Accepted Manuscript Mandibular Fractures: An Analysis of the Epidemiology and Patterns of injury in 4143 Fractures Christopher Morris, DMD, MD, Nicolas P. Bebeau, DMD, MD, Hans Brockhoff, DDS, MD, Resident, Rahul Tandon, DMD, Resident, Paul Tiwana, DDS, MD, MPH PII:
S0278-2391(15)00022-1
DOI:
10.1016/j.joms.2015.01.001
Reference:
YJOMS 56615
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 3 March 2014 Revised Date:
5 January 2015
Accepted Date: 6 January 2015
Please cite this article as: Morris C, Bebeau NP, Brockhoff H, Tandon R, Tiwana P, Mandibular Fractures: An Analysis of the Epidemiology and Patterns of injury in 4143 Fractures, Journal of Oral and Maxillofacial Surgery (2015), doi: 10.1016/j.joms.2015.01.001. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Mandibular Fractures: An Analysis of the Epidemiology and Patterns of injury in 4143 Fractures
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Paul Tiwana DDS, MD, MPH (corresponding author) Program Director, University of Texas Southwestern Medical Center/Parkland Address: UT Southwestern Medical Center Division of Oral and Maxillofacial Surgery 5323 Harry Hines Blvd, Dallas TX 75390-9159 Telephone: 214-645-3979 E-mail: [email protected]
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Christopher Morris DMD, MD (first Author) Private Practice, Colleyville, TX, Clincal Faculty, John Peter Smith Hospital Department of Oral and Maxillofacial Surgery Nicolas P Bebeau DMD, MD Private Practice Scottsdale, AZ
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Hans Brockhoff, DDS, MD Resident, University of Texas Southwestern Medical Center/Parkland
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Rahul Tandon, DMD Resident, University of Texas Southwestern Medical Center/Parkland
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Mandibular Fractures: Epidemiology and Patterns of injury in 4143 Fractures
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Christopher D. Morris, DDS, MD Nicolas P. Bebeau, DDS, MD
Hans C. Brockhoff II, DDS, MD Rahul Tandon, DMD
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Paul Tiwana DDS, MD, MS, FACS
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Abstract Purpose:
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The objective of this study is to complete a comprehensive retrospective review of the epidemiology and patterns of injury in mandibular trauma based on the Parkland Memorial Hospital Trauma database over a 17 year time period. 4,143 fractures were identified in 2,828 patients from our databank. In mandibular trauma, the mechanism of injury, along with several other variables, can be an important point of differentiation with regards to fracture pattern. By demonstrating the statistical relationship between these and fracture pattern, we hope to provide surgeons with a better understanding of such a relationship. Patients and Methods:
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Mandibular Fracture Data was collected from the Parkland Memorial Hospital trauma registry using ICD-9 (International Classification of Diseases) codes (802.21-802.39). Information included fracture type, age, gender, mechanism of injury, and associated injuries. The Parkland Trauma Registry yielded 4,143 mandibular fractures in 2,828 patients managed at Parkland Memorial Hospital between 1993-2010. 4,143 fractures were identified in 2,828 patients. Results:
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Conclusion:
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Based on the retrospective analysis, results were obtained for the following: age, gender, monthly distribution, anatomical distribution, and mechanism of injury. The average age was approximately 38 years, with the majority of patients (33%) in the 3rd decade. An overwhelming majority of patients were male (83.27%), with only 16.27% comprising females. The majority of injuries occurred in the summer months, with July being the highest. The mechanism of injury predominantly involved low-velocity blunt injuries (62%) when compared with high-velocity blunt injuries (31%). The anatomical distribution of fractures evaluated is as follows: angle (27%), symphysis (21.3%), condyle/subcondyle (18.4%), and body (16.8%).
This study helps provide and support the relationship between several variables associated many of the common traumatic injuries seen in the mandible. This analysis can be used to help surgeons identify and anticipate injuries based on age, gender, and mechanism of injury.
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Introduction
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Maxillofacial trauma remains one of the most common, yet challenging aspects of oral and maxillofacial surgery. The variety of anatomical involvement, mechanisms, and forms of injury all present challenges to even the most experienced trauma surgeon. Of all the bones in the maxillofacial region, the mandible still remains one of the most commonly injured bones in the trauma setting. The complexity of the mandibular injuries is not just limited to its different anatomical and functional components, but can be related to numerous other variables that have not yet been fully explored.
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Categorizing, and then correlating, the various mandibular injuries can prove to be challenging. Firstly, it is important to have an appropriate number of patients with a wide distribution of injuries to the relevant areas of the mandible. Secondly, the data must be elucidated over an extended period of time, namely 10-15 years at a minimum. These two factors – data gathering factors – might be the most challenging aspect of a study of this magnitude. Previous studies have focused on variables such as gender, age, etiology of injury, treatment options, associated injuries in the maxillofacial region, and complications. Although the importance of such information cannot be understated, it is our belief that further analysis can lead to an even greater insight into less salient patterns. Additionally, limiting our study to mandibular injuries and associated fracture patterns within specific mandibular anatomical sites can demonstrate significant correlations.
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Ellis et al analyzed over 3,400 mandibular fractures during a 10- year period from 19741983. [1] To our knowledge, this is one of the largest retrospective studies performed in assessing mandibular fractures alone. Nevertheless, the study predates many of the large public safety advances over the last 30 years such as mandatory seatbelt wear, vehicular airbags, and more routine use of mouth guards or helmets with facemasks in athletic activity to name but just a few. In addition, the study analyzed patients in a different country (Scotland). Although etiologies of injuries remain relatively uniform across the world (assaults, MVAs, etc.), the distribution of such etiologies may differ from country to country.
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More recent retrospective studies have also been performed, albeit with a smaller patient size and shorter time period. One such study in the US showed that over a 5 year period, the angle and body were not just the most commonly fractured sites, but also found to be fractured together the majority of the time. [2] Although this study analyzed nearly 380 patients, over 80% of the patients were injured due to assault. Another study in India, however, demonstrated that over 72% of fractures were due to traffic accidents. [3] Similar studies in countries such as Australia, the Netherlands, Brazil, and Turkey, along with studies in the USA, show variations in etiologies, both in specific types and percentages. [4] [5] [6] [7] Therefore, assessing the etiological factors can vary depending on location.
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A recent study conducted by Martinez et al., compared two sets of trauma patients 20 years apart. [8] In this study, there were significant changes in several variables involved in maxillofacial trauma, including etiology and age. Their results concluded with a decrease in assault injuries in the younger population and an increase in fall-related injuries in the elderly. [8]
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It is clear, based on these previous studies, that an understanding of mechanism-based factors resulting in various patterns of injury is valuable to the surgeon in the management of mandibular fractures. By studying many of the variables previously assessed, as well as subcategorizing many others (including mechanism of injury), we believe that we can provide the necessary data and statistical analysis to confidently describe certain patterns seen in the trauma setting. Identifying such patterns can provide surgeons with the ability to better predict, and subsequently manage many of these injuries. Many surgeons are faced with such dilemmas, and in an acute setting, timing can prove be a critical factor in patient outcome.
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This study provides the largest statistical sample compiled to date for the purpose of investigating patterns of mandibular injury in a major U.S. urban trauma center. Based on our extensive retrospective analysis from 1993-2010, we have identified several factors, both surgical and non-surgical, that can provide correlations between the different types of injuries commonly seen in the mandibular trauma setting. The purpose of this study is to allow identification of population and mechanism-based risk factors for patients presenting with mandibular fractures.
