Evaluation of the Canadian CT Head Rule for Minor Head Trauma in a Tertiary Referral Institution Essam A. Elgamal1, Sherif M. El-Watidy1, Zain A. Jamjoom1, Ali Abdel-Raouf 1, Hamdy Hassan2, Hassan Alwaraqi3, Sabry Al-Malah3
Abstract Background: The value of cranial computerized tomography (CT) scan as a method of predicting traumatic brain injury (TBI) in patients with minor head trauma (MHT) is controversial. We aimed to assess the effectiveness of cranial CT by retrospectively studying head-injured patients presenting to the accident and emergency (A&E) department in a tertiary referral institution; King Khalid University Hospital, Riyadh, Saudi Arabia. Objectives: To determine the frequency of utilization, yield for TBI, incidence of missed injuries, and to assess the effectiveness of cranial CT for patients with MHT. Methods: These retrospective medical records and imaging survey were conducted for 600 consecutive patients. Included in this review were patients above 12 years who sustained acute MHT, defined as witnessed loss of consciousness or amnesia and a Glasgow Coma Scale (GCS) score of 13 or greater. Results: During the year 2004, and over a 10-month period, 600 patients attended the A&E department with MHT. Only 130 patients (21.7%) fulfilled the indication criteria of the Canadian CT Head Rule, and were referred for cranial CT scan. Findings: CT scans demonstrated evidence of intracranial injuries in 24 patients (18.5%), 19 of them admitted for observation, and only two patients (1.5%) required craniotomy for evacuation of extradural hematoma. Brain CT was normal in 100 patients (77%), showing incidental findings unrelated to head injury in five
patients, and one scan could not be interpreted due to poor quality. No one died as a consequence of MHT, and no one reported again to A&E of the discharged group, without CT scan. Conclusion: There have been several studies examining the indications for CT scan imaging in MHT. Canadian CT Head Rule can accurately identify patients who have no need for head CT imaging, however, if applied to the wrong patients or used incorrectly, it may lead to unnecessary referrals for CT. If successfully validated, this simple decision rule may lead to a more standardized approach to the A&E investigation and management of patients with MHT, this would potentially reduce costs, and so should be considered for application by all A&E, neurosurgery, and radiology departments. Key Words CT scan · Minor head trauma · Canadian CT head rules · Intracranial hemorrhage Eur J Trauma 2006;32:527–32 DOI 10.1007/s00068-006-5156-8
Introduction Most patients (80–90%) who sustain a minor head trauma (MHT) do not need admission to the hospital and almost all are sent home with appropriate instructions. Considering the large number of people affected, the routine use of computerized tomography (CT) scan
Neurosurgery Division, King Khalid University Hospital, Riyadh, Saudi Arabia, 2 Radiology Department, King Khalid University Hospital, Riyadh, Saudi Arabia, 3 Emergency Department, King Khalid University Hospital, Riyadh, Saudi Arabia. Received: November 30, 2005; revision accepted: September 30, 2006
Elgamal EA, et al. The Canadian CT Head Rule for Minor Head Trauma
is rather expensive, not always practical, and involves legal problems for inappropriate radiological imaging. Although the vast majority of patients with MHT go on to make an uneventful recovery, a few patients with unrecognized intracranial injury (hemorrhage, contusion, edema, or laceration to the brain substance or meninges) deteriorate and become neurologically devastated, severely disable or die [1, 2]. A “head injury” is best defined as an injury that is clinically evident on physical examination and is recognized by the presence of ecchymoses, lacerations, deformities, or cerebrospinal fluid (CSF) leakage. A traumatic brain injury (TBI) refers specifically to an injury to the brain itself and is not always clinically evident; if unrecognized, it may result in an adverse outcome . Traditionally, MHT has been defined as blunt head trauma in a patient with a Glasgow Coma Scale (GCS) score of 13 to 15 . The primary management objective in MHT is to identify those patients who are at risk of developing complications, specifically an intracranial hemorrhage requiring admission to the hospital and proper management. Clinical assessment alone is always inadequate for the detection of ICH , and radiological procedures are therefore used as additional screening tools. Since only 3–13% of patients with GCS score of 15 will have a positive CT, and less than 1% of these patients will have a lesion requiring a neurosurgical intervention, a lot of controversies exist about the detection of factors that make a patient of MHT a high-risk candidate for developing intracranial complications [3, 6, 7, 8]. Although the most reliable approach remains the history and physical examination, selective use of technology is also useful to reach maximum accuracy. Patients with moderate or severe head injury usually show obvious clinical signs, simplifying the decision to perform a head CT scan. However, this decision becomes less evident when evaluating those patients with MHT. Many studies have examined the ability of physicians to predict intracranial injury and addressed guidelines for the management of MHT, the most widely used is the Canadian CT Head Rule [3, 9, 10, 11]. Canadian CT Head Rule The CT head is indicated for patients with MHT and have any one of the following. High Risk Patients (for Neurosurgical Intervention) (1) GCS < 15 at 2 h after the injury.
