*Only one criterion must be present to order CT angiography of the head and neck. 1,2
literature and previously established protocols . We assessed cost to the patient by abstracting the charge for the CPT for the CT angiography of the head and neck from the billing record. Radiation exposure and contrast-medium load vary by patient; the CT angiography of the head and neck was performed on an Aquilion 64 slice scanner (Toshiba America Medical Systems, Tustin, California), which automatically determines radiation dose on the basis of patient size. Contrastmedium load varies according to patient body mass. The clinical outcome was assessed by a review of the patient’s medical records at the time of the most recent follow-up.
Statistical Methods
Materials and Methods
The significance of the difference between the number of positive CT angiography studies when the tests were appropriate (for cervical or non-cervical indications) and the number when they were not appropriate was determined with the chi-square test. This statistical calculation was carried out with use of Minitab (Minitab, State College, Pennsylvania) with significance set at p < 0.05.
T
Source of Funding
his study was approved by our institutional review board. A retrospective review of the records of all patients who underwent CTof the cervical spine and CT angiography of the head and neck from January 2010 to August 2011 at our level-I trauma center was conducted by abstracting charts for the Current Procedural Terminology (CPT) codes for CT of the cervical spine and CT angi11 ography of the head and neck (CPT 72125-72127 and 70496 or 70498) . Patients were divided in two groups: those with cervical spine fracture and those without such a fracture. In the cervical spine fracture group, several data points were abstracted: location of the fracture, presence of vertebral artery injury, surgical or nonsurgical treatment of the vertebral artery injury, alteration of treatment (specifically, surgical planning), and any neurologic or cerebrovascular compromise at the time of the most recent follow-up. In the group without a cervical spine fracture, for whom the study was ordered for indications other than cervical trauma, we noted whether the CTangiography of the head and neck was positive for vertebral artery injury. We also evaluated appropriate utilization on the basis of whether our current institutional imaging protocol for CT angiography of the head and neck was used (Table I). This protocol was established on the basis of current
No external funding was received in support of this study.
Results hree hundred and eighty-one patients had a CT of the cervical spine and CT angiography of the head and neck per institutional protocols. One hundred and twenty-six of these patients had cervical spine fracture, and nineteen (15%) of the 126 had vertebral artery injury identified on the CTangiography. All vertebral artery injuries were unilateral, and none of the patients required interventional treatment of the vascular lesion. Anticoagulation was started for sixteen patients, two were not given anticoagulation because of contraindications, and one was not treated because she died from the traumatic injuries. Of the
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TABLE II Number of CT Angiography Studies of the Head and Neck Ordered and Number Positive per Indication in Cervical Fracture Group (N = 126) No. (%) Ordered
No. (%) Positive
Cervical
87 (69%)
17 (20%)
Non-cervical
16 (13%)
1 (6%)
Not indicated per protocol
23 (18%)
1 (4%)
Indication
sixteen patients treated with anticoagulation, twelve took 325 mg of aspirin twice daily or 81 mg daily, one received 40 mg of enoxaparin twice daily, and three were therapeutically treated with warfarin anticoagulation. No complications from anticoagulation were reported. Eleven of the nineteen patients with vertebral artery injury underwent a surgical procedure for the cervical spine fracture, including seven who were treated with a posterior cervical approach; one surgeon elected not to expose the cervical spine on the side without vertebral artery injury to obviate potential injury to the intact vertebral artery. The average duration of follow-up was 152 days (range, seventeen to 777 days). Regardless of whether they underwent surgical or nonsurgical treatment of the cervical fracture, all patients with vertebral artery injury were reported to be neurologically intact without evidence of sequelae from the cerebrovascular injury at the most recent follow-up evaluation. Fractures with associated vertebral artery injury most commonly involved C2 (eleven of the nineteen fractures). Overall, eleven (23%) of forty-eight patients with a C2 fracture had CT angiography that was positive for a vertebral artery injury. Five of the nineteen patients with a vertebral artery injury had a fracture that did not involve C1, C2, or C3, and three of these nineteen patients had noncontiguous cervical injuries. Of the 107 cervical fractures without vertebral artery injury, fiftythree (50%) involved C4-C7. Twenty-one patients in this group had CT angiography of the head and neck ordered off protocol. Of the 126 studies ordered for patients with cervical spine fracture, sixteen were ordered per protocol for a noncervical-spine indication and one of the sixteen was positive for vertebral artery injury. Twenty-three studies in the cervical fracture group were ordered off protocol (for example, for a spinous process fracture not at C1, C2, or C3), and one (4%) of them was positive for vertebral artery injury. The remaining eighty-seven studies were ordered for cervical spine indications per protocol, and seventeen (20%) were positive (Table II). There was no significant difference in the prevalence of positive CT angiography findings between the studies ordered for cervical spine indications and those ordered off protocol (p = 0.113), or between all studies ordered per protocol (for cervical or non-cervical indications) and those ordered off protocol (p = 0.194). There was also no significant difference between studies ordered per protocol for cervical indications and those ordered per protocol for non-cervical indications (p = 0.293), or between studies ordered for cervical indications and those ordered for non-cervical indica-