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Materials and Methods
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The UT Southwestern Medical Center Institutional Review Board approved the study protocol and all sensitive patient information was removed prior to analysis. Mandibular Fracture Data was collected from the Parkland Memorial Hospital trauma registry using ICD-9 (International Classification of Diseases) codes (802.21-802.39). Information included fracture type, age, gender, month of injury, mechanism of injury, and associated mandibular injuries. Data was aggregated and analyzed using a Microsoft Excel Spreadsheet. Results
The Parkland Trauma Registry yielded 4,143 mandibular fractures in 2,828 patients managed at Parkland Memorial Hospital between 1993-2010. 4,143 fractures were identified in 2,828 patients. These fractures were all managed by a single surgical service allowing a degree of consistency in coding and treatment. Several subsets of data were subsequently identified in patients with mandibular fractures to age and gender, annual and monthly distribution, anatomic distribution, number of sites, and mechanism of injury.
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Age and Gender Distribution
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The mean age was 38 years with ages ranging from 1 to 97 years of age. The most prevalent age groups were the 2nd, 3rd, and 4th decades with the 3rd decade making up 1/3 of the total. [Table 1][Figure 1] There was a male predominance of 83%. Of the 2,828 patients 2,355/2,828 patients (83.27%) were male and 473/2,828 (16.73%) were female. [TABLE 1][FIGURE 1]
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Monthly Distribution
[TABLE 2] Anatomic Distribution of Injury
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Annual Incidence ranged from 106 to 187 patients per year. Monthly distribution data was available for 2,545 patients rather than 2,828. Over the 17-year period, fractures were relatively more common in the summer months with July being the most common month of occurrence. [Table 2]
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The injury distribution by site regardless of mechanism was Angle 27.0%, Symphysis 21.3%, Condyle/Subcondyle 18.4%, Body 16.8%, Multiple Sites Unspecified 7.1%, Ramus 5.4%, Alveolar Border 2.9%, Coronoid 1.0%. [Table 3] [TABLE 3]
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Number of Sites Multiple fractures within the mandible represented just over 50% of the total (1426 of the 2,828) with 1402 fractures limited to a single site. [Figure 2][Table 4] [FIGURE 2] [TABLE 4]
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Site association was investigated, namely if one encounters a fracture at one site what is the incidence of fracture in a second site. These figures are reported in the following tables. [Figures 3-8], [Tables 5-10] [FIGURE 3] [TABLE 5]
[FIGURE 4] [TABLE 6]
[FIGURE 5] [TABLE 7]
[FIGURE 6] [TABLE 8]
[FIGURE 7] [TABLE 9]
[FIGURE 8] [TABLE 10]
Mechanism Mechanism of injury was generally subdivided into high and low velocity blunt, and high and low velocity penetrating injuries, as well as not specified. A comparison of these
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mechanisms is shown [Table 11]. Further subdivisions of the known mechanisms (excluding “not specified”) include high velocity penetrating (firearm (i.e. gunshot wounds) – 6.9%), low velocity penetrating (knife wounds – 0.6%), high velocity blunt (Motor Vehicle Collision – MVC (24.25%), Motor Cycle Collision – MCC (3.33%), Motor Pedestrian Collision – MPC (3.28%) – 31%), Low velocity blunt (Interpersonal Conflict – IPC (47.43%), Falls (9.7%), Sports related injuries (4.51) – 62%) and other (not otherwise classified - 27.8%). [Table 12] Anatomic distribution of injury was further characterized based on mechanism of injury. [Table 13] [Figures 9-13]
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[TABLE 11] [TABLE 12] [TABLE 13] Discussion
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Age and Gender Distribution
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Review of the literature indicates the most common causes of mandible fractures are the result of interpersonal conflict or motor vehicle collisions. [1] [9] [10] [11] In this discussion, mandibular fractures are categorized by mechanism of injury and further sub-classified into low-velocity blunt, low-velocity penetrating, high-velocity blunt and high-velocity penetrating injuries. This is to emphasize the effect of mechanism on the clinical presentation of these types of injuries.
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As expected, the number of children reported in this study is low as Parkland Hospital is located immediately adjacent to Children’s Medical Center of Dallas, a Level-1 children’s trauma center that is the receiving center of pediatric trauma. Therefore, one can expect the number of mandible fractures in those ages 0 to 18 to be higher than reported in this study.
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Of note, our data recorded 2,840 patients sustaining mandible fractures. This is due to the fact that 12 patients from years 1992 to 2010 had their decade birthdays (20 to 21, 30 to 31, 40 to 41) while in the hospital being treated for their fractures. Therefore, these patients were included in two separate decades and the actual total number of patients was 2,828. Monthly Distribution
The annual incidence of mandible fractures ranged from 106 to 187 patients per year at Parkland Memorial Hospital. Of the 2,828 patients reported in this study, 2,545 are available for data as the others lack admission date or month documentation. Presumably, this data was lost when Parkland Hospital moved from paper to electronic medical records in 2007.
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In the 17-years represented by this study, July was the month with the greatest percentage of mandibular fractures (10.6%) followed by August (9.7%), September (8.8%) and June (8.8%). In general mandibular fractures present more frequently in the summer months. These months correlate to the summer months in North America and Europe (above the equator), such a distribution would be likely to change in countries in South American and Australia, where the summer months are from November to February. Incidence by Mechanism of Injury
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According to the Parkland Trauma Registry, 2,828 patients between 1992 and 2010 suffered mandibular fractures. All fractures were classified using ICD-9 coding data. Of the 2,828 patients, 787 (28.7%) were not included in this review because the mechanism was unspecified. Therefore, the total number of patients presenting with a mandibular fracture secondary to a known mechanism was 2,041.
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In our study, the majority of mandibular fractures were the result of low-velocity blunt injuries (61.6%). This is twice the incidence of fractures resulting from high-velocity blunt (30.9%) mechanisms. As expected, penetrating injuries resulted in a relatively low number of fractures with a larger number the result of high-velocity penetrating (6.9%) compared with low-velocity penetrating (0.6%) mechanisms. [FIGURE 9]
[FIGURE 12]
[FIGURE 11]
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[FIGURE 10]
[FIGURE 13]
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After review of the data, 4,143 mandible fractures were identified. 1,057 of these fractures were not included in this review as their ICD-9 codes were coded as multiplesites unspecified. Therefore, 3,086 mandibular fractures were evaluated in this data subset.
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Like Fridrich et al [2], the most common site of fracture in this review was the mandibular angle (28.5%). The second most common site of fracture was the mandibular symphysis (21.4%). Other sites of fracture included the condyle/subcondyle (17.6%), body (17.5%), ramus (4.0%), alveolus (2.5%) and coronoid (1.1%). Multiple unspecified comprised the remaining fractures (7.4%). When mandibular fractures are categorized by mechanism, it becomes clear that a correlation exists between the mechanism, direction of force and type of fracture. As indicated earlier, low-velocity blunt mechanisms comprised the largest number of fractures in this study (2,328 fractures). Of the fractures resulting from low-velocity blunt mechanisms (interpersonal violence, sports-related injury, falls or struck by falling object), the mandibular angle was the most common site of fracture (31.49%). This is expected when one considers that the
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majority of low-velocity blunt injuries are the result of interpersonal violence. A blow to the side of the face as occurs when one is struck with largely will result in a strike against the mandibular angle. This was followed by fractures of the symphysis (21.26%), body (17.70%), and condyle/subcondyle (16.07%).
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High-velocity blunt mechanisms (motor vehicle collisions, motorcycle collisions, motor pedestrian collisions) resulted in a greater number of condylar fractures (25.4%) followed by symphysis fractures (22.8%) when compared to other sites. This may be expected when considering the vector of force often applied to the mandible during these collisions is largely in an anterior-posterior direction. The initiation of force is at the chin with transference posteriorly to the condyles.
