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Radiography of facial trauma, the lateral view is not required
Clinical Radiology (1998) 53, 218-220
Radiography of Facial Trauma, the Lateral View is not Required N. RABY and D. MOORE
Department of Radiology, Western Infirmary NHS Trust, Glasgow, UK The value of the lateral radiograph in patients who have sustained facial trauma has been assessed. Three observers each assessed 200 sets of facial radiographs randomly containing either three- (occipito mental, occipito mental 30 and lateral) or two-film series (lateral excluded). No additional fractures were detected with three films. A sensitivity of 90 % and a positive predictive value of 0.90 was seen with both three and two-film series. Specificity was 99.3 % with three films and 97.3 % with two films. These differences are not statistically significant. We conclude that the lateral film can safely be excluded from the initial assessment of patients with facial trauma. Raby, N. & Moore, D. (1998). Clinical Radiology 53, 218-220. Radiography of Facial Trauma, the Lateral View is not Required
Accepted for Publication 4 June 1997
It is common practice for patients attending accident and emergency departments following facial trauma to be referred for facial radiographs. The standard radiology [1-3] and radiographic [4] textbooks advocate that the routine series of films to be obtained comprise of three projections: lateral, occipito mental (OM) and occipito mental with an upward tilt of the face of 30 ~ (OM30). The inclusion of the lateral is based on the fundamental principle that two radiographs at fight angles are essential in providing a three-dimensional evaluation of any bony injury. There is, however, anecdotal evidence that many radiology departments have decided not to include the lateral view on a standard facial series on the basis that it provides little useful information in the initial evaluation of the majority of patients. This paper seeks to determine whether this is clinically acceptable practice. We have found no other paper which has specifically addressed this question.
observer therefore viewed a total of 200 sets of films. The observers were asked to decide whether there was evidence of a facial fracture on each of the films presented and to indicate their level of confidence on a 10 cm analogue scale. All films were accompanied by an evaluation form on which observers recorded their findings for each film. With a threefilm series the form contained supplementary questions to be answered only if a fracture was demonstrated on any of the films. This included an area to allow observers to comment on whether any additional information had been obtained from the lateral film. Results were analysed using the Wilcoxon matched pairs test. The radiation dose contributed by each projection was calculated by measuring the entrance surface dose using thermoluminescent dosemeters (TLD). Ten TLDs were exposed for each facial projection using a skull phantom.
RESULTS METHODS A letter was sent to 36 Scottish X-ray departments requesting information on their current policy concerning routine radiographic projections obtained in the initial evaluation of patients with facial trauma. The computer records of our radiology department were searched for all patients referred for facial radiographs for the period 30 October 1994 to 1 September 1995 and the subsequent radiological diagnoses were recorded. The radiographs of 50 patients who were diagnosed and managed as having sustained a facial fracture or fracture complex were randomly mixed with 50 sets of radiographs which had previously been assessed as normal and viewed independently by three observers (one consultant in musculoskeletal radiology and two radiology registrars with at least 2 years radiology experience). Film series were viewed in batches with random mixtures of two film series (excluding lateral) and three film series (including lateral). In later batches the same film series were represented with the lateral film removed or added as appropriate. All patient identification and the date of examination was masked. Each Correspondence to: Dr N. Raby, Department of Radiology, Western Infirmary NHS Trust, Glasgow G11 6NT, UK. 9 1998 The Royal College of Radiologists.