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tions or off protocol (p = 0.057). Of the 255 patients who did not have a cervical fracture, twenty-four (9.4%) had a CT angiography study of the head and neck that was positive for vertebral artery injury. The billed charge for CT angiography of the head and neck was $3925. The total charge for the twenty-three patients in the fracture group for whom the study was ordered off protocol was $90,275. Although it varies by patient according to body habitus and autocalibration by the scanner, radiation exposure was approximated at 4000 mGy/cm. Thus, in addition to the unwarranted cost for the twenty-three patients for whom the study was ordered off protocol, there was also approximately 92,000 mGy/cm of radiation exposure for all of those patients combined. Contrast-medium load was approximately 100 mL, depending on patient size. There were no reported episodes of anaphylactic reaction to contrast medium or associated nephropathy in the patients in our study. Discussion creening for vertebral artery injury in trauma patients is important because such injuries can be associated with substantial morbidity and mortality if not identified and treated appropriately1,2. Authors of previous studies have attempted to elucidate injury patterns likely to be associated with vertebral artery injury, which has led to the development of protocols for performing CT angiography of the head and neck7-10. The aim of our study was to determine if such tests were utilized appropriately per institutional protocol, if the tests had an effect on treatment of patients with cervical injuries, and the consequences of the findings of these tests. At our institution, the patient charge for a CT angiography of the head and neck was $3925. The studies that were performed off protocol in our series accounted for more than $90,000 in additional expenses over a twenty-month period. Inappropriately ordered tests place an undue burden on the health-care system, and particularly on uninsured or underinsured patients. These studies are not benign. One consequence of CT angiography of the head and neck is exposure to intravenous contrast medium, which can lead to contrast nephropathy in 5% to 38% of patients, depending on other risk factors that may be unknown in obtunded trauma patients such as diabetes or renal failure5. Trauma patients frequently have multiple CT scans and multiple contrast-medium loads as part of the initial evaluation. In addition, they are often hypovolemic on admission, which can increase the risk of contrast nephropathy. Allergic reaction to contrast medium is another concern. Although anaphylaxis has been reported in only 0.1% of patients exposed to contrast medium, any allergic reaction—particularly in a critically ill trauma patient—could have devastating consequences6. In our study population, no patient experienced contrast-medium-related complications. Radiation also poses a substantial risk to patients undergoing CT angiography of the head and neck. The medical literature raises specific concerns about the age at which a patient is exposed to radiation and the amount of radiation
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received. Younger patients have an increased lifetime risk of radiation-induced sarcoma from just one sixty-four-slice coronary angiogram; for example, Huda et al. reported that, for a twenty-year-old woman, such a study leads to a lifetime cancer risk of one in 143, whereas that risk is one in 466 for a sixty-year-old4. Also, long-term follow-up of Japanese patients who survived the atomic bomb blasts has shown that the acute amount of radiation needed to develop a sarcoma in a lifetime is much less than previously documented3. This observation is especially concerning for trauma patients who are often younger and subjected to multiple scans. To our knowledge, no one has calculated the lifetime cancer risk for patients exposed to CT angiography of the head and neck. One way to reduce the risk to patients is by monitoring correct utilization of the tests by developing protocols1,2. The majority of the studies performed in our population were ordered per established institutional protocol either for an indicated cervical fracture pattern (eighty-seven patients; 69%) or other indicated traumatic injuries (sixteen patients; 13%). However, 18% (twenty-three) of the 126 CT angiography studies of the head and neck were ordered and performed for fracture patterns that were not indications per institutional protocol. This exposure to risk did not lead to identification of large numbers of silent vertebral artery injuries as only one (4%) of the studies ordered off protocol was positive. Even the tests ordered per protocol for non-cervical-fracture indications had a low likelihood of being positive. This finding suggests that, in the absence of cervical pathology, the likelihood of vertebral artery injury is low and protocols should be strictly followed to ensure proper utilization of these scans. Seventeen (20%) of the studies ordered for patients with cervical fracture were positive for a vertebral artery injury. This