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High-velocity penetrating mechanisms (firearms) reflected what we consider to be a non-anatomic pattern of injury. More specifically, the patterns of injury are more significantly affected by the properties of the projectile than the biomechanical properties of the mandible. This is expected considering that bullets travel in a random fashion as they ricochet off bones and are redirected through the tissues. These injuries resulted commonly in mandibular body fractures (24.0%) followed by symphysis (16.5%), angle (15.7%), condyle/subcondyle (8.3%), ramus (9.1%), coronoid (3.3%) and alveolus (0.8%) fractures.
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Low-velocity penetrating mechanisms (knife) bared a more predictable pattern as those areas of the mandible more readily exposed to stab injuries were most commonly affected. The most common sites of fracture in these injuries were the mandibular symphysis (21.4%), body (14.3%), angle (14.3%) and ramus (14.3%). This was followed by condyle/subcondyle (7.1%) and alveolus (7.1%). No fractures of the coronoid were reported.
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In each category (low-velocity blunt, high-velocity blunt, low-velocity penetrating, highvelocity penetrating), a number of fractures were excluded due to their classification in ICD-9 as “multiple-sites unspecified.” As expected, the largest number of unspecified fractures occurred in the low-velocity blunt category (156 fractures) as this was the largest sample (2,328 fractures). This indicates that 6.7% of this data is unusable in this type of study due to an inability to classify location. The largest percentage of fractures unclassified was found in high-velocity penetrating (27 fractures or 22.3%) trauma. This is expected given the high-level of destruction and comminution frequently characteristic of these types of injuries. There is often a higher number of lifethreatening co-morbidities requiring immediate management and resulting in less attention to coding of non-life threatening injuries. High-velocity blunt mechanism required exclusion of 6.9% of the total number of fractures (43 fractures) while lowvelocity penetrating required exclusion of 21.4% (3 fractures). Fracture Patterns According to this review just under half of the fractures were at a single site (49.6%). Mandibular fractures with a fracture at more than one site accounted for just over half
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of the fractures (50.4%) with a large number being two sites (34.3%), followed by three (4.8%) four (0.85%) and five sites (0.1%).
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There were a total of 4,143 fractures in 2,828 patients in this study, averaging 1.47 fractures per mandible. The highest number of fractures occurred at the mandibular angle (1123), followed by the mandibular symphysis (882), condyle/subcondyle complex (761), body (695) and ramus (225). It is the opinion of the authors that a specific association between different locations of fractures is an important consideration when performing clinical assessment of a patient with a mandible fracture. Knowledge that one particular type of fracture may be more likely with a fracture at another location can aide in diagnosis. To our knowledge, this is the first study to address the association between particular sites of mandibular injury.
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According to this study, condyle fractures were most frequently associated with concomitant symphysis fractures (51.9%), followed by mandibular body (27.4%), angle (11.8%), ramus (4.8%), alveolar (2.6%) and coronoid fractures (1.4%). Clearly, a correlation exists between mandibular condyle and symphysis fractures. When one considers that the direction of force applied to the mandible to result in a fracture of the mandibular symphysis is transmitted to the condylar region, this association is anatomically predictable. As a note, there was no way using ICD-9 coding to associate bilateral condyle fractures as coding does not differentiate between the right and left condyle.
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As previously mentioned, it is expected that force applied to the anterior mandible would result in a transmission of the force posteriorly. The mandibular ramus is no different. Like the mandibular condyle, the ramus is most often associated with symphysis fractures (36.7%), followed by mandibular body (30.2%), condyle/subcondyle complex (18.3%), angle (5.5%), coronoid (5.5%) and alveolus (3.7%). Again, when considering direction of force this may be expected.
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According to our results, the mandibular angle was most often associated with concomitant symphysis fractures (47.3%). This was followed by mandibular angle and body fractures (41.0%), condyle (9.3%), ramus (1.1%), alveolar (0.7%) and coronoid fractures (0.3%). The mandibular body is most often associated with concomitant angle fractures (52.5%) followed by condyle fractures (27.7%). Other associated fractures included the mandibular symphysis (10.2%), ramus (8.0%), coronoid (0.7%) and alveolus (0.7%). The mandibular symphysis is most often associated with concomitant angle fractures (44.0%) or condylar complex fractures (38.2%). Other associated fractures include the mandibular body (7.4%), ramus (7.1%), alveolus (2.6%) and coronoid (0.5%). When examining alveolar process fractures, according to our data, the practitioner should be wary of the possibility of concomitant injury to the mandibular body (40.5%) and condyle (29.7%). This is followed by the mandibular ramus (10.8%), angle (10.8%)
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and symphysis (8.1%). No association existed between alveolar process and coronoid fractures according to our data.
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In comparison with the previously published largest study (1) there are some similarities and differences with our contemporary review. In both cases, the peak month of mandibular fractures was July at approximately 10%. Assaults were the main cause of the majority of fractures in both studies (48.15% in 1985, vs. 62% in 2014); however, our study showed a higher incidence of motor vehicle accidents than the 1985 study (24.25 to 15%). Regarding low velocity blunt injuries, which included assaults, our study showed that while angle fractures comprised a similar percentage (31.49% in 1985 to 30.6% in 2014), there were significant differences in condylar, body, and symphyseal fractures (24.3, 32.8, and 7.1% in 1985 vs. 16.07, 17.7, and 21.26% in 2014). Comparing the high velocity blunt injuries (MVC), it is clear that differences exist regarding fractures of the condyle, angle, body, and symphysis (34.1, 10.9, 34.8, and 11.7% in 1985 vs. 25.4, 20.1, 15.1, and 22.8% in 2014). Considering the samples size for both studies is comparable (3462 in 1985 vs. 4143 in 2014), these differences demonstrate changes in fracture patterns over the last 25 years.
Conclusion
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A weakness of the study is the inability to identify completely isolated mandibular fractures due to the limits of the ICD-9 coding system. For instance, a condyle fracture can be coded with ICD-9 data as a condylar fracture but we are not able to report with certainty that the condyle was not associated with another fracture at the same anatomic location (i.e. bilateral condyles) as we are not in possession of the modifier codes used to bill for fractures at the same anatomic location but differentiated on laterality (right vs. left). The same can be said with the ramus, angle, body and symphysis. We are unable to report on the incidence of bilateral condyle, ramus, angle, body or symphysis fractures. It is the author’s opinion that although this is a limitation in our study design, the large number of patients allows for some generalizations and can be used as a gauge when calculating general percentages of isolated fractures.
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Epidemiologic studies of various conditions are useful when properly utilized. General conclusions in regards to patterns of injury, associated co-morbidities, and treatment require classification and stratification based on certain variables. In the case of mandibular fractures the mechanism of injury appears to be an important point of stratification in regards to injury pattern, and more importantly has a bearing on the type and number of associated injuries. The surgeon should take into account the mechanism of injury and vector of force when evaluating patients with mandibular fractures. Further study will stratify mechanism of injury for patients presenting with mandibular fractures and correlation with other more serious injuries including cervical spine and vascular injuries.
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Acknowledgments: The authors would like to gratefully acknowledge the contributions to this article and dedicate this review to the memory of Robert V. Walker DDS (19242011).
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References
1. Ellis E, 3rd, Moos KF, el-Attar A: Ten years of mandibular fractures: an analysis of 2,137 cases. Oral Surg Oral Med Oral Pathol 1985;59:120
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2. Gutta R, Tracy K, Johnson C, James LE, Krishnan DG, Marciani RD: Outcomes of mandible fracture treatment at an academic tertiary hopital: a 5-year analysis. J Oral Maxillofac Surg 2014;72:550-558.
