Neck Trauma Deaths in Brazil : Review of 541 Cases

Neck trauma is associated with high morbidity and mortality. To establish the profile of death by neck trauma in the metropolitan area of Belo Horizonte (BH), Brazil, fatal cases subjected to necropsy at the Forensic Medicine Institute of BH 2006 to 2012 were evaluated. A total of 541 necropsy reports were analyzed; most victims were male (82%), single (70%) and non-white (72%). Almost half of the victims were under 30 years old (47%). Penetrating neck trauma was the most prevalent injury (74%), mainly caused by firearm projectiles (54%), and most cases were of homicide victims (67%). Alcohol consumption before death and positive drug tests were found in almost half of the cases (42% and 45%, respectively). Establishing the sociodemographic and behavioral profile of victims as well the intrinsic characteristics of this type of trauma are potentially relevant for identifying the highrisk population and for elaborating intervention strategies.


Introduction
Neck injuries are an important cause of trauma-related hospital admission and death 1 , and these injuries include several mechanisms that account for death, such as respiratory failure, bleeding, and spinal cord injury 1,2 .
Neck trauma injuries are classified as penetrating and non-penetrating.
Open and blunt neck injuries are usually caused by different mechanisms.
Gunshot wounds and stab wounds are the main causes of penetrating neck trauma in the United States and Brazil 4,5,6 .In turn, the main mechanism of non-penetrating neck trauma is blunt force, such as that in motor vehicle crashes, falls, and diving into shallow water 5,6 .
Despite the relevance of neck trauma, few studies have sought to elucidate the epidemiological profile of fatal victims.This study was undertaken to address this gap, with an additional aim to establish comparisons between deaths due to gunshot wounds and sharp force injury.To the best of our knowledge, no study has been performed in Brazil regarding the specific characteristics of the victims of fatal neck trauma.

Methods
The present retrospective study analyzed deaths due to neck trauma for cases subjected to necropsy at the Forensic Medicine Institute of Belo Horizonte (Instituto Médico-Legal de Belo Horizonte -IML/BH) from January 2006 through December 2012.Located in the capital of the state of Minas Gerais, the IML/BH is a government agency affiliated with the Civil Police and is in charge of the medical investigation of violent deaths in the state capital and most counties in the metropolitan area of Belo Horizonte.In Brazil, a federal law requires a forensic necropsy in all cases of violent death.Belo Horizonte has the sixth largest population in Brazil and includes 2,502,557 inhabitants according to 2015 estimates 7 .The metropolitan area of Belo Horizonte has the third largest population in the country, estimated at 5,829,921 inhabitants in 2015; its total area is 14.979.1 km 2 , and the gross domestic product was estimated at BRL 188,541.7 million 7 in 2013.

L. S. Bordoni et al.
The deaths analyzed in the present study were directly related to neck trauma.
Cases with technical errors in the corresponding reports or a non-definable trauma type were excluded from the study, as were cases in which death was due to trauma to body areas other than the neck or to asphyxia by neck compression (hanging, strangulation).
The information in the necropsy reports was exported to Microsoft Excel ® , and the fields were re-encoded to represent the following variables: year, month, day of the week, gender, age, age range, skin color, civil status, city of residence, employment status, educational level required for occupation, manner of death, provenance of the victim, medical care received before death, medical procedures performed, blood alcohol content testing (and results) and drug testing (and results) 8 .
Victims were considered as having received medical care when they had been referred from healthcare services and/or had a medical report.
Statistical analysis was performed using IBM SPSS version 20.0.Frequencies and measures of central tendency were calculated.Chi-square and Fisher's exact tests or mean rank tests (such as the Kruskal-Wallis test) were performed to investigate possible associations.The significance level was set to α=0.05, and the confidence interval was set to 95%.

IML-BH authorized the present study, which was approved by the Research
Ethics Committee of the Hospital Foundation of the State of Minas Gerais, protocol no.31115314.5.0000.5119.
The mean age of the victims was 34 years old, with a standard deviation of 16 years (varying from 4 to 82 years old).Most victims were employed (73%) and had a requirement of complete secondary education for their occupation (68.2%).