percentage is much higher than that for the studies ordered per protocol for non-cervical injuries and those ordered off protocol, suggesting a benefit in utilizing this modality. However, our data failed to demonstrate that the criteria used for ordering these scans led to a significant difference with regard to the ability to identify vertebral artery injuries. Although our data showed a consistent trend toward an increased prevalence of vertebral artery injury when the study had been ordered for an appropriate cervical fracture, this prevalence was not significantly different from that found with studies ordered for noncervical-fracture indications or those ordered entirely off protocol. Previous authors have reported a high correlation of vertebral artery injuries in the presence of upper cervical (C1C3) fractures, and criteria for imaging protocols have been based on these studies7-9. In the present study, the fracture location most frequently associated with a vertebral artery injury was C2, with almost one in four C2 fractures (eleven patients; 23%) having a positive finding on CT angiography of the head and neck. These eleven C2 fractures accounted for more than half of all positive CT angiography studies of the head and neck in this population. Recent data have raised questions about the traditionally accepted high-risk categories of upper cervical fractures and fractures involving the transverse foramen, and have suggested that vertebral artery injuries are more common
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in association with displaced cervical injuries and among patients presenting with neurologic deficits10. In the present study, all patients were reported to be neurologically intact without evidence of cerebrovascular complications at the time of the most recent follow-up, regardless of the treatment they had received for either the cervical spine fracture or the vertebral artery injury. All vertebral artery injuries were treated pharmacologically, which is consistent with other studies10. Our study had limitations. Certain individuals may have sustained fatal injuries involving the vertebral artery and died before reaching the trauma center. Our search would not have identified such patients. Although the purpose of the study was to evaluate the impact of CT angiography of the head and neck on patients presenting to our trauma center, this possibility also underscores the importance of early imaging of survivors who are at risk. In addition, as this was a retrospective study, it was not possible to standardize treatment of either the vertebral artery injury or the cervical fracture. Our assessment of medical decision-making, particularly with regard to surgical planning, was based on a review of the medical records. It is possible that some surgeons chose nonoperative treatment for the fracture because of the vertebral artery injury but that information was not specified in their notes. Also, because this was a retrospective study, we could not specifically follow laboratory results indicative of renal injury unless they had been ordered. Similarly, we could not track the exact radiation exposure of our patients. Nevertheless, we believe that our estimates of exposure, based on scanner-specific properties, are reasonably accurate. As to whether or not CT angiography of the head and neck matters for patients with cervical spine injury, the answer depends on the reason for the study. Our data indicate that CTangiography of the head and neck is an important screening tool that, if utilized appropriately, can detect vertebral artery injuries, allowing early initiation of pharmacologic treatment. On the other hand, it had little impact on decision-making for operative treatment of cervical fractures, and ‘‘routine’’ CT angiography of the head and neck for ‘‘surgical planning’’ is discouraged. Vertebral artery injuries can be devastating if not diagnosed and treated. Screening examinations, especially in the setting of cervical trauma, are necessary to ensure that a major injury is not missed. We recommend strict adherence to established imaging protocols to ensure that studies are ordered appropriately to minimize the risks and costs associated with unnecessary studies. n
John C. Hagedorn II, MD Sanford E. Emery, MD, MBA John C. France, MD Scott D. Daffner, MD Department of Orthopaedics, West Virginia University, P.O. Box 9196, Morgantown, WV 26506-9196. E-mail address for J.C. Hagedorn II: [email protected]
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References 1. Bromberg WJ, Collier BC, Diebel LN, Dwyer KM, Holevar MR, Jacobs DG, Kurek SJ, Schreiber MA, Shapiro ML, Vogel TR. Blunt cerebrovascular injury practice management guidelines: the Eastern Association for the Surgery of Trauma. J Trauma. 2010 Feb;68(2):471-7. 2. Western Trauma Association. Blunt cerebralvascular injury algorithm. Western Trauma Association 2002-2011. 1 Apr. 2012. http://westerntrauma.org/algorithms/ ScreeningForAndTreatmentOfBluntCerebrovascularInjuries/References.html. Accessed 2013 Dec 17. 3. Samartzis D, Nishi N, Hayashi M, Cologne J, Cullings HM, Kodama K, Miles EF, Funamoto S, Suyama A, Soda M, Kasagi F. Exposure to ionizing radiation and development of bone sarcoma: new insights based on atomic-bomb survivors of Hiroshima and Nagasaki. J Bone Joint Surg Am. 2011 Jun 1;93(11): 1008-15. 4. Huda W, Schoepf UJ, Abro JA, Mah E, Costello P. Radiation-related cancer risks in a clinical patient population undergoing cardiac CT. AJR Am J Roentgenol. 2011 Feb;196(2):W159-65. 5. Trivedi M, Prabhahar T, Preller J. Prevention of contrast induced nephropathy in the critically ill. European Society of Intensive Care Medicine: e-Posters. Vienna 2009.