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3. Naveen SA, Naveen SV, Hegde N, et al.: The pattern of the maxillofacial fractures – a multicenter retrospective study. J Craniomaxillofac Surg 2012;40(8):675
4. Cbalag MS, Wasiak J, Andre NE, Tang J, et al.: Epidemiology and management of maxillofacial fractures in an Australian trauma centre. J Plast Reconstr Aesthet Surg 2014;67(2):183
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5. Van Hout WM, Van Cann EM, Abbink JH, Koole R: An epidemiological study of maxillofacial fractures requiring surgical treatment at a tertiary trauma centre between 2005 and 2010. Br J Oral Maxillofac Surg 2013;51(5):416
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6. Martins MM, Homsi N, Pereria CC, Jardim EC, Garcia IR: Epidemiologic evaluation of mandibular fractures in the Rio de Janeiro high-complexity hospital. J Craniofac Surg. 2011;22(6):2026
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7. Simsek S, Simsek B, Abubaker AO, Laskin DM: A comparative study of mandibular fractures in the United States and Turkey. Int J Oral Maxillofac Surg 2007;36(5):395. 8. Martinez AY, Como JJ, Vacca M, Nowak MJ, Thomas CL, Claridge JA: Trends in maxillofacial trauma: a comparison of two cohorts of patients at a single institution 20 years apart. J Oral Maxillofac Surg 2014;72:750 9. Fridrich KL, Pena-Velasco G, Olson RA: Changing trends with mandibular fractures: a review of 1,067 cases. J Oral Maxillofac Surg 1992;50:586 10. King RE, Scianna JM, Petruzzelli GJ: Mandible fracture patterns: a suburban trauma center experience. Am J Otolaryngol 2004;25:301
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11. Olson RA, Fonseca RJ, Zeitler DL, Osbon DB: Fractures of the mandible: a review of 580 cases. J Oral Maxillofac Surg 1982;40:23
FIGURE 4: Ramus fractures (N:109) TABLE 6: Ramus fractures (N:109) FIGURE 5: Angle fractures (N:526) TABLE 7: Angle fractures (N:526) FIGURE 6: Symphysis fractures (N:565) TABLE 8: Symphysis fractures (N:565)
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FIGURE 7: Body fractures (N: 411) TABLE 9: Body fractures (N: 411)
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FIGURE 3: Condyle/Subcondyle fractures (N: 832) TABLE 5: Condyle/Subcondyle fractures (N: 832)
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FIGURE 1. Incidence of fracture by age TABLE 1. Age by decade TABLE 2. Fractures by month TABLE 3. Fracture distribution by location FIGURE 2. Number of mandibular fractures by site TABLE 4. Number of mandibular fractures by site
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FIGURE LEGEND
FIGURE 8: Alveolar fractures (N: 37) TABLE 10: Alveolar fractures (N: 37)
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TABLE 11: Mechanism of Injury: N=2828 TABLE 12: Mechanism of Injury subdivided - Mechanism not specified excluded (N:2,041) TABLE 13: Anatomic distribution of mandible Fractures by Mechanism
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FIGURE 9: Mandible fractures by mechanism of injury FIGURE 10: Low velocity blunt (N: 2,328) FIGURE 11: High velocity blunt (N: 623) FIGURE 12: High velocity penetrating (N: 121) FIGURE 13: Low velocity penetrating (N: 14)
TABLES
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Table 1: Age by Decade Decade 0-10: 11-20: 21-30: 31-40: 41-50: 51-60: 61-70: 71-80: 81-90: Total:
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0.78 20.83 33.31 23.37 14.43 4.81 1.41 0.78 0.28 100.00
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Table 2: Fractures by Month Month January February March April May June July August September October November December
% 22 589 942 661 408 136 40 22 8
Patients 173 161 212 209 217 223 270 248 223 220 192 197 2545
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Table 3: Fracture Distribution by Location Location Angle Symphysis Condyle/Subcondyle Body Multiple Sites Unspecified Ramus Alverolar Border Coronoid Total
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% 1120 882 761 696 295 225 122 42 4143
27.0 21.3 18.4 16.8 7.1 5.4 2.9 1.0 100.00
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Table 4: Number of Mandibular Fractures by Site Site(s) N 1 Site 1402 Multiple Sites 1426 2 Sites 969 3 Sites 135 4 Sites 24 5 Sites 3 Multiple Sites Unspecified 295
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Table 5: Condyle/Subcondyle Fractures (N: 832) and Incidence of Fractures in a 2nd Site Coronoid Process 1.4% 12/832 Ramus 4.8% 40/832 Angle 11.8% 98/832 Body 27.4% 228/832 Alveolus 2.6% 22/832 Symphysis 51.9% 432/832
% 49.58% 50.42% 34.26% 4.77% 0.85% 0.11% 10.43%
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Table 6: Ramus Fractures (N: 109) and Incidence of Fractures in a 2nd site Condyle/Subcondyle 18.3% 20/109 Coronoid Process 5.5% 6/109 Angle 5.5% 6/109 Body 30.2% 33/109 Alveolus 3.7% 4/109 Symphysis 36.7% 40/109
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Table 7: Angle Fractures (N: 526) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 9.3% 49/526 Coronoid Process 0.3% 2/526 Ramus 1.1% 6/526 Body 41.0% 216/526 Alveolus 0.7% 4/526 Symphysis 47.3% 249/526
Table 8: Symphysis Fractures (N: 565) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 38.2% 216/565 Coronoid Process 0.5% 3/565 Ramus 7.1% 40/565 Angle 44.0% 249/565 Body 7.4% 42/565 Alveolus 2.6% 15/565
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Table 9: Body Fractures (N: 411) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 27.7% 114/411 Coronoid Process 0.7% 3/411 Ramus 8.0% 33/411 Angle 52.5% 216/411 Alveolus 0.7% 3/411 Symphysis 10.2% 42/411
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Table 10: Alveolar Fractures (N: 37) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 29.7% 11/37 Coronoid Process 0% 0/37 Ramus 10.8% 4/37 Angle 10.8% 4/37 Body 40.5% 15/37 Symphysis 8.1% 3/37
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Table 11: Mechanism of Injury, N=2828 High Velocity High Velocity Low Velocity Low Velocity Not Specified Blunt Penetrating Blunt Penetrating Injuries 563 141 1325 12 786 19.9% 5.0% 46.9% 0.4% 27.8%
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Table 12: Mechanism of Injury Subdivided (Mechanism Not Specified Excluded), N=2041 Interpersonal Sports Fall Motor Motor Motor Firearm Knife Conflict Vehicle Pedestrian Cycle Collision Collision/Bicycle Collision 968 92 198 495 67 68 141 12 47.43% 4.51% 9.70% 24.25% 3.28% 3.33% 6.91% 0.59%
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% 16.07% 1.07% 4.04% 31.49% 17.70%
Symphysis Alveolar Border Multiple Unspecified
21.26% 1.68% 6.7%
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20 1 27
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Table 13: Anatomic Distribution of Mandibular Fractures by Mechanism High Velocity Low Velocity High Velocity Low Velocity Penetrating Penetrating Blunt Blunt Location N=121 % N=14 % N=623 % N=2328 Condyle/Subcondyle 10 8.3% 1 7.1% 158 25.4% 374 Coronoid 4 3.3% 0 0% 6 1.0% 25 Ramus 11 9.1% 2 14.3% 16 2.6% 94 Angle 19 15.7% 2 14.3% 125 20.1% 733 Body 29 24.0% 2 14.3% 96 15.4% 412 495 39 156
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S0278-2391(15)00022-1
DOI:
10.1016/j.joms.2015.01.001
Reference:
YJOMS 56615
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 3 March 2014 Revised Date:
5 January 2015
Accepted Date: 6 January 2015
Please cite this article as: Morris C, Bebeau NP, Brockhoff H, Tandon R, Tiwana P, Mandibular Fractures: An Analysis of the Epidemiology and Patterns of injury in 4143 Fractures, Journal of Oral and Maxillofacial Surgery (2015), doi: 10.1016/j.joms.2015.01.001. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Mandibular Fractures: An Analysis of the Epidemiology and Patterns of injury in 4143 Fractures
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Paul Tiwana DDS, MD, MPH (corresponding author) Program Director, University of Texas Southwestern Medical Center/Parkland Address: UT Southwestern Medical Center Division of Oral and Maxillofacial Surgery 5323 Harry Hines Blvd, Dallas TX 75390-9159 Telephone: 214-645-3979 E-mail: [email protected]
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Christopher Morris DMD, MD (first Author) Private Practice, Colleyville, TX, Clincal Faculty, John Peter Smith Hospital Department of Oral and Maxillofacial Surgery Nicolas P Bebeau DMD, MD Private Practice Scottsdale, AZ