Penetrating neck trauma profile: gunshot wounds vs. sharp force injuries
Of the 541 cases of neck trauma, 404 were of the penetrating type (74.3%), with most caused by gunshot wounds (219 cases, 54.12%) (Table 3).For gunshot wounds, the mean number of entrance wounds was 1.4, and in the case of sharp force trauma, the mean number of wounds to the neck was 2.1.
Most cases were male (85.1%); this proportion was higher in the case of gunshot wounds (91.3%, p<0.001) than in the case of sharp force trauma (77.8%).
Consequently, the proportion of women was significantly higher among the cases of sharp force trauma (22.2%, p<0.001) (Table 3).Brown-skinned individuals (61.6%) predominated among the penetrating neck trauma victims.Among the victims who died due to sharp force trauma, the proportion of brown-skinned individuals (69.2%) was higher than that of black individuals (8.2%).The same pattern was found among the gunshot wound cases (Table 3).More than 75% of the victims were single; this proportion was higher among the victims with gunshot wounds (80.8%).Most individuals (52.2%) resided in the counties composing the metropolitan area of Belo Horizonte, but not in the state capital (Table 3).Most victims were economically active (73.5%) and had a complete secondary education as an educational requirement for their occupation (68.5%).
Relative to the manner of death, homicide prevailed (87.9%), and the largest proportion of corpses was found on the street (38.1%) (Table 4).Most victims (73.3%) had not received medical care before death, and only 9.7% exhibited signs of having been subjected to medical procedures, such as venous access, drains, tracheal intubation, surgery, or suturing.Signs of medical care were significantly (p<0.001) more prevalent among the individuals with sharp force trauma (34.2%) (Table 4).4).Among the cases that tested positive for drugs, cocaine was the most frequently found drug (44.1%),followed by marijuana-cocaine combinations (34.6%) and marijuana alone (16.8%).

Discussion
The relationship found between neck trauma and male gender, especially in the case of gunshot wounds, might be attributed to the more aggressive behavior of men than women.Men are more frequently either victims or perpetrators of homicides, use firearms as instruments of aggression more often, and consume more alcohol and drugs, which may increase aggressiveness and high-risk behaviors [9][10][11][12] .Concerning the high proportion of female victims of sharp force neck trauma, crimes against women are frequently motivated by passion and usually occur in the home environment, where "cold weapons" are easily accessible to perpetrators 12 .Neck and head injuries are significant markers for intimate partner violence 13,14 .In a 10-year period study of adult femicide victims carried out in Taiwan, the most common site of injuries in the intimate partner group was the neck 14 .And a study conducted in Norway with victims of homicide by sharp force found that 91% of the females had been killed inside their home 15 .
Young and single people, who were more prevalent in the present study, are more predisposed to violence because many of them have not yet started a family of their own or do not have a safe socioeconomic status and are therefore more prone to become involved in high-risk situations, particularly in developing countries such as Brazil [16][17] .Concerning penetrating trauma, the proportion of non-single (married, in stable unions, etc.) individuals and the mean age of gunshot wound victims were lower than those of sharp force trauma victims.These findings might be attributed to the involvement of young and single people with crime (mainly drug trafficking and organized crime) and consequently with firearms, especially in the Brazilian urban peripheral areas [16][17][18] .The most striking characteristic of the epidemiological pattern of homicide in Brazil (the main circumstance of death in the present study) is its occurrence among an increasingly younger population [19][20] .Most of the victims subjected to necropsy at IML-BH resided in the metropolitan area of the state capital.
In general, the peripheral areas of the large Brazilian cities exhibit higher levels of crime, which corroborates the high index of homicide found in the present study 21 .
Non-white (brown-skinned and black) victims were the most prevalent in the present study.In Brazil, such individuals tend to belong to the less favored social classes and exhibit higher social risk for violent death 11,22 .Young black Brazilians have 2.5 times higher odds of being murdered than white youths 11 .While the absolute number of homicides among the Brazilian young white population is decreasing, that of young blacks is increasing 18 .In the present study, the number of blacks who died from gunshot wounds was higher than that of cases of death by sharp force trauma, which suggests a relationship among a socially vulnerable population, criminality, and the use of firearms.
Most of the deaths assessed in the present study were due to penetrating neck trauma, which is directly related to interpersonal violence.This was also evidenced in other studies and is related to the fact that the rates of homicide in Brazil are high 6,11,18 .Firearm homicides were more prevalent in the present and other studies 16 .However, the main mechanism of penetrating trauma varied among different studies, mainly because they were conducted in different places.For example, in São Paulo, the most populous Brazilian city, the prevalence of deaths by penetrating neck trauma due to gunshot wounds is higher 22 , whereas in the United Arab Emirates a higher prevalence of neck trauma by sharp force occurs 21 .In Brazil, since the beginning of the 1990s, the death by homicide rate per 100,000 habitants has surpassed the rate of deaths by traffic accidents, a fact that corroborates the data relative to the population assessed in the present study, as blunt trauma (more closely related to traffic accidents) ranked second in prevalence 6 .
Approximately 50% of gunshot wounds in the neck have significant injuries to vital structures, in comparison with only 10% to 20% of the stab wounds in the same region 1 .The damaging power of "cold weapons" is lower than that of firearm projectiles, and thus, a larger number of stab wounds are usually needed to cause death; this fact corroborates the results of the present study, in which the mean number of gunshot wounds was lower than wounds caused by "cold weapons".In the neck, where major blood vessels and the airways are relatively unprotected, a low number of wounds is needed to cause death, which accounts for the fact that the mean number of wounds found in the present study (only two) was lower than the rate described in other studies (3 to 4 wounds, on average), in which most victims presented more than one affected body region [23][24][25] .
The low education level required for the job performed by most victims in the present study, together with the high prevalence of homicide found, corroborates the observation made by several studies that the education level may be inversely proportional to the homicide rate in a given population 11,16,22,26 .Low education levels (less than four years of formal schooling) are associated with higher risk of death by homicide in all the Brazilian states 16 .
As only the smallest proportion of the victims assessed had received medical care, it is possible that neck trauma is associated with high immediate and precocious mortality.The increased severity of injury is further supported by the fact that a relevant percentage of the corpses had been transported to IML/BH directly from the street, suggesting that there was no time for the victims to be taken to a healthcare facility.In the case of penetrating trauma, the percentage of victims who received medical care and procedures was even lower, the reason being that this type of injury is associated with greater odds of damage to vital structures, such as large blood vessels and the airways.These data reinforce the fact that the best social approach to neck trauma, especially in the case of penetrating injuries, is its prevention, as once it occurs, the rate of immediate mortality is high.
Blood alcohol content and drug testing were positive in a considerable number of cases.The relationship between alcohol intake and neck trauma has previously been emphasized in several studies 3,10,17,19 .More than half of the homicides in the United States are related to the consumption of alcohol or psychoactive drugs 4 .
Almost half of the victims subjected to necropsy at the Forensic Medicine Institute of São Paulo in 2015 tested positive for blood alcohol, and consumption was higher among the victims of sharp force homicide 10 .The data relative to IML/BH are similar to those of São Paulo, as the largest proportion of cases was positive for alcohol and significantly higher blood alcohol concentrations were found among the victims of penetrating neck trauma by sharp force.The drugs most often used by the neck trauma victims were cocaine and marijuana, which are the illegal substances that are more widely consumed in Brazil 26 .Although some data indicate that marijuana is more widely used than cocaine in the country, in the present study, the drug most frequently found among the victims was cocaine, the chemical properties and neurological effects of which are more closely related to violent attitudes and actions and thus might also be more strongly associated with death by external causes 27 .As some studies show, violence associated with use of "cold weapons" or firearms might be related to the use of psychoactive drugs 18,19,27 .
The fact that deaths due to neck trauma occurred more often on Saturdays and Sundays might be related to the prevalence of penetrating injuries, especially those caused by firearms, in which case homicide is the main circumstance of death 27,28 .In addition, in Brazil, most jobs do not require full-time work on weekends, and employees might spend their free time consuming large amounts of legal or illegal drugs, a behavior associated with aggressiveness and criminality 10,11,18 .
However, from the occupational perspective, most of the victims analyzed in the present study were economically active, which highlights the economic and social damage associated with neck trauma resulting in disability or death.Brazil is currently undergoing a phase of demographic transition, with increasing population aging, which in combination with the loss of economically active individuals is a problem with serious economic and social impacts that makes measures for primary prevention of neck trauma even more necessary 29 .As neck trauma is associated with increased morbidity and mortality, establishing the sociodemographic and behavioral profile of victims as well of the intrinsic and related characteristics of this type of trauma is highly relevant for identifying the high-risk population and for the elaboration of intervention strategies.
The main limitations of the present study include the fact that data collection was performed in a specific geographical area; therefore, extrapolation of the conclusions requires caution; the operation of Forensic Medicine Institutes involves particular administrative and technical aspects that differ among the various Brazilian states and also among different countries; information was collected from secondary sources; and the data corresponding to the variables assessed were not recorded in all of the analyzed reports.

Conclusion
The sociodemographic profile of the victims of neck trauma corresponded to male, young, non-white, and economically active individuals.Penetrating trauma was the most prevalent trauma type, followed by blunt injury.Among the types of penetrating neck trauma, gunshot wounds were most prevalent.Homicide was the circumstance most often associated with neck trauma, and a large number of victims were under the influence of legal (alcohol) or illegal (cocaine and marijuana) drugs.

Figure 1 .
Figure 1.Seasonality of deaths due to neck trauma: year, month, and day of the week (IML/BH, 2006 a 2012).

Table 1 .
Sociodemographic characteristics of fatal neck trauma victims per type of trauma (IML/BH,

Table 2 .
Data related to death circumstances, provenance of the victim, medical care, medical procedures, blood alcohol content and drug testing of fatal neck trauma victims according to trauma type (IML/BH, 2006 a 2012).

Table 3 .
ComparisonMost victims were 18 to 39 years old (62.6%); the proportion of cases within this age range was higher among the group with gunshot wounds (66.7%) than in the group with sharp force trauma (57.8%).The largest difference between groups as a function of age range corresponded to victims over 50 years old (6.9% of gunshot wound cases and 15.7% of sharp force trauma victims) (Table3).The difference between the mean age of these groups was significant (p<0.001,29 years old of sociodemographic characteristics of fatal victims of penetrating neck trauma according to death-causing action (IML/BH, 2006 a 2012).[standarddeviation 12 years] among the gunshot wound victims and 34 years old [standard deviation 14 years] among sharp force injury victims).

Table 4 .
Comparison of death circumstances, provenance of the victim, medical approach, alcohol level and toxicology testing of fatal victims of penetrating neck trauma according to death-causing action (IML/BH, 2006 a 2012).