European Society of Intensive Care Medicine. http://poster-consultation.esicm.org/ ModuleConsultationPoster/posterDetail.aspx?intIdPoster=569. Accessed 2013 Dec 17. 6. Saljoughian M. Intravenous radiocontrast media: a review of allergic reactions. US Pharm. 2012;37(5):HS-14-6. 7. Fassett DR, Dailey AT, Vaccaro AR. Vertebral artery injuries associated with cervical spine injuries: a review of the literature. J Spinal Disord Tech. 2008 Jun;21(4):252-8. 8. Ding T, Maltenfort M, Yang H, Smith HE, Ratliff J, Vaccaro AR, Greg Anderson D, Harrop J. Correlation of C2 fractures and vertebral artery injury. Spine (Phila Pa 1976). 2010 May 20;35(12):E520-4. 9. Oetgen ME, Lawrence BD, Yue JJ. Does the morphology of foramen transversarium fractures predict vertebral artery injuries? Spine (Phila Pa 1976). 2008 Dec 1;33(25): E957-61. 10. Even J, McCullough K, Braly B, Hohl J, Song Y, Lee J, McGirt M, Devin C. Clinical indications for arterial imaging in cervical trauma. Spine (Phila Pa 1976). 2012 Feb 15;37(4):286-91. 11. American Medical Association. CPT 2012 professional edition. Chicago: AMA; 2011.
BY
T HE J OURNAL
OF
B ONE
AND J OINT
S URGERY, I NCORPORATED
Does CT Angiography Matter for Patients with Cervical Spine Injuries? John C. Hagedorn II, MD, Sanford E. Emery, MD, MBA, John C. France, MD, and Scott D. Daffner, MD Investigation performed at the Department of Orthopaedics, West Virginia University, Morgantown, West Virginia
Background: Cervical injury can be associated with vertebral artery injury. This study was performed to determine the impact of computed tomography (CT) angiography of the head and neck on planning treatment of cervical spine fracture, if these tests were ordered appropriately, and to estimate cost and associated exposure to radiation and contrast medium. Methods: This retrospective review included all patients who underwent CT of the cervical spine and CT angiography of the head and neck from January 2010 to August 2011 at one institution. Patients were divided into those with and those without cervical spine fracture seen on CT of the cervical spine. We determined if the CT angiography of the head and neck was positive for vascular injury in the patients with a cervical fracture. Vascular injury treatment and alterations in surgical fracture treatment due to positive CT angiography of the head and neck were recorded. A scan was deemed appropriate if it had been ordered per established institutional protocol. Results: Of the 381 patients who underwent CT angiography of the head and neck, 126 had a cervical injury. Sixteen of the CT angiography studies were appropriately ordered for non-spinal indications, and twenty-three were inappropriately ordered. The CT angiography was positive for one patient for whom the imaging was off protocol and one for whom the indication was non-spinal. Nineteen patients had positive CT angiography of the head and neck; no patient underwent surgical intervention for a vascular lesion. Eleven patients underwent surgical intervention for a cervical fracture; the operative plan was changed because of vascular injury in one case. The CT angiography was positive for eleven of fortyeight patients who had sustained a C2 fracture; this group accounted for eleven of the nineteen positive CT angiography studies. Noncontiguous injuries occurred in nineteen patients; three had positive CT angiography of the head and neck. The approximate charge for the CT angiography was $3925, radiation exposure was approximately 4000 mGy/cm, and contrast-medium load was approximately 100 mL. Conclusions: Positive CT angiography of the head and neck rarely altered surgical treatment of cervical spine injuries. This study supports the findings in the literature that C1-C3 spine injuries have an increased association with vertebral artery injury. CT angiography of the head and neck ordered off protocol had a low likelihood of being positive. Strict adherence to protocols for CT angiography of the head and neck can reduce costs and decrease unnecessary exposure to radiation and contrast medium. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Peer Review: This article was reviewed by the Editor-in-Chief and one Deputy Editor, and it underwent blinded review by two or more outside experts. The Deputy Editor reviewed each revision of the article, and it underwent a final review by the Editor-in-Chief prior to publication. Final corrections and clarifications occurred during one or more exchanges between the author(s) and copyeditors.
I
n the first few minutes of caring for a trauma patient, many injuries are obvious or quickly become apparent. One injury that is often not obvious in the acute setting is blunt
injury to the vertebral artery. Identification of these injuries, however, is imperative to ensure that consequences such as stroke, loss of posterior circulation to the brain, and neurologic
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, one or more of the authors has had another relationship, or has engaged in another activity, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
J Bone Joint Surg Am. 2014;96:951-5
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http://dx.doi.org/10.2106/JBJS.M.00036
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sequelae do not develop. Without screening, many of these injuries are missed until devastating consequences of the injury present1,2. In contrast to traumatic injuries that necessitate surgical intervention, the consequences of vertebral artery injury often can be avoided through anticoagulation and antiplatelet therapy1. To aid the physician caring for a trauma patient, criteria have been established to screen for vertebral artery injuries with computed tomography (CT) angiography of the head and neck1,2 and treat those injuries. These criteria not only help identify injuries to the vertebral artery, but also help direct utilization of CT angiography of the head and neck, which has its own risks such as possible acute kidney injury from contrast medium and radiation-induced malignancy 3-6. Vertebral artery injury is a comorbidity of cervical spine fractures; certain fractures, such as those involving C1, C2, or C3, are associated with a high rate of vertebral artery injury7-9. Recently, Even et al. reported no difference in rates of vertebral artery injury between upper (occiput to C2) and subaxial cervical fractures, or fractures involving the transverse foramen, but found a significantly increased rate with displaced fractures and in patients presenting with a neurologic deficit10. Early detection of vertebral artery injuries with cervical fractures is important so that anticoagulation treatment can be initiated and coordinated with surgical timing. Less clear is whether the findings of CT angiography of the head and neck alter the treatment of the cervical spine fracture and whether the study is required for preoperative planning. Several investigators have evaluated the likelihood of associated vertebral artery injury with certain fracture patterns, but we are unaware of any studies that have specifically assessed the appropriate utilization of imaging protocols for CT angiography of the head and neck, the impact of positive findings on surgical and medical management, and the costs and risks associated with inappropriately ordered studies. The purpose of the present study was to evaluate the utilization of CT angiography of the head and neck at a level-I trauma center as well as to determine how frequently imaging protocol was followed, the results of those studies, the impact of the CT angiography findings on treatment of cervical fractures, and the potential implications of inappropriately ordered studies.
D O E S CT A N G I O G R A P H Y M AT T E R CERVICAL SPINE INJURIES?
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TABLE I Criteria for Ordering CT Angiography of the Head and Neck* Unexplained or incongruous central or lateralizing neurologic deficit Evidence of acute cerebral infarct on CT scan of head: activate stroke team Glasgow Coma Scale score £8 Evidence of diffuse axonal injury Facial fracture or Le Fort type-II or III fracture Basal skull fracture Petrous fracture Complex mandible fracture d
d
d
Cervical spine fracture or subluxation C1, C2, or C3 fracture Extension of fracture through transverse foramen d
d
Cervical spinal cord injury Hanging injuries Major thoracic injury or first-rib fracture Thoracic aorta or major vessel injury Sternal fracture Scapular fracture d
d
d
*Only one criterion must be present to order CT angiography of the head and neck. 1,2
literature and previously established protocols . We assessed cost to the patient by abstracting the charge for the CPT for the CT angiography of the head and neck from the billing record. Radiation exposure and contrast-medium load vary by patient; the CT angiography of the head and neck was performed on an Aquilion 64 slice scanner (Toshiba America Medical Systems, Tustin, California), which automatically determines radiation dose on the basis of patient size. Contrastmedium load varies according to patient body mass. The clinical outcome was assessed by a review of the patient’s medical records at the time of the most recent follow-up.
Statistical Methods
Materials and Methods
The significance of the difference between the number of positive CT angiography studies when the tests were appropriate (for cervical or non-cervical indications) and the number when they were not appropriate was determined with the chi-square test. This statistical calculation was carried out with use of Minitab (Minitab, State College, Pennsylvania) with significance set at p < 0.05.
T
Source of Funding
his study was approved by our institutional review board. A retrospective review of the records of all patients who underwent CTof the cervical spine and CT angiography of the head and neck from January 2010 to August 2011 at our level-I trauma center was conducted by abstracting charts for the Current Procedural Terminology (CPT) codes for CT of the cervical spine and CT angi11 ography of the head and neck (CPT 72125-72127 and 70496 or 70498) . Patients were divided in two groups: those with cervical spine fracture and those without such a fracture. In the cervical spine fracture group, several data points were abstracted: location of the fracture, presence of vertebral artery injury, surgical or nonsurgical treatment of the vertebral artery injury, alteration of treatment (specifically, surgical planning), and any neurologic or cerebrovascular compromise at the time of the most recent follow-up. In the group without a cervical spine fracture, for whom the study was ordered for indications other than cervical trauma, we noted whether the CTangiography of the head and neck was positive for vertebral artery injury. We also evaluated appropriate utilization on the basis of whether our current institutional imaging protocol for CT angiography of the head and neck was used (Table I). This protocol was established on the basis of current
No external funding was received in support of this study.