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Hans Brockhoff, DDS, MD Resident, University of Texas Southwestern Medical Center/Parkland
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Rahul Tandon, DMD Resident, University of Texas Southwestern Medical Center/Parkland
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Mandibular Fractures: Epidemiology and Patterns of injury in 4143 Fractures
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Christopher D. Morris, DDS, MD Nicolas P. Bebeau, DDS, MD
Hans C. Brockhoff II, DDS, MD Rahul Tandon, DMD
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Paul Tiwana DDS, MD, MS, FACS
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Abstract Purpose:
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The objective of this study is to complete a comprehensive retrospective review of the epidemiology and patterns of injury in mandibular trauma based on the Parkland Memorial Hospital Trauma database over a 17 year time period. 4,143 fractures were identified in 2,828 patients from our databank. In mandibular trauma, the mechanism of injury, along with several other variables, can be an important point of differentiation with regards to fracture pattern. By demonstrating the statistical relationship between these and fracture pattern, we hope to provide surgeons with a better understanding of such a relationship. Patients and Methods:
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Mandibular Fracture Data was collected from the Parkland Memorial Hospital trauma registry using ICD-9 (International Classification of Diseases) codes (802.21-802.39). Information included fracture type, age, gender, mechanism of injury, and associated injuries. The Parkland Trauma Registry yielded 4,143 mandibular fractures in 2,828 patients managed at Parkland Memorial Hospital between 1993-2010. 4,143 fractures were identified in 2,828 patients. Results:
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Conclusion:
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Based on the retrospective analysis, results were obtained for the following: age, gender, monthly distribution, anatomical distribution, and mechanism of injury. The average age was approximately 38 years, with the majority of patients (33%) in the 3rd decade. An overwhelming majority of patients were male (83.27%), with only 16.27% comprising females. The majority of injuries occurred in the summer months, with July being the highest. The mechanism of injury predominantly involved low-velocity blunt injuries (62%) when compared with high-velocity blunt injuries (31%). The anatomical distribution of fractures evaluated is as follows: angle (27%), symphysis (21.3%), condyle/subcondyle (18.4%), and body (16.8%).
This study helps provide and support the relationship between several variables associated many of the common traumatic injuries seen in the mandible. This analysis can be used to help surgeons identify and anticipate injuries based on age, gender, and mechanism of injury.
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Introduction
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Maxillofacial trauma remains one of the most common, yet challenging aspects of oral and maxillofacial surgery. The variety of anatomical involvement, mechanisms, and forms of injury all present challenges to even the most experienced trauma surgeon. Of all the bones in the maxillofacial region, the mandible still remains one of the most commonly injured bones in the trauma setting. The complexity of the mandibular injuries is not just limited to its different anatomical and functional components, but can be related to numerous other variables that have not yet been fully explored.
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Categorizing, and then correlating, the various mandibular injuries can prove to be challenging. Firstly, it is important to have an appropriate number of patients with a wide distribution of injuries to the relevant areas of the mandible. Secondly, the data must be elucidated over an extended period of time, namely 10-15 years at a minimum. These two factors – data gathering factors – might be the most challenging aspect of a study of this magnitude. Previous studies have focused on variables such as gender, age, etiology of injury, treatment options, associated injuries in the maxillofacial region, and complications. Although the importance of such information cannot be understated, it is our belief that further analysis can lead to an even greater insight into less salient patterns. Additionally, limiting our study to mandibular injuries and associated fracture patterns within specific mandibular anatomical sites can demonstrate significant correlations.
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Ellis et al analyzed over 3,400 mandibular fractures during a 10- year period from 19741983. [1] To our knowledge, this is one of the largest retrospective studies performed in assessing mandibular fractures alone. Nevertheless, the study predates many of the large public safety advances over the last 30 years such as mandatory seatbelt wear, vehicular airbags, and more routine use of mouth guards or helmets with facemasks in athletic activity to name but just a few. In addition, the study analyzed patients in a different country (Scotland). Although etiologies of injuries remain relatively uniform across the world (assaults, MVAs, etc.), the distribution of such etiologies may differ from country to country.
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More recent retrospective studies have also been performed, albeit with a smaller patient size and shorter time period. One such study in the US showed that over a 5 year period, the angle and body were not just the most commonly fractured sites, but also found to be fractured together the majority of the time. [2] Although this study analyzed nearly 380 patients, over 80% of the patients were injured due to assault. Another study in India, however, demonstrated that over 72% of fractures were due to traffic accidents. [3] Similar studies in countries such as Australia, the Netherlands, Brazil, and Turkey, along with studies in the USA, show variations in etiologies, both in specific types and percentages. [4] [5] [6] [7] Therefore, assessing the etiological factors can vary depending on location.
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A recent study conducted by Martinez et al., compared two sets of trauma patients 20 years apart. [8] In this study, there were significant changes in several variables involved in maxillofacial trauma, including etiology and age. Their results concluded with a decrease in assault injuries in the younger population and an increase in fall-related injuries in the elderly. [8]
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It is clear, based on these previous studies, that an understanding of mechanism-based factors resulting in various patterns of injury is valuable to the surgeon in the management of mandibular fractures. By studying many of the variables previously assessed, as well as subcategorizing many others (including mechanism of injury), we believe that we can provide the necessary data and statistical analysis to confidently describe certain patterns seen in the trauma setting. Identifying such patterns can provide surgeons with the ability to better predict, and subsequently manage many of these injuries. Many surgeons are faced with such dilemmas, and in an acute setting, timing can prove be a critical factor in patient outcome.
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This study provides the largest statistical sample compiled to date for the purpose of investigating patterns of mandibular injury in a major U.S. urban trauma center. Based on our extensive retrospective analysis from 1993-2010, we have identified several factors, both surgical and non-surgical, that can provide correlations between the different types of injuries commonly seen in the mandibular trauma setting. The purpose of this study is to allow identification of population and mechanism-based risk factors for patients presenting with mandibular fractures.