Replies were received from all 36 departments questioned. Seventy-seven per cent of departments do not include a lateral film in their routine series. In 20% a three-film series including a lateral is used. Three per cent had no specific policy. The departmental computer search revealed that from a total of 1106 facial radiographs 993 (89.8%) were reported as showing no abnormality. Fractures were present in 71 (6.4%). An abnormality, e.g. sinus fluid level was reported in 42 (3.8%) with no associated fracture demonstrated. There was no difference in the performance of any of the observers in detecting fractures when presented with two films or three (Tables 1 & 2). No more fractures were identified with a three-film series than with two films. Table 1 - Cumulative results for all three observers with three films
Observer interpretation True status
Fracture
Normal
Fracture Normal
135 1
15 149
219
FACIAL TRAUMA RADIOGRAPHY
Table 2 - Cumulative results for all three observers and two films
Table 4 - Mean entrance skin dose (EDS) and percentage each projection represents of the total
Observer interpretation True status
Fracture
Normal
Fracture Normal
135 4
15 146
This was true for each individual observer and is reflected in the cumulative results tables. A sensitivity of 90% and a positive predictive value of 0.90 was seen with both three and two-film series. Specificity was 99.3% with three films and 97.3% with two films. These differences are not statistically significant. There was quite marked interobserver variance in the number of cases where a fracture was detected on the lateral film, and whether this observation added further information regarding the degree of fracture displacement (Table 3). There was no difference in the confidence levels of reporting of fractures. The mean confidence level for a fracture was 9.4 for both two and three-film series. Identifying the fracture on the lateral did not increase confidence of diagnosis. The radiation dose measurements (Table 4) show that the lateral film represents 11.5% of the total of the radiation dose of a three-film facial series.
DISCUSSION It has been standard practice to obtain three radiographs in the evaluation of patients with facial trauma. The lateral film is included in the sound principle that views at fight angles to each other are required to fully evaluate any bony injury. The initial purpose of radiographing such patients is to determine whether any bone injury has occurred at all. There are many instances where two radiographs in orthogonal planes are essential to make this determination, for example, the ankle or wrist. Such literature as exists on the utility of the lateral facial film centres on the additional information it yields when a fracture is present [5,6]. There is however no literature available on the information provided by the lateral film in the initial identification of fractures. From the evidence of this study the lateral film does not provide any assistance in determining whether a fracture is present or not. The addition of the lateral film to the two commonly used frontal radiographs did not result in the detection of any additional fractures nor did it alter the confidence of interpretation of any observer. It is recognized that in this study observers viewed batches of films where 50% of cases demonstrated a Table 3 - Number of cases (from total of 50) in which a fracture was identified on the lateral film and the number of occasions this was thought to provide additional diagnostic information
Projection
ESD (mGy)
Total dose (%)
OM OM33 Lateral
3.6 2.5 0.8
52.1 36,2 11.5
fracture. This is different from day to day practice where only 6.4% of our patients would have a fracture. This may alter the true positive and negative predictive values but from our data these alterations would be very small and would not invalidate our findings. We believe that these results therefore lend support to those departments who already utilize a two frontal film policy. Such a policy results in an 11.5% reduction in radiation dose with no detrimental effects on diagnosis and thus concurs with the ALARA (as low as reasonably achievable) principle. In our department, performing approximately 1100 examinations per year, savings of about s could be made. Within our department the great majority (>90%) of patients referred for radiography do not have a bony injury. In this large group of patients it is clear that a lateral film is never required. Since all of these patients can be confidently identified on a two-film series, the lateral film can be safely omitted. In those patients in whom a fracture is identified local policy can be defined. Although there is no doubt that further diagnostic information may be obtained from the lateral film, CT scanning is probably the further investigation of choice usually at the request of a maxillofacial surgeon. It must be stressed that the majority of patients in the study group had suffered only a minor to moderate degree of trauma, usually a punch to the face during a fist fight. The injury was usually unilateral and not associated with any other major trauma although associated head and chest trauma may have occurred. This is probably the commonest type of facial trauma seen in accident and emergency. The type of facial injuries sustained in these circumstances are likely to reflect the fractures seen in a typical accident and emergency department and indeed the study group were taken from consecutive patients attending our accident and emergency department. This is in contradistinction to those who have suffered obvious major facial trauma such as may be seen in road traffic victims flung through a car window or who have received a beating with sustained multiple blows to head and face with a wooden or metal implement. Such patients are likely to have sustained a Le Fort type injury and full radiological assessment including a lateral film and/ or computed tomography (CT) are likely to be required. These patients have clinically apparent major facial trauma and rarely represent an initial diagnostic problem.