Results hree hundred and eighty-one patients had a CT of the cervical spine and CT angiography of the head and neck per institutional protocols. One hundred and twenty-six of these patients had cervical spine fracture, and nineteen (15%) of the 126 had vertebral artery injury identified on the CTangiography. All vertebral artery injuries were unilateral, and none of the patients required interventional treatment of the vascular lesion. Anticoagulation was started for sixteen patients, two were not given anticoagulation because of contraindications, and one was not treated because she died from the traumatic injuries. Of the
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TABLE II Number of CT Angiography Studies of the Head and Neck Ordered and Number Positive per Indication in Cervical Fracture Group (N = 126) No. (%) Ordered
No. (%) Positive
Cervical
87 (69%)
17 (20%)
Non-cervical
16 (13%)
1 (6%)
Not indicated per protocol
23 (18%)
1 (4%)
Indication
sixteen patients treated with anticoagulation, twelve took 325 mg of aspirin twice daily or 81 mg daily, one received 40 mg of enoxaparin twice daily, and three were therapeutically treated with warfarin anticoagulation. No complications from anticoagulation were reported. Eleven of the nineteen patients with vertebral artery injury underwent a surgical procedure for the cervical spine fracture, including seven who were treated with a posterior cervical approach; one surgeon elected not to expose the cervical spine on the side without vertebral artery injury to obviate potential injury to the intact vertebral artery. The average duration of follow-up was 152 days (range, seventeen to 777 days). Regardless of whether they underwent surgical or nonsurgical treatment of the cervical fracture, all patients with vertebral artery injury were reported to be neurologically intact without evidence of sequelae from the cerebrovascular injury at the most recent follow-up evaluation. Fractures with associated vertebral artery injury most commonly involved C2 (eleven of the nineteen fractures). Overall, eleven (23%) of forty-eight patients with a C2 fracture had CT angiography that was positive for a vertebral artery injury. Five of the nineteen patients with a vertebral artery injury had a fracture that did not involve C1, C2, or C3, and three of these nineteen patients had noncontiguous cervical injuries. Of the 107 cervical fractures without vertebral artery injury, fiftythree (50%) involved C4-C7. Twenty-one patients in this group had CT angiography of the head and neck ordered off protocol. Of the 126 studies ordered for patients with cervical spine fracture, sixteen were ordered per protocol for a noncervical-spine indication and one of the sixteen was positive for vertebral artery injury. Twenty-three studies in the cervical fracture group were ordered off protocol (for example, for a spinous process fracture not at C1, C2, or C3), and one (4%) of them was positive for vertebral artery injury. The remaining eighty-seven studies were ordered for cervical spine indications per protocol, and seventeen (20%) were positive (Table II). There was no significant difference in the prevalence of positive CT angiography findings between the studies ordered for cervical spine indications and those ordered off protocol (p = 0.113), or between all studies ordered per protocol (for cervical or non-cervical indications) and those ordered off protocol (p = 0.194). There was also no significant difference between studies ordered per protocol for cervical indications and those ordered per protocol for non-cervical indications (p = 0.293), or between studies ordered for cervical indications and those ordered for non-cervical indica-
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tions or off protocol (p = 0.057). Of the 255 patients who did not have a cervical fracture, twenty-four (9.4%) had a CT angiography study of the head and neck that was positive for vertebral artery injury. The billed charge for CT angiography of the head and neck was $3925. The total charge for the twenty-three patients in the fracture group for whom the study was ordered off protocol was $90,275. Although it varies by patient according to body habitus and autocalibration by the scanner, radiation exposure was approximated at 4000 mGy/cm. Thus, in addition to the unwarranted cost for the twenty-three patients for whom the study was ordered off protocol, there was also approximately 92,000 mGy/cm of radiation exposure for all of those patients combined. Contrast-medium load was approximately 100 mL, depending on patient size. There were no reported episodes of anaphylactic reaction to contrast medium or associated nephropathy in the patients in our study. Discussion creening for vertebral artery injury in trauma patients is important because such injuries can be associated with substantial morbidity and mortality if not identified and treated appropriately1,2. Authors of previous studies have attempted to elucidate injury patterns likely to be associated with vertebral artery injury, which has led to the development of protocols for performing CT angiography of the head and neck7-10. The aim of our study was to determine if such tests were utilized