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Chinese Journal of Traumatology 2010; 13(1):3-9 . 3 .

Original articles

Spinal fractures resulting from traumatic

Heidari Pedram, Zarei Mohammad Reza, Rasouli Mohammad Reza, Alexander R Vaccaro and Rahimi-Movaghar Vafa*

【Abstract】Objective: To illustrate mechanisms of accidental falls (P<0.001). A total of 171 (27.6%) patients spine fractures and the pattern of spinal injuries character- had associated non-spinal injuries, of whom 127 had asso- ized by the major mechanisms in urban population of Iran. ciated extremity injuries, and 55 had head injuries. Thirty-six Methods: Data regarding spinal injuries including (5.6%) patients had spinal cord (SCI).The injury se- demographics, mechanism and level of spinal injury, abbre- verity score of the RTC group was significantly higher than viated injury score, associated injuries and final fate of the that of accidental falls (P=0.002). Fifteen (4%) patients died patients were extracted from the Iranian national trauma reg- of traumatic injuries. The rate of death was significantly istry database from 1999 to 2004. higher in RTCs compared with accidental falls (5.1% vs 2.1%, Results: A total of 619 patients with traumatic spine P=0.039). fractures were identified, of whom 68.5% were males. The Conclusions: The patterns of spinal fractures are simi- peak frequency of these injuries occurred in the 21-40 year lar to those reported from developed countries. RTCs tend age-group. Accidental falls and road traffic crashes (RTCs) to affect the younger age population and are associated were the most common mechanisms of spinal fractures (47.2% with a higher degree of associated injuries and mortality and 44.1%, respectively). RTCs tended to occur in younger than accidental falls. Therefore preventive strategies should patients compared with accidental falls. The most common be based on reduction of the number and severity of RTCs. spinal region for spinal fracture was the lumbar spine (53.63%). Key words: Accidents, traffic; Accidental falls; Spi- Cervical spine fractures were significantly more common in nal fractures; and injuries; Cross-sectional RTCs, while lumbar spine fractures were more common in studies; Retrospective studies Chin J Traumatol 2010; 13(1):3-9

raumatic injuries are the most common cause contributor to health care costs.1-3 Spine and spinal- of death among young people, a leading cause related injuries, which are common after traumatic Tof disability and years of life lost, and a major injuries, have the poorest functional outcomes and the lowest rates of return to work after injury among all major DOI: 10.3760/cma.j.issn.1008-1275.2010.01.001 organ systems.2 Orthopedic Department, Imam University Hospital, Tehran University of Medical Sciences, Tehran, Iran (Pedram H) The diagnosis of spinal injury is often delayed, and Sina Trauma and Surgery Research Center, Sina the treatment is not uniformly established. The delay in Hospital, Tehran University of Medical Sciences, Tehran, diagnosis may occur because of the lack of obvious Iran (Reza ZM, Reza RM, and Vafa RM) deformity on physical or radiographic examination.4-6 Emergency Department, Imam Khomeini As timely diagnosis of spinal injuries is paramount, it Hospital, Tehran University of Medical Sciences, Tehran, is advantageous to have accurate information about Iran (Reza ZM) Department of Orhtopaedics and Neurosurgery, Tho- which demographic groups are more likely to sustain mas Jefferson University and the Rothman Institute, spinal injury following trauma.7 Philadelphia, USA (Vaccaro AR) *Corresponding author: Tel: 98-915-3422682, Fax: 98- Regional differences in the patterns and causes of 216-6705140, E-mail: [email protected], v_rahimi injury have significant implications for prevention policies. @yahoo.com Prevention policies should be based on available re- This study has been performed in Sina Trauma and Surgery Research Center, Sina Hospital, Tehran Univer- gional data as making important decisions. Although sity of Medical Sciences, Tehran, Iran. information from developed countries is useful in gen- . 4 . Chinese Journal of Traumatology 2010; 13(1):3-9 eral terms, it is relatively ineffectual for policy develop- severity score (ISS) was computed from the sum of ment due to activity differences and cultural variances.8 squares of the highest AIS score in the three most se- Epidemiologic studies from developed countries have verely injured body regions. shown accidental falls to be the most common cause of spinal fractures, while motor vehicle injuries were the Statistical analysis was conducted consisting of second in occurrence.9 This may not be reflective of Student's t test, non-parametric tests including Mann- developing countries such as Iran, which, according to Whitney U test and Kruskal-Wallis test to compare some reports, has a high rate of injuries from RTCs.10,11 means and Chi-square testing of frequency data where Since there is such a great difference in the prevalence appropriate. The significance level was set at 0.05. Sta- of various causes of traumatic injuries between devel- tistical analyses of data were done using either SPSS oped courtries and developing countries, we proposed 14.0 (SPSS Inc, Illinois, USA) or STATA 10 (Statacorp, that the pattern of spine injuries might also be different Texas, USA). in urban areas of Iran. The pattern of has been relatively well defined;12-15 however, to the best RESULTS of our knowledge, there are few studies discussing the cause and pattern of spinal fractures following traumatic Of a total of 16 321 patients registered, 619 (3.48%) injuries in a similar population.16 had a traumatic spinal fracture to the spinal column, 424 (68.5%) were males and 195 (31.5%) females. The In this study, the pattern of spinal fractures follow- mean age of patients with spinal fractures was 38.4 ing trauma and the various factors influencing their years±16.8 years (range 3-80 years). The highest rate occurrence, and the final fate of the patients are of spinal fractures was observed in the 21-30 and 31-40 discussed. years age groups (23.3% and 23.4% of all spinal fractures, respectively). The distribution of spinal fractures accord- METHODS ing to sex among age groups is shown in Figure 1.

This study was a retrospective cross-sectional study Mechanism of injury which was performed using the data from Iran national The mechanisms of spine fractures and their fre- trauma registry database from August 1999 to Febru- quencies are summarized in Table 1. Accidental falls ary 2004. The data of this database were collected from was the most common mechanism of spinal fