Epidemiological study of facial fractures at the Oral and Maxillofacial Surgery Service , Santa Casa de Misericordia Hospital Complex , Porto Alegre – RS – Brazil

Objectives: to investigate the incidence and etiology of face trauma with diagnosis of facial fracture treated at the Buccomaxillofacial Surgery and Traumatology Service of the Santa Casa de Misericórdia Hospital Complex in Porto Alegre. Methods: we conducted a cross-sectional, retrospective epidemiological study of 134 trauma victims with 153 facial fractures. Results: the male gender was the most affected (86.6%) and the incidence was higher in the age group from 21 to 30 years. The main etiology was assault (38.8%), followed by motor vehicle accidents (14.2%), motorcycle accidents (13.4%), falls (9%), road accidents (6.7%), sports accidents (5.2%), work accidents (5.2%), firearm injuries (4.5%) and cycling accidents (3%). The most frequent fractures were those of the zygomatic complex (44.5%), followed by fractures of the mandible (42.5%), maxillary bone (5.2%), nasal bones (4.5%) and zygomatic arch (3.3%). Conclusion: the fractures of the zygomatic complex and the mandible were the ones with the highest incidence in the facial traumas, having physical assaults as their main cause.


INTRODUCTION
T rauma is the public health problem with the greatest po- tential to be prevented and treated.Thus, understanding the cause and severity of maxillofacial lesions may contribute to the establishment of clinical and research priorities for the effective treatment and prevention of these injuries 1 .Trauma is among the leading causes of death and morbidity in the world, accounting for 7.4% to 8.7% of emergency care 2 .The increase in the level of life expectancy, urban growth and its forms of locomotion, unemployment crises and the consumption of alcohol and drugs in the different regions, alter the age, gender, etiology and frequency of facial lesions 3 .
Studies aimed at investigating the treatments and complications of facial trauma allow quantification and qualification of such lesions' sequelae 4 .The main causes of facial fractures include auto accidents and assaults.Other causes are falls, sports accidents and accidents at work [5][6][7] .In some countries, the reduction of motor vehicle accidents by the introduction of safety measures and legislation to punish vehicle-driving irregularities has increased physical assaults and sports accidents to the condition of main agents causing traumatic buccomaxillofacial injuries 8 .Thus, it is evident the need for campaigns to prevent the main etiological agents of facial trauma, to contribute to the reduction of this type of occurrence.
The objective of this study is to determine the Results: the male gender was the most affected (86.6%) and the incidence was higher in the age group from 21 to 30 years.The main etiology was assault (38.8%), followed by motor vehicle accidents (14.2%), motorcycle accidents (13.4%), falls (9%), road accidents (6.7%), sports accidents (5.2%), work accidents (5.2%), firearm injuries (4.5%) and cycling accidents (3%).The most frequent fractures were those of the zygomatic complex (44.5%), followed by fractures of the mandible (42.5%), maxillary bone (5.2%), nasal bones (4.5%) and zygomatic arch (3.3%).Conclusion: the fractures of the zygomatic complex and the mandible were the ones with the highest incidence in the facial traumas, having physical assaults as their main cause.We classified fractures of the facial skeleton into mandibular bone, zygomatic complex, maxillary bones, nasal bones and zygomatic arches 9,10 .We included orbital fractures in the subgroup of fractures of the zygomatic complex, as it participates in the orbit floor, as well as in its lateral wall 11 .We included dento--alveolar fractures in the group of fractures of the bone corresponding to the fractured arch, and we excluded the exclusively dental fractures from the statistics.

Keywords
We analyzed the data collected in the medical charts and transposed them to specific records, being one record for each chart.We extracted the following data: patient identification, age group, gender, etiological agent of facial fracture and facial fracture classification.We performed a descriptive analysis of the data, calculating frequency and percentage for categorical variables, and mean and standard deviation for quantitative variables.To identify the factors associated with the trauma site, we used the ANOVA test with Tukey's multiple comparisons for the quantitative variables and the chi-square or Fisher's exact test for categorical variables.We analyzed data in the SPSS 12.0 software and the minimum level of significance was 5%.

RESULTS
Regarding the profile of the patients treated, the male gender was the most affected, representing 86.6% of face fractures, when compared with the female one (13.4%),establishing a ratio of approximately 6:1.Regarding the distribution of frequencies and percentages referring to the age groups, we verified that the most affected age group was from 21 to 30 years old, with 41 cases (30.6%), followed by the age  3).Regarding the number of facial fractures in both males and females, the mandibular bone was the most affected.None of the types of facial fractures assessed in this study showed gender preference, according to the chi-square and Fisher's exact tests.
Table 4 shows the distribution of facial fractures according to age group.We found no significant difference in this assessment.

DISCUSSION
The results of an epidemiological survey of face traumas of a population should be evaluated accor-ding to a series of variables related to individuals and the region studied.Ellis et al. 12 point out that the cause of the lesion and the geographical area where it occurred, the socioeconomic level of the population, the study period and the population mobility can alter results and show the most varied trauma presentations.Data obtained in this study revealed that the two main etiological factors of facial fractures are assaults and traffic accidents.Three decades ago, the studies pointed to motor vehicle accidents as the main cause of facial trauma 9,10 .
However, current research in Brazil shows an increasing participation of physical assault as an etiological factor of facial trauma due to the increase in urban violence, which, among other problems, is associated with the socioeconomic and emotional conflicts to which many individuals are subjected, especially the youngest 6,11 .
Public actions such as speeding control and severe punishment for drunk drivers, as well as the introduction of safety devices such as seat belts and helmets, air bags, side protection bars and the evolution of the automobile industry as a whole are responsible for decreasing the number of facial traumas due to motor vehicle accidents 10,13 .Our results are in agreement with other evidence in the literature reporting that assaults were the main cause of facial fractures 3,11,[14][15][16][17][18][19] .In the present study, assaults resulted in 38.8% of the cases, excluding gunshot wounds.
The second most involved etiological agent was automobile accidents, accounting for 14.2% of facial fractures, being in accordance with the literature.When studied in conjunction with run-overs, motorcycle accidents and cycling accidents, that percentage rises to 37.3%.These data show a worrying reality, since even when all types of traffic accidents were present, the facial trauma index was still lower than that of assaults 16 .Other studies, however, still point car accidents as the most frequent etiological agent 3,20-23 .This may be due to the inclusion of patients who were victims of facial trauma in the eighties and nineties, when the use of protective equipment in vehicles was not mandatory, especially in Brazil 10,13 .
According to Adebayo et al. 5 , the etiologies of face traumas vary with the socioeconomic conditions of each region.Studies carried out in different regions report divergences regarding the main etiological factor.Thus, Thomson et al. 23 verified that most facial fractures were caused by falls and Subhashraj, Ramkumar and Ravindran 24 concluded that the motorcycle accident was the main etiological factor.In our study, these agents represented the fourth and third causes of facial fracture, respectively.Accidents at work were the etiological agent with the highest mean age (47 years), while sports accidents had the lowest one (24.86years).Fall is the main mechanism of trauma in the age group over 40 years, and is usually related to the presence of multiple diseases 9,19,25 .However, Macedo et al. 11 stated that the fall proved to be an important trauma mechanism at the extremes of age.Karyouti 26 reported that children are constantly engaged in sports activities and risky exercise, without the use of appropriate protective equipment and away from the supervision of those responsible, contributing to the increase in the number of facial fractures.Since the care for children in the facility where we conducted this study is restricted, we could not confront these data 6,27 .
Regarding age, the studied sample revealed that the highest prevalence of facial fractures occurs in the age group of 21 to 30 years and from 31 to 40 years, unlike other studies in which the predominant age group was from 61 to 70 years old 5,9,15,17,[20][21][22][23][28][29][30][31][32][33][34] . For Res et al. 14 , the most affected age group was 11 to 30 years.This is due to the fact that in this age group individuals are more exposed to the risk factors, since they are in full physical and professional activity 7 . Evdence in the literature reveals a high number of fractures and facial trauma caused by sports, among them soccer, hockey, rugby and wrestling, which brings into question the incentive to use personal protective equipment 7 .
However, there is great disagreement with the researched authors, the nose bone fractures being more prevalent in several studies 17,29,32 .As for Alvi, Doherty and Lewen 16 , orbital fractures were the most prevalent.
The relationship between the type of fracture and the etiology of trauma showed no difference in this study.Some works have found that most mandible fractures are the result of physical assault, traffic accidents, gunshot wounds, accidents with industrial workers and sports accidents 7,19 .According to Greenberg and Haug 25 , assaults cause more fractures of the mandible, zygomatic complex and nose bones, whereas motor vehicle accidents promote more fractures in the maxillary bones.
As in most studies, our work showed a predominance of facial fractures in men 5,9,11,15,20,34 .Thomson et al. 23 , however, identified the female gender as more prevalent.We observed a difference in etiology according to gender, in which men have more fractu-res due to assaults (42.2%), while women have more fractures due to run-overs (22.2%) and falls (27.8%).
Silva 34 emphasizes that trauma should not be seen only as a medical problem, but also a social and economic one.Costs incurred in providing care to victims by health workers, damage to property involved at the time of trauma, loss of wages and permanent or transient disabilities often lead to difficulties in the social reintegration of victims and their return to the job market.All these factors, added to the familiar incon-veniences and psychological wear and tear on patient care reveal a much greater repercussion of this disease, which deserves constant attention by health institutions that provide assistance to traumatized patients.This research provides data for a better understanding of the facial fractures' main etiological agents and the most affected bones in the studied population, being of fundamental importance for the planning, organization and improvement of care of such patients.
incidence and etiology of facial traumas with diagnosis of facial fractures seen at the Buccomaxillofacial Surgery and Traumatology Service (CTBMF) of the Holy Home of Mercy Hospital Complex of Porto Alegre, RS, Brazil.METHODS This work was accomplished after approval by the Ethics in Research Committee of the Holy Home of Mercy of Porto Alegre, under the protocol n° 460/09.Original Article A B S T R A C T Objectives: to investigate the incidence and etiology of face trauma with diagnosis of facial fracture treated at the Buccomaxillofacial Surgery and Traumatology Service of the Santa Casa de Misericórdia Hospital Complex in Porto Alegre.Methods: we conducted a cross-sectional, retrospective epidemiological study of 134 trauma victims with 153 facial fractures.

Table 1 .
Frequency and percentage of facial fractures according to etiological agent.
red in the zygomatic complex, 65 (42.5%) in the mandible, eight (5.2%) in the maxillary bone, seven (4.5%) in the nasal bones and in the zygomatic arch we recorded five fractures (3.3%) (Table

Table 2 .
Distribution of patients with facial fractures according to etiological agents and mean age.

Table 4 .
Distribution of facial fractures according to age group.

Table 3 .
Distribution of frequencies and percentages of facial fractures.