appropriately per institutional protocol, if the tests had an effect on treatment of patients with cervical injuries, and the consequences of the findings of these tests. At our institution, the patient charge for a CT angiography of the head and neck was $3925. The studies that were performed off protocol in our series accounted for more than $90,000 in additional expenses over a twenty-month period. Inappropriately ordered tests place an undue burden on the health-care system, and particularly on uninsured or underinsured patients. These studies are not benign. One consequence of CT angiography of the head and neck is exposure to intravenous contrast medium, which can lead to contrast nephropathy in 5% to 38% of patients, depending on other risk factors that may be unknown in obtunded trauma patients such as diabetes or renal failure5. Trauma patients frequently have multiple CT scans and multiple contrast-medium loads as part of the initial evaluation. In addition, they are often hypovolemic on admission, which can increase the risk of contrast nephropathy. Allergic reaction to contrast medium is another concern. Although anaphylaxis has been reported in only 0.1% of patients exposed to contrast medium, any allergic reaction—particularly in a critically ill trauma patient—could have devastating consequences6. In our study population, no patient experienced contrast-medium-related complications. Radiation also poses a substantial risk to patients undergoing CT angiography of the head and neck. The medical literature raises specific concerns about the age at which a patient is exposed to radiation and the amount of radiation
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received. Younger patients have an increased lifetime risk of radiation-induced sarcoma from just one sixty-four-slice coronary angiogram; for example, Huda et al. reported that, for a twenty-year-old woman, such a study leads to a lifetime cancer risk of one in 143, whereas that risk is one in 466 for a sixty-year-old4. Also, long-term follow-up of Japanese patients who survived the atomic bomb blasts has shown that the acute amount of radiation needed to develop a sarcoma in a lifetime is much less than previously documented3. This observation is especially concerning for trauma patients who are often younger and subjected to multiple scans. To our knowledge, no one has calculated the lifetime cancer risk for patients exposed to CT angiography of the head and neck. One way to reduce the risk to patients is by monitoring correct utilization of the tests by developing protocols1,2. The majority of the studies performed in our population were ordered per established institutional protocol either for an indicated cervical fracture pattern (eighty-seven patients; 69%) or other indicated traumatic injuries (sixteen patients; 13%). However, 18% (twenty-three) of the 126 CT angiography studies of the head and neck were ordered and performed for fracture patterns that were not indications per institutional protocol. This exposure to risk did not lead to identification of large numbers of silent vertebral artery injuries as only one (4%) of the studies ordered off protocol was positive. Even the tests ordered per protocol for non-cervical-fracture indications had a low likelihood of being positive. This finding suggests that, in the absence of cervical pathology, the likelihood of vertebral artery injury is low and protocols should be strictly followed to ensure proper utilization of these scans. Seventeen (20%) of the studies ordered for patients with cervical fracture were positive for a vertebral artery injury. This percentage is much higher than that for the studies ordered per protocol for non-cervical injuries and those ordered off protocol, suggesting a benefit in utilizing this modality. However, our data failed to demonstrate that the criteria used for ordering these scans led to a significant difference with regard to the ability to identify vertebral artery injuries. Although our data showed a consistent trend toward an increased prevalence of vertebral artery injury when the study had been ordered for an appropriate cervical fracture, this prevalence was not significantly different from that found with studies ordered for noncervical-fracture indications or those ordered entirely off protocol. Previous authors have reported a high correlation of vertebral artery injuries in the presence of upper cervical (C1C3) fractures, and criteria for imaging protocols have been based on these studies7-9. In the present study, the fracture location most frequently associated with a vertebral artery injury was C2, with almost one in four C2 fractures (eleven patients; 23%) having a positive finding on CT angiography of the head and neck. These eleven C2 fractures accounted for more than half of all positive CT angiography studies of the head and neck in this population. Recent data have raised questions about the traditionally accepted high-risk categories of upper cervical fractures and fractures involving the transverse foramen, and have suggested that vertebral artery injuries are more common