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Materials and Methods
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The UT Southwestern Medical Center Institutional Review Board approved the study protocol and all sensitive patient information was removed prior to analysis. Mandibular Fracture Data was collected from the Parkland Memorial Hospital trauma registry using ICD-9 (International Classification of Diseases) codes (802.21-802.39). Information included fracture type, age, gender, month of injury, mechanism of injury, and associated mandibular injuries. Data was aggregated and analyzed using a Microsoft Excel Spreadsheet. Results
The Parkland Trauma Registry yielded 4,143 mandibular fractures in 2,828 patients managed at Parkland Memorial Hospital between 1993-2010. 4,143 fractures were identified in 2,828 patients. These fractures were all managed by a single surgical service allowing a degree of consistency in coding and treatment. Several subsets of data were subsequently identified in patients with mandibular fractures to age and gender, annual and monthly distribution, anatomic distribution, number of sites, and mechanism of injury.
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Age and Gender Distribution
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The mean age was 38 years with ages ranging from 1 to 97 years of age. The most prevalent age groups were the 2nd, 3rd, and 4th decades with the 3rd decade making up 1/3 of the total. [Table 1][Figure 1] There was a male predominance of 83%. Of the 2,828 patients 2,355/2,828 patients (83.27%) were male and 473/2,828 (16.73%) were female. [TABLE 1][FIGURE 1]
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Monthly Distribution
[TABLE 2] Anatomic Distribution of Injury
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Annual Incidence ranged from 106 to 187 patients per year. Monthly distribution data was available for 2,545 patients rather than 2,828. Over the 17-year period, fractures were relatively more common in the summer months with July being the most common month of occurrence. [Table 2]
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The injury distribution by site regardless of mechanism was Angle 27.0%, Symphysis 21.3%, Condyle/Subcondyle 18.4%, Body 16.8%, Multiple Sites Unspecified 7.1%, Ramus 5.4%, Alveolar Border 2.9%, Coronoid 1.0%. [Table 3] [TABLE 3]
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Number of Sites Multiple fractures within the mandible represented just over 50% of the total (1426 of the 2,828) with 1402 fractures limited to a single site. [Figure 2][Table 4] [FIGURE 2] [TABLE 4]
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Site association was investigated, namely if one encounters a fracture at one site what is the incidence of fracture in a second site. These figures are reported in the following tables. [Figures 3-8], [Tables 5-10] [FIGURE 3] [TABLE 5]
[FIGURE 4] [TABLE 6]
[FIGURE 5] [TABLE 7]
[FIGURE 6] [TABLE 8]
[FIGURE 7] [TABLE 9]
[FIGURE 8] [TABLE 10]
Mechanism Mechanism of injury was generally subdivided into high and low velocity blunt, and high and low velocity penetrating injuries, as well as not specified. A comparison of these
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mechanisms is shown [Table 11]. Further subdivisions of the known mechanisms (excluding “not specified”) include high velocity penetrating (firearm (i.e. gunshot wounds) – 6.9%), low velocity penetrating (knife wounds – 0.6%), high velocity blunt (Motor Vehicle Collision – MVC (24.25%), Motor Cycle Collision – MCC (3.33%), Motor Pedestrian Collision – MPC (3.28%) – 31%), Low velocity blunt (Interpersonal Conflict – IPC (47.43%), Falls (9.7%), Sports related injuries (4.51) – 62%) and other (not otherwise classified - 27.8%). [Table 12] Anatomic distribution of injury was further characterized based on mechanism of injury. [Table 13] [Figures 9-13]
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[TABLE 11] [TABLE 12] [TABLE 13] Discussion
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Age and Gender Distribution
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Review of the literature indicates the most common causes of mandible fractures are the result of interpersonal conflict or motor vehicle collisions. [1] [9] [10] [11] In this discussion, mandibular fractures are categorized by mechanism of injury and further sub-classified into low-velocity blunt, low-velocity penetrating, high-velocity blunt and high-velocity penetrating injuries. This is to emphasize the effect of mechanism on the clinical presentation of these types of injuries.
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As expected, the number of children reported in this study is low as Parkland Hospital is located immediately adjacent to Children’s Medical Center of Dallas, a Level-1 children’s trauma center that is the receiving center of pediatric trauma. Therefore, one can expect the number of mandible fractures in those ages 0 to 18 to be higher than reported in this study.
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Of note, our data recorded 2,840 patients sustaining mandible fractures. This is due to the fact that 12 patients from years 1992 to 2010 had their decade birthdays (20 to 21, 30 to 31, 40 to 41) while in the hospital being treated for their fractures. Therefore, these patients were included in two separate decades and the actual total number of patients was 2,828. Monthly Distribution
The annual incidence of mandible fractures ranged from 106 to 187 patients per year at Parkland Memorial Hospital. Of the 2,828 patients reported in this study, 2,545 are available for data as the others lack admission date or month documentation. Presumably, this data was lost when Parkland Hospital moved from paper to electronic medical records in 2007.
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In the 17-years represented by this study, July was the month with the greatest percentage of mandibular fractures (10.6%) followed by August (9.7%), September (8.8%) and June (8.8%). In general mandibular fractures present more frequently in the summer months. These months correlate to the summer months in North America and Europe (above the equator), such a distribution would be likely to change in countries in South American and Australia, where the summer months are from November to February. Incidence by Mechanism of Injury
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According to the Parkland Trauma Registry, 2,828 patients between 1992 and 2010 suffered mandibular fractures. All fractures were classified using ICD-9 coding data. Of the 2,828 patients, 787 (28.7%) were not included in this review because the mechanism was unspecified. Therefore, the total number of patients presenting with a mandibular fracture secondary to a known mechanism was 2,041.
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In our study, the majority of mandibular fractures were the result of low-velocity blunt injuries (61.6%). This is twice the incidence of fractures resulting from high-velocity blunt (30.9%) mechanisms. As expected, penetrating injuries resulted in a relatively low number of fractures with a larger number the result of high-velocity penetrating (6.9%) compared with low-velocity penetrating (0.6%) mechanisms. [FIGURE 9]
[FIGURE 12]
[FIGURE 11]
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[FIGURE 13]
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After review of the data, 4,143 mandible fractures were identified. 1,057 of these fractures were not included in this review as their ICD-9 codes were coded as multiplesites unspecified. Therefore, 3,086 mandibular fractures were evaluated in this data subset.
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Like Fridrich et al [2], the most common site of fracture in this review was the mandibular angle (28.5%). The second most common site of fracture was the mandibular symphysis (21.4%). Other sites of fracture included the condyle/subcondyle (17.6%), body (17.5%), ramus (4.0%), alveolus (2.5%) and coronoid (1.1%). Multiple unspecified comprised the remaining fractures (7.4%). When mandibular fractures are categorized by mechanism, it becomes clear that a correlation exists between the mechanism, direction of force and type of fracture. As indicated earlier, low-velocity blunt mechanisms comprised the largest number of fractures in this study (2,328 fractures). Of the fractures resulting from low-velocity blunt mechanisms (interpersonal violence, sports-related injury, falls or struck by falling object), the mandibular angle was the most common site of fracture (31.49%). This is expected when one considers that the
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majority of low-velocity blunt injuries are the result of interpersonal violence. A blow to the side of the face as occurs when one is struck with largely will result in a strike against the mandibular angle. This was followed by fractures of the symphysis (21.26%), body (17.70%), and condyle/subcondyle (16.07%).
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High-velocity blunt mechanisms (motor vehicle collisions, motorcycle collisions, motor pedestrian collisions) resulted in a greater number of condylar fractures (25.4%) followed by symphysis fractures (22.8%) when compared to other sites. This may be expected when considering the vector of force often applied to the mandible during these collisions is largely in an anterior-posterior direction. The initiation of force is at the chin with transference posteriorly to the condyles.