CONCLUSIONS Observer
A B C
Fracture seen on lateral
Additional information
26 7 14
20 1 3
9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 218-220.
In the initial evaluation of facial trauma the lateral film may safely be excluded with no loss of identification of fractures. If a fracture is identified on the OM and OM30 films further information may be obtained from a lateral film and/or CT scanning dependant on local preferences and machine availability.
220
CLINICAL RADIOLOGY
Acknowledgements. We wish to express our thanks to Dr M. Fleet and Dr I. McGlinchey for their assistance with this study and to Dr Gordon Murray of the Robertson Centre of Biostatistics, University of Glasgow for statistical advice.
REFERENCES 1 Young JWR. Skeletal trauma regional. In: Sutton D, ed. A textbook of radiology and imaging, 5th ed. Edinburgh: Churchill Livingstone 1993.
2 Mclvor J. Maxillo facial radiology. In: Grainger RG & Allison DJ, eds. Diagnostic radiology, 2nd ed. Edinburgh: Churchill Livingstone, 1992: 2165-2201. 3 Rogers L, ed. Radiology of skeletal trauma, 2nd ed. Edinburgh: Churchill Livingston, 1992. 4 Bull S. Skeletal radiography. Oxford: Butterworths, 1986. 5 Pathria MN, Blaser SI. Diagnostic imaging of craniofacial fractures. Radiologic Clinics of North America 1989;27:839-853. 6 Daffner RH, Apple JS, Gehweiler JA. Lateral view of facial fractures: new observations. American Journal of Roentgenology 1983; 14l:587591.
9 1998 The Royal College of Radiologists, ClinicalRadiology, 53, 218-220.
Radiography of Facial Trauma, the Lateral View is not Required N. RABY and D. MOORE
Department of Radiology, Western Infirmary NHS Trust, Glasgow, UK The value of the lateral radiograph in patients who have sustained facial trauma has been assessed. Three observers each assessed 200 sets of facial radiographs randomly containing either three- (occipito mental, occipito mental 30 and lateral) or two-film series (lateral excluded). No additional fractures were detected with three films. A sensitivity of 90 % and a positive predictive value of 0.90 was seen with both three and two-film series. Specificity was 99.3 % with three films and 97.3 % with two films. These differences are not statistically significant. We conclude that the lateral film can safely be excluded from the initial assessment of patients with facial trauma. Raby, N. & Moore, D. (1998). Clinical Radiology 53, 218-220. Radiography of Facial Trauma, the Lateral View is not Required
Accepted for Publication 4 June 1997
It is common practice for patients attending accident and emergency departments following facial trauma to be referred for facial radiographs. The standard radiology [1-3] and radiographic [4] textbooks advocate that the routine series of films to be obtained comprise of three projections: lateral, occipito mental (OM) and occipito mental with an upward tilt of the face of 30 ~ (OM30). The inclusion of the lateral is based on the fundamental principle that two radiographs at fight angles are essential in providing a three-dimensional evaluation of any bony injury. There is, however, anecdotal evidence that many radiology departments have decided not to include the lateral view on a standard facial series on the basis that it provides little useful information in the initial evaluation of the majority of patients. This paper seeks to determine whether this is clinically acceptable practice. We have found no other paper which has specifically addressed this question.
observer therefore viewed a total of 200 sets of films. The observers were asked to decide whether there was evidence of a facial fracture on each of the films presented and to indicate their level of confidence on a 10 cm analogue scale. All films were accompanied by an evaluation form on which observers recorded their findings for each film. With a threefilm series the form contained supplementary questions to be answered only if a fracture was demonstrated on any of the films. This included an area to allow observers to comment on whether any additional information had been obtained from the lateral film. Results were analysed using the Wilcoxon matched pairs test. The radiation dose contributed by each projection was calculated by measuring the entrance surface dose using thermoluminescent dosemeters (TLD). Ten TLDs were exposed for each facial projection using a skull phantom.