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in association with displaced cervical injuries and among patients presenting with neurologic deficits10. In the present study, all patients were reported to be neurologically intact without evidence of cerebrovascular complications at the time of the most recent follow-up, regardless of the treatment they had received for either the cervical spine fracture or the vertebral artery injury. All vertebral artery injuries were treated pharmacologically, which is consistent with other studies10. Our study had limitations. Certain individuals may have sustained fatal injuries involving the vertebral artery and died before reaching the trauma center. Our search would not have identified such patients. Although the purpose of the study was to evaluate the impact of CT angiography of the head and neck on patients presenting to our trauma center, this possibility also underscores the importance of early imaging of survivors who are at risk. In addition, as this was a retrospective study, it was not possible to standardize treatment of either the vertebral artery injury or the cervical fracture. Our assessment of medical decision-making, particularly with regard to surgical planning, was based on a review of the medical records. It is possible that some surgeons chose nonoperative treatment for the fracture because of the vertebral artery injury but that information was not specified in their notes. Also, because this was a retrospective study, we could not specifically follow laboratory results indicative of renal injury unless they had been ordered. Similarly, we could not track the exact radiation exposure of our patients. Nevertheless, we believe that our estimates of exposure, based on scanner-specific properties, are reasonably accurate. As to whether or not CT angiography of the head and neck matters for patients with cervical spine injury, the answer depends on the reason for the study. Our data indicate that CTangiography of the head and neck is an important screening tool that, if utilized appropriately, can detect vertebral artery injuries, allowing early initiation of pharmacologic treatment. On the other hand, it had little impact on decision-making for operative treatment of cervical fractures, and ‘‘routine’’ CT angiography of the head and neck for ‘‘surgical planning’’ is discouraged. Vertebral artery injuries can be devastating if not diagnosed and treated. Screening examinations, especially in the setting of cervical trauma, are necessary to ensure that a major injury is not missed. We recommend strict adherence to established imaging protocols to ensure that studies are ordered appropriately to minimize the risks and costs associated with unnecessary studies. n
John C. Hagedorn II, MD Sanford E. Emery, MD, MBA John C. France, MD Scott D. Daffner, MD Department of Orthopaedics, West Virginia University, P.O. Box 9196, Morgantown, WV 26506-9196. E-mail address for J.C. Hagedorn II: [email protected]
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References 1. Bromberg WJ, Collier BC, Diebel LN, Dwyer KM, Holevar MR, Jacobs DG, Kurek SJ, Schreiber MA, Shapiro ML, Vogel TR. Blunt cerebrovascular injury practice management guidelines: the Eastern Association for the Surgery of Trauma. J Trauma. 2010 Feb;68(2):471-7. 2. Western Trauma Association. Blunt cerebralvascular injury algorithm. Western Trauma Association 2002-2011. 1 Apr. 2012. http://westerntrauma.org/algorithms/ ScreeningForAndTreatmentOfBluntCerebrovascularInjuries/References.html. Accessed 2013 Dec 17. 3. Samartzis D, Nishi N, Hayashi M, Cologne J, Cullings HM, Kodama K, Miles EF, Funamoto S, Suyama A, Soda M, Kasagi F. Exposure to ionizing radiation and development of bone sarcoma: new insights based on atomic-bomb survivors of Hiroshima and Nagasaki. J Bone Joint Surg Am. 2011 Jun 1;93(11): 1008-15. 4. Huda W, Schoepf UJ, Abro JA, Mah E, Costello P. Radiation-related cancer risks in a clinical patient population undergoing cardiac CT. AJR Am J Roentgenol. 2011 Feb;196(2):W159-65. 5. Trivedi M, Prabhahar T, Preller J. Prevention of contrast induced nephropathy in the critically ill. European Society of Intensive Care Medicine: e-Posters. Vienna 2009.
European Society of Intensive Care Medicine. http://poster-consultation.esicm.org/ ModuleConsultationPoster/posterDetail.aspx?intIdPoster=569. Accessed 2013 Dec 17. 6. Saljoughian M. Intravenous radiocontrast media: a review of allergic reactions. US Pharm. 2012;37(5):HS-14-6. 7. Fassett DR, Dailey AT, Vaccaro AR. Vertebral artery injuries associated with cervical spine injuries: a review of the literature. J Spinal Disord Tech. 2008 Jun;21(4):252-8. 8. Ding T, Maltenfort M, Yang H, Smith HE, Ratliff J, Vaccaro AR, Greg Anderson D, Harrop J. Correlation of C2 fractures and vertebral artery injury. Spine (Phila Pa 1976). 2010 May 20;35(12):E520-4. 9. Oetgen ME, Lawrence BD, Yue JJ. Does the morphology of foramen transversarium fractures predict vertebral artery injuries? Spine (Phila Pa 1976). 2008 Dec 1;33(25): E957-61. 10. Even J, McCullough K, Braly B, Hohl J, Song Y, Lee J, McGirt M, Devin C. Clinical indications for arterial imaging in cervical trauma. Spine (Phila Pa 1976). 2012 Feb 15;37(4):286-91. 11. American Medical Association. CPT 2012 professional edition. Chicago: AMA; 2011.