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High-velocity penetrating mechanisms (firearms) reflected what we consider to be a non-anatomic pattern of injury. More specifically, the patterns of injury are more significantly affected by the properties of the projectile than the biomechanical properties of the mandible. This is expected considering that bullets travel in a random fashion as they ricochet off bones and are redirected through the tissues. These injuries resulted commonly in mandibular body fractures (24.0%) followed by symphysis (16.5%), angle (15.7%), condyle/subcondyle (8.3%), ramus (9.1%), coronoid (3.3%) and alveolus (0.8%) fractures.
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Low-velocity penetrating mechanisms (knife) bared a more predictable pattern as those areas of the mandible more readily exposed to stab injuries were most commonly affected. The most common sites of fracture in these injuries were the mandibular symphysis (21.4%), body (14.3%), angle (14.3%) and ramus (14.3%). This was followed by condyle/subcondyle (7.1%) and alveolus (7.1%). No fractures of the coronoid were reported.
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In each category (low-velocity blunt, high-velocity blunt, low-velocity penetrating, highvelocity penetrating), a number of fractures were excluded due to their classification in ICD-9 as “multiple-sites unspecified.” As expected, the largest number of unspecified fractures occurred in the low-velocity blunt category (156 fractures) as this was the largest sample (2,328 fractures). This indicates that 6.7% of this data is unusable in this type of study due to an inability to classify location. The largest percentage of fractures unclassified was found in high-velocity penetrating (27 fractures or 22.3%) trauma. This is expected given the high-level of destruction and comminution frequently characteristic of these types of injuries. There is often a higher number of lifethreatening co-morbidities requiring immediate management and resulting in less attention to coding of non-life threatening injuries. High-velocity blunt mechanism required exclusion of 6.9% of the total number of fractures (43 fractures) while lowvelocity penetrating required exclusion of 21.4% (3 fractures). Fracture Patterns According to this review just under half of the fractures were at a single site (49.6%). Mandibular fractures with a fracture at more than one site accounted for just over half
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of the fractures (50.4%) with a large number being two sites (34.3%), followed by three (4.8%) four (0.85%) and five sites (0.1%).
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There were a total of 4,143 fractures in 2,828 patients in this study, averaging 1.47 fractures per mandible. The highest number of fractures occurred at the mandibular angle (1123), followed by the mandibular symphysis (882), condyle/subcondyle complex (761), body (695) and ramus (225). It is the opinion of the authors that a specific association between different locations of fractures is an important consideration when performing clinical assessment of a patient with a mandible fracture. Knowledge that one particular type of fracture may be more likely with a fracture at another location can aide in diagnosis. To our knowledge, this is the first study to address the association between particular sites of mandibular injury.
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According to this study, condyle fractures were most frequently associated with concomitant symphysis fractures (51.9%), followed by mandibular body (27.4%), angle (11.8%), ramus (4.8%), alveolar (2.6%) and coronoid fractures (1.4%). Clearly, a correlation exists between mandibular condyle and symphysis fractures. When one considers that the direction of force applied to the mandible to result in a fracture of the mandibular symphysis is transmitted to the condylar region, this association is anatomically predictable. As a note, there was no way using ICD-9 coding to associate bilateral condyle fractures as coding does not differentiate between the right and left condyle.
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As previously mentioned, it is expected that force applied to the anterior mandible would result in a transmission of the force posteriorly. The mandibular ramus is no different. Like the mandibular condyle, the ramus is most often associated with symphysis fractures (36.7%), followed by mandibular body (30.2%), condyle/subcondyle complex (18.3%), angle (5.5%), coronoid (5.5%) and alveolus (3.7%). Again, when considering direction of force this may be expected.
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According to our results, the mandibular angle was most often associated with concomitant symphysis fractures (47.3%). This was followed by mandibular angle and body fractures (41.0%), condyle (9.3%), ramus (1.1%), alveolar (0.7%) and coronoid fractures (0.3%). The mandibular body is most often associated with concomitant angle fractures (52.5%) followed by condyle fractures (27.7%). Other associated fractures included the mandibular symphysis (10.2%), ramus (8.0%), coronoid (0.7%) and alveolus (0.7%). The mandibular symphysis is most often associated with concomitant angle fractures (44.0%) or condylar complex fractures (38.2%). Other associated fractures include the mandibular body (7.4%), ramus (7.1%), alveolus (2.6%) and coronoid (0.5%). When examining alveolar process fractures, according to our data, the practitioner should be wary of the possibility of concomitant injury to the mandibular body (40.5%) and condyle (29.7%). This is followed by the mandibular ramus (10.8%), angle (10.8%)
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and symphysis (8.1%). No association existed between alveolar process and coronoid fractures according to our data.
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In comparison with the previously published largest study (1) there are some similarities and differences with our contemporary review. In both cases, the peak month of mandibular fractures was July at approximately 10%. Assaults were the main cause of the majority of fractures in both studies (48.15% in 1985, vs. 62% in 2014); however, our study showed a higher incidence of motor vehicle accidents than the 1985 study (24.25 to 15%). Regarding low velocity blunt injuries, which included assaults, our study showed that while angle fractures comprised a similar percentage (31.49% in 1985 to 30.6% in 2014), there were significant differences in condylar, body, and symphyseal fractures (24.3, 32.8, and 7.1% in 1985 vs. 16.07, 17.7, and 21.26% in 2014). Comparing the high velocity blunt injuries (MVC), it is clear that differences exist regarding fractures of the condyle, angle, body, and symphysis (34.1, 10.9, 34.8, and 11.7% in 1985 vs. 25.4, 20.1, 15.1, and 22.8% in 2014). Considering the samples size for both studies is comparable (3462 in 1985 vs. 4143 in 2014), these differences demonstrate changes in fracture patterns over the last 25 years.
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A weakness of the study is the inability to identify completely isolated mandibular fractures due to the limits of the ICD-9 coding system. For instance, a condyle fracture can be coded with ICD-9 data as a condylar fracture but we are not able to report with certainty that the condyle was not associated with another fracture at the same anatomic location (i.e. bilateral condyles) as we are not in possession of the modifier codes used to bill for fractures at the same anatomic location but differentiated on laterality (right vs. left). The same can be said with the ramus, angle, body and symphysis. We are unable to report on the incidence of bilateral condyle, ramus, angle, body or symphysis fractures. It is the author’s opinion that although this is a limitation in our study design, the large number of patients allows for some generalizations and can be used as a gauge when calculating general percentages of isolated fractures.
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Epidemiologic studies of various conditions are useful when properly utilized. General conclusions in regards to patterns of injury, associated co-morbidities, and treatment require classification and stratification based on certain variables. In the case of mandibular fractures the mechanism of injury appears to be an important point of stratification in regards to injury pattern, and more importantly has a bearing on the type and number of associated injuries. The surgeon should take into account the mechanism of injury and vector of force when evaluating patients with mandibular fractures. Further study will stratify mechanism of injury for patients presenting with mandibular fractures and correlation with other more serious injuries including cervical spine and vascular injuries.
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Acknowledgments: The authors would like to gratefully acknowledge the contributions to this article and dedicate this review to the memory of Robert V. Walker DDS (19242011).
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References
1. Ellis E, 3rd, Moos KF, el-Attar A: Ten years of mandibular fractures: an analysis of 2,137 cases. Oral Surg Oral Med Oral Pathol 1985;59:120
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2. Gutta R, Tracy K, Johnson C, James LE, Krishnan DG, Marciani RD: Outcomes of mandible fracture treatment at an academic tertiary hopital: a 5-year analysis. J Oral Maxillofac Surg 2014;72:550-558.