RESULTS METHODS A letter was sent to 36 Scottish X-ray departments requesting information on their current policy concerning routine radiographic projections obtained in the initial evaluation of patients with facial trauma. The computer records of our radiology department were searched for all patients referred for facial radiographs for the period 30 October 1994 to 1 September 1995 and the subsequent radiological diagnoses were recorded. The radiographs of 50 patients who were diagnosed and managed as having sustained a facial fracture or fracture complex were randomly mixed with 50 sets of radiographs which had previously been assessed as normal and viewed independently by three observers (one consultant in musculoskeletal radiology and two radiology registrars with at least 2 years radiology experience). Film series were viewed in batches with random mixtures of two film series (excluding lateral) and three film series (including lateral). In later batches the same film series were represented with the lateral film removed or added as appropriate. All patient identification and the date of examination was masked. Each Correspondence to: Dr N. Raby, Department of Radiology, Western Infirmary NHS Trust, Glasgow G11 6NT, UK. 9 1998 The Royal College of Radiologists.
Replies were received from all 36 departments questioned. Seventy-seven per cent of departments do not include a lateral film in their routine series. In 20% a three-film series including a lateral is used. Three per cent had no specific policy. The departmental computer search revealed that from a total of 1106 facial radiographs 993 (89.8%) were reported as showing no abnormality. Fractures were present in 71 (6.4%). An abnormality, e.g. sinus fluid level was reported in 42 (3.8%) with no associated fracture demonstrated. There was no difference in the performance of any of the observers in detecting fractures when presented with two films or three (Tables 1 & 2). No more fractures were identified with a three-film series than with two films. Table 1 - Cumulative results for all three observers with three films
Observer interpretation True status
Fracture
Normal
Fracture Normal
135 1
15 149
219
FACIAL TRAUMA RADIOGRAPHY
Table 2 - Cumulative results for all three observers and two films
Table 4 - Mean entrance skin dose (EDS) and percentage each projection represents of the total
Observer interpretation True status
Fracture
Normal
Fracture Normal
135 4
15 146
This was true for each individual observer and is reflected in the cumulative results tables. A sensitivity of 90% and a positive predictive value of 0.90 was seen with both three and two-film series. Specificity was 99.3% with three films and 97.3% with two films. These differences are not statistically significant. There was quite marked interobserver variance in the number of cases where a fracture was detected on the lateral film, and whether this observation added further information regarding the degree of fracture displacement (Table 3). There was no difference in the confidence levels of reporting of fractures. The mean confidence level for a fracture was 9.4 for both two and three-film series. Identifying the fracture on the lateral did not increase confidence of diagnosis. The radiation dose measurements (Table 4) show that the lateral film represents 11.5% of the total of the radiation dose of a three-film facial series.
DISCUSSION It has been standard practice to obtain three radiographs in the evaluation of patients with facial trauma. The lateral film is included in the sound principle that views at fight angles to each other are required to fully evaluate any bony injury. The initial purpose of radiographing such patients is to determine whether any bone injury has occurred at all. There are many instances where two radiographs in orthogonal planes are essential to make this determination, for example, the ankle or wrist. Such literature as exists on the utility of the lateral facial film centres on the additional information it yields when a fracture is present [5,6]. There is however no literature available on the information provided by the lateral film in the initial identification of fractures. From the evidence of this study the lateral film does not provide any assistance in determining whether a fracture is present or not. The addition of the lateral film to the two commonly used frontal radiographs did not result in the detection of any additional fractures nor did it alter the confidence of interpretation of any observer. It is recognized that in this study observers viewed batches of films where 50% of cases demonstrated a Table 3 - Number of cases (from total of 50) in which a fracture was identified on the lateral film and the number of occasions this was thought to provide additional diagnostic information
Projection
ESD (mGy)
Total dose (%)
OM OM33 Lateral
3.6 2.5 0.8
52.1 36,2 11.5
fracture. This is different from day to day practice where only 6.4% of our patients would have a fracture. This may alter the true positive and negative predictive values but from our data these alterations would be very small and would not invalidate our findings. We believe that these results therefore lend support to those departments who already utilize a two frontal film policy. Such a policy results in an 11.5% reduction in radiation dose with no detrimental effects on diagnosis and thus concurs with the ALARA (as low as reasonably achievable) principle. In our department, performing approximately 1100 examinations per year, savings of about s could be made. Within our department the great majority (>90%) of patients referred for radiography do not have a bony injury. In this large group of patients it is clear that a lateral film is never required. Since all of these patients can be confidently identified on a two-film series, the lateral film can be safely omitted. In those patients in whom a fracture is identified local policy can be defined. Although there is no doubt that further diagnostic information may be obtained from the lateral film, CT scanning is probably the further investigation of choice usually at the request of a maxillofacial surgeon. It must be stressed that the majority of patients in the study group had suffered only a minor to moderate degree of trauma, usually a punch to the face during a fist fight. The injury was usually unilateral and not associated with any other major trauma although associated head and chest trauma may have occurred. This is probably the commonest type of facial trauma seen in accident and emergency. The type of facial injuries sustained in these circumstances are likely to reflect the fractures seen in a typical accident and emergency department and indeed the study group were taken from consecutive patients attending our accident and emergency department. This is in contradistinction to those who have suffered obvious major facial trauma such as may be seen in road traffic victims flung through a car window or who have received a beating with sustained multiple blows to head and face with a wooden or metal implement. Such patients are likely to have sustained a Le Fort type injury and full radiological assessment including a lateral film and/ or computed tomography (CT) are likely to be required. These patients have clinically apparent major facial trauma and rarely represent an initial diagnostic problem.
CONCLUSIONS Observer
A B C
Fracture seen on lateral
Additional information
26 7 14
20 1 3
9 1998 The Royal College of Radiologists, Clinical Radiology, 53, 218-220.
In the initial evaluation of facial trauma the lateral film may safely be excluded with no loss of identification of fractures. If a fracture is identified on the OM and OM30 films further information may be obtained from a lateral film and/or CT scanning dependant on local preferences and machine availability.
220
CLINICAL RADIOLOGY
Acknowledgements. We wish to express our thanks to Dr M. Fleet and Dr I. McGlinchey for their assistance with this study and to Dr Gordon Murray of the Robertson Centre of Biostatistics, University of Glasgow for statistical advice.
REFERENCES 1 Young JWR. Skeletal trauma regional. In: Sutton D, ed. A textbook of radiology and imaging, 5th ed. Edinburgh: Churchill Livingstone 1993.
2 Mclvor J. Maxillo facial radiology. In: Grainger RG & Allison DJ, eds. Diagnostic radiology, 2nd ed. Edinburgh: Churchill Livingstone, 1992: 2165-2201. 3 Rogers L, ed. Radiology of skeletal trauma, 2nd ed. Edinburgh: Churchill Livingston, 1992. 4 Bull S. Skeletal radiography. Oxford: Butterworths, 1986. 5 Pathria MN, Blaser SI. Diagnostic imaging of craniofacial fractures. Radiologic Clinics of North America 1989;27:839-853. 6 Daffner RH, Apple JS, Gehweiler JA. Lateral view of facial fractures: new observations. American Journal of Roentgenology 1983; 14l:587591.
9 1998 The Royal College of Radiologists, ClinicalRadiology, 53, 218-220.