(2) Suspected open or depressed skull fracture. (3) Any sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhoea/rhinorrhoea, Battle’s sign). (4) Vomiting two or more episodes. (5) Age 65 years or older. Medium Risk (for Brain Injury on CT) (1) Amnesia before impact for more than 30 min. (2) Dangerous mechanism (pedestrian struck by a motor vehicle, occupant ejected from motor vehicle, fall from height; 3 feet or more than five stairs). Methods A retrospective study of medical records and CT scan images of 600 consecutive patients aged 12 years or more was carried out. These patients presented, over a 10-month period during the year 2004, to the A&E department at King Khalid University Hospital; a tertiary referral teaching centre in Riyadh, Saudi Arabia. All patients included in the study sustained witnessed acute MHT, and had a transient loss of consciousness or amnesia with a GCS score of 13 or greater. Data were obtained for each patient from the A&E records on which information was recorded at presentation, with respect to their age, sex, mode of arrival at hospital, initial complaint, GCS Score at different stages, vomiting, memory of events, and destination after leaving A&E (whether discharged home with head injury observation instructions or admitted to the hospital). Cranial CT scans performed for 130 patients who fulfilled the indication criteria of the Canadian CT Head Rule. Scans were reviewed by a neurosurgeon and a neuroradiologist, and correlated with the history and clinical findings, looking at the indications for CT scanning, CT findings, and the outcome of management of each patient. Results All medical records of 600 patients enrolled in the study were assessed. Among them 470 (78.3%) patients were discharged home after a certain period of observation and they did not develop complications related to MHT. Most of them did not return back to the hospital for the same reason. The remaining 130 patients (21.7%) were referred for CT scan on the day of injury (median time to CT = 0 days), have been studied in details.
Demographic Features and Mechanism of Injury Of the 130 patients, who were referred for CT head, 120 (92.3%) were males and 10 (7.7%) were females; their ages ranged from 12 to 85 years, with a mean ± SD of 20.6 ± 6.1 years (Table 1). Patients falling into the age group 12–30 years (n = 101 patients) constituted majority of the patients. Traffic accident (n = 109) was the most common cause of injury (Table 2). Sixty percent of them were brought by ambulance service while the rest walked into the A&E. CT Scan: Indication and Findings Indication for cranial CT scan was clearly recorded in the medical notes of 125 patients utilizing the Canadian CT Head Rule, summarized in (Table 3). CT scan was essentially normal in 67 patients (58.7%) and showed positive findings in 62 patients, one scan was of too poor quality to interpret. Twenty-four patients (18.5%) were judged to have a clinically important brain injury. Another 38 patients (29.2%) were judged to have clinically unimportant CT findings, which for the most part consisted of scalp laceration or hematoma, old infarction, or brain atrophy (Table 4). Management and Outcome The 470 patients (78.3%) who, according to the Canadian CT Head Rule, did not have an indication for CT scan discharged from A&E with head injury observation instructions, and did not develop complications related to MHT, and no cranial images have been requested from the day of discharge till reviewing their medical records, a period between 6 and 16 months. Of the 62 patients with abnormal CT scans, 19 were admitted for observation. Two (0.3%) patients required neurosurgical intervention for evacuation of extradural hematoma (Figure 1). Eight patients had asymptomatic extracerebral hematoma, extradural (n = 5) (Figure 2a) and subdural (n = 3) (Figure 3), were treated conservatively, and follow-up scans showed resolution of the blood (Figure 2b). Two patients with cerebral contusion in their scans had recovered without complications (Figure 4). Of all patients, no mortality recorded as a consequence of MHT. Discussion Although head injury is a common condition presenting to A&E departments, the true incidence of MHT is unknown. Epidemiologic studies have focused on those patients managed in trauma centers, and many patients
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Elgamal EA, et al. The Canadian CT Head Rule for Minor Head Trauma
with its potential to produce severe neurologic disability or even death, has led some authors to advocate CT imaging in virtually all patients with MHT. This strategy generated large numbers of negative CT scans and many of the injuries detected did not require medical or surgical intervention . On the other hand, performing routine cranial CT scans on every patient with MHT is ineffective and unjustified due to the cost involved, and is not readily available in many rural hospitals. The limited availability of CT and the low yield of positive CT scans makes it sometimes unjustifiable to transfer all patients with minor head injury from district to tertiary referral centers . Vilke et al.  studied the value of a detailed neurologic examination, including a careful mental status assessment, in predicting the presence of an acute intracranial lesion on CT scan. The authors concluded that a decision for CT cannot be based solely on the Figure 1. CT scan after MHT showing large extradural hematoma required craniotomy evacuation. neurologic examination. The Canadian CT Head Rule has developed selective imaging recommendations who sustain MHT do not seek medical care and are thus for patients with MHT, and uniformly found that all not included in the estimates, thereby underestimating patients with significant intracranial lesions exhibit histhe true incidence of MHT . This, however, does torical or physical evidence, suggesting the presence of not mean that MHT is a totally benign condition. An intracranial injury. It represents a potentially valuable outcome study of patients who had a head injury suggetool in the clinical assessment of MHT. Its sensitivity for sted that patients with a low risk of dying, that is patibrain injuries requiring neurosurgical intervention and ents with MHT, are at the greatest risk of inadequate for those requiring hospitalization and follow-up were diagnosis and treatment . 