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3. Naveen SA, Naveen SV, Hegde N, et al.: The pattern of the maxillofacial fractures – a multicenter retrospective study. J Craniomaxillofac Surg 2012;40(8):675
4. Cbalag MS, Wasiak J, Andre NE, Tang J, et al.: Epidemiology and management of maxillofacial fractures in an Australian trauma centre. J Plast Reconstr Aesthet Surg 2014;67(2):183
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5. Van Hout WM, Van Cann EM, Abbink JH, Koole R: An epidemiological study of maxillofacial fractures requiring surgical treatment at a tertiary trauma centre between 2005 and 2010. Br J Oral Maxillofac Surg 2013;51(5):416
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6. Martins MM, Homsi N, Pereria CC, Jardim EC, Garcia IR: Epidemiologic evaluation of mandibular fractures in the Rio de Janeiro high-complexity hospital. J Craniofac Surg. 2011;22(6):2026
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7. Simsek S, Simsek B, Abubaker AO, Laskin DM: A comparative study of mandibular fractures in the United States and Turkey. Int J Oral Maxillofac Surg 2007;36(5):395. 8. Martinez AY, Como JJ, Vacca M, Nowak MJ, Thomas CL, Claridge JA: Trends in maxillofacial trauma: a comparison of two cohorts of patients at a single institution 20 years apart. J Oral Maxillofac Surg 2014;72:750 9. Fridrich KL, Pena-Velasco G, Olson RA: Changing trends with mandibular fractures: a review of 1,067 cases. J Oral Maxillofac Surg 1992;50:586 10. King RE, Scianna JM, Petruzzelli GJ: Mandible fracture patterns: a suburban trauma center experience. Am J Otolaryngol 2004;25:301
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11. Olson RA, Fonseca RJ, Zeitler DL, Osbon DB: Fractures of the mandible: a review of 580 cases. J Oral Maxillofac Surg 1982;40:23
FIGURE 4: Ramus fractures (N:109) TABLE 6: Ramus fractures (N:109) FIGURE 5: Angle fractures (N:526) TABLE 7: Angle fractures (N:526) FIGURE 6: Symphysis fractures (N:565) TABLE 8: Symphysis fractures (N:565)
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FIGURE 7: Body fractures (N: 411) TABLE 9: Body fractures (N: 411)
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FIGURE 3: Condyle/Subcondyle fractures (N: 832) TABLE 5: Condyle/Subcondyle fractures (N: 832)
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FIGURE 1. Incidence of fracture by age TABLE 1. Age by decade TABLE 2. Fractures by month TABLE 3. Fracture distribution by location FIGURE 2. Number of mandibular fractures by site TABLE 4. Number of mandibular fractures by site
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FIGURE LEGEND
FIGURE 8: Alveolar fractures (N: 37) TABLE 10: Alveolar fractures (N: 37)
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TABLE 11: Mechanism of Injury: N=2828 TABLE 12: Mechanism of Injury subdivided - Mechanism not specified excluded (N:2,041) TABLE 13: Anatomic distribution of mandible Fractures by Mechanism
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FIGURE 9: Mandible fractures by mechanism of injury FIGURE 10: Low velocity blunt (N: 2,328) FIGURE 11: High velocity blunt (N: 623) FIGURE 12: High velocity penetrating (N: 121) FIGURE 13: Low velocity penetrating (N: 14)
TABLES
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Table 1: Age by Decade Decade 0-10: 11-20: 21-30: 31-40: 41-50: 51-60: 61-70: 71-80: 81-90: Total:
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0.78 20.83 33.31 23.37 14.43 4.81 1.41 0.78 0.28 100.00
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Table 2: Fractures by Month Month January February March April May June July August September October November December
% 22 589 942 661 408 136 40 22 8
Patients 173 161 212 209 217 223 270 248 223 220 192 197 2545
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Table 3: Fracture Distribution by Location Location Angle Symphysis Condyle/Subcondyle Body Multiple Sites Unspecified Ramus Alverolar Border Coronoid Total
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% 1120 882 761 696 295 225 122 42 4143
27.0 21.3 18.4 16.8 7.1 5.4 2.9 1.0 100.00
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Table 4: Number of Mandibular Fractures by Site Site(s) N 1 Site 1402 Multiple Sites 1426 2 Sites 969 3 Sites 135 4 Sites 24 5 Sites 3 Multiple Sites Unspecified 295
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Table 5: Condyle/Subcondyle Fractures (N: 832) and Incidence of Fractures in a 2nd Site Coronoid Process 1.4% 12/832 Ramus 4.8% 40/832 Angle 11.8% 98/832 Body 27.4% 228/832 Alveolus 2.6% 22/832 Symphysis 51.9% 432/832
% 49.58% 50.42% 34.26% 4.77% 0.85% 0.11% 10.43%
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Table 6: Ramus Fractures (N: 109) and Incidence of Fractures in a 2nd site Condyle/Subcondyle 18.3% 20/109 Coronoid Process 5.5% 6/109 Angle 5.5% 6/109 Body 30.2% 33/109 Alveolus 3.7% 4/109 Symphysis 36.7% 40/109
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Table 7: Angle Fractures (N: 526) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 9.3% 49/526 Coronoid Process 0.3% 2/526 Ramus 1.1% 6/526 Body 41.0% 216/526 Alveolus 0.7% 4/526 Symphysis 47.3% 249/526
Table 8: Symphysis Fractures (N: 565) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 38.2% 216/565 Coronoid Process 0.5% 3/565 Ramus 7.1% 40/565 Angle 44.0% 249/565 Body 7.4% 42/565 Alveolus 2.6% 15/565
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Table 9: Body Fractures (N: 411) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 27.7% 114/411 Coronoid Process 0.7% 3/411 Ramus 8.0% 33/411 Angle 52.5% 216/411 Alveolus 0.7% 3/411 Symphysis 10.2% 42/411
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Table 10: Alveolar Fractures (N: 37) and Incidence of Fractures in a 2nd Site Condyle/Subcondyle 29.7% 11/37 Coronoid Process 0% 0/37 Ramus 10.8% 4/37 Angle 10.8% 4/37 Body 40.5% 15/37 Symphysis 8.1% 3/37
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Table 11: Mechanism of Injury, N=2828 High Velocity High Velocity Low Velocity Low Velocity Not Specified Blunt Penetrating Blunt Penetrating Injuries 563 141 1325 12 786 19.9% 5.0% 46.9% 0.4% 27.8%
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Table 12: Mechanism of Injury Subdivided (Mechanism Not Specified Excluded), N=2041 Interpersonal Sports Fall Motor Motor Motor Firearm Knife Conflict Vehicle Pedestrian Cycle Collision Collision/Bicycle Collision 968 92 198 495 67 68 141 12 47.43% 4.51% 9.70% 24.25% 3.28% 3.33% 6.91% 0.59%
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Symphysis Alveolar Border Multiple Unspecified
21.26% 1.68% 6.7%
3 1 3
21.4% 7.1% 21.4%
142 37 43
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22.8% 5.9% 6.9%
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16.5% 0.8% 22.3%
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20 1 27
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Table 13: Anatomic Distribution of Mandibular Fractures by Mechanism High Velocity Low Velocity High Velocity Low Velocity Penetrating Penetrating Blunt Blunt Location N=121 % N=14 % N=623 % N=2328 Condyle/Subcondyle 10 8.3% 1 7.1% 158 25.4% 374 Coronoid 4 3.3% 0 0% 6 1.0% 25 Ramus 11 9.1% 2 14.3% 16 2.6% 94 Angle 19 15.7% 2 14.3% 125 20.1% 733 Body 29 24.0% 2 14.3% 96 15.4% 412 495 39 156
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