100 and 98.6%, respectively . CT scan of the brain is the cornerstone test in the A significant percentage of patients admitted with evaluation of TBI in head trauma. It has an acceptable GCS of 13 to 15, and fulfilled the Canadian CT Head sensitivity and specificity as a test for the presence or Rule, had abnormalities on CT scan. As expected an absence of ICH. Fear of missing an intracranial injury, inverse relationship between GCS and CT scan abnormalities was found. For GCS of 13, 14, and 15, the respective percentage of CT abnormalities were 55, 40, and 16%. Stein & Ross  in a similar retrospective study found that for GCS of 13, 14, and 15, the respective percentages of CT abnormalities were 38, 24, and 13%. In addition, more than 10% of our patients with an initial GCS of 13 required surgery, whereas approximately 3% required surgery when GCS was 15. In Figure 2a and 2b. CT scan showing right temporal extradural hematoma in asymptomatic patient after MHT treated conservatively. b) CT scan after 5 days showing the hematoma starting to resolve. a study of 3,370 patients
with initial GCS of 13 to 15, Culotta et al.  found that surgery was required for 4.5% of patients with initial GCS of 13 and 0.4% of those with GCS of 15. Because of the well-documented correlation between lower GCS score and increased incidence of intracranial injury, some argue that patients with a GCS score of 13 or 14 should not be included in the same group as those with a GCS score of 15 and that all patients with an abnormal GCS score should undergo CT scanning [4, 18]. The first step of the patient assessment is to assign them to an injury category: mild, moderate, or severe. There have been cases that initially presented as mild injuries, but later have shown significant neurobehavioral and cognitive deficits . Such misrepresentation of expected outcomes invites examination of the evaluation processes used to determine injury categorization. Though making such a distinction would seem simple, there can be serious consequences associated with underestimating the degree of damage in TBI. This has led to the introduction of other protocols to guide the use of CT for patients with MHT such as the New Orleans Criteria for patients with GCS of 15. However, Canadian CT head rules found to have higher specificity for important clinical outcomes than does the New Orleans Criteria, and has greater potential for reducing the use of CT scans [20, 21]. On the other hand, the use of plain skull radiography is being now disputed . Skull film radiographs are not recommended in the evaluation of MHT. Although the presence of a skull fracture increases the likelihood of an intracranial lesion, its sensitivity is not sufficient to be a useful screening test. Indeed, negative findings on skull films may mislead the clinician . There is no doubt that patients with MHT, who present 6 h after sustaining the injury, have a normal clinical examination, and who have a head CT scan that does not demonstrate acute injury can be safely discharged from the A&E department. Patients can be discharged after a shorter period of observation if they are under the care of a responsible third party . However, deciding “to scan or not to scan,” or “to admit or not to admit” remains more art than science, with most physicians probably erring “to stay on the safe side.” Victims of MHT are mostly young males constituting 74% of patients’ population in our study and 90% were due to road accidents. This is also reflected by the fact that road accidents is considered one of the most common causes of death in youngsters in Saudi
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Elgamal EA, et al. The Canadian CT Head Rule for Minor Head Trauma
Arabia. Most patients with MHT included in this study, and were not referred for CT scan, live within the catchment area of the hospital primary health care centers where the same medical records are used. We could not find in their notes any entry indicating an untoward complication related to their head trauma, during the period of follow-up which ranged from 6 to 16 months. Conclusion The Canadian CT Head Rule can accurately identify patients who have no need for head CT imaging. It is methodologically sound, clinically useful, and highly a sensitive prediction rule for detecting clinically important brain injuries. However, if applied to the wrong patients or used incorrectly, it may lead to unnecessary referrals for CT. If successfully validated, this simple decision rule may lead to a more standardized approach to the A&E investigation and management of patients with MHT and would potentially reduce costs. Although most people presenting to the A&E departments with an MHT were discharged straight home, patients with a GCS score of 13 or 14 should be considered as high-risk MHT, and they would probably require emergency cranial CT scan examination. The Canadian CT Head Rule has been developed using a limited number of clinical criteria that are accessible to the treating physician in the A&E department to identify patients with MHT who have essentially no risk of brain injury. However, if the clinician has a heightened level of suspicion, it may appropriate to perform a head CT scan even if the patient is fully oriented, and has a GCS score of 15. The confusion in having standard indication criteria for CT in MHT remains to be determined by a multicenter, collaborative prospective study.
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Address for Correspondence Essam A. Elgamal, FRCS (SN) Assistant Professor and Consultant Neurosurgery Division King Khalid University Hospital PO Box 7805, Riyadh 11472 Saudi Arabia Phone (+966/1)467-1273, Fax -9493 e-mail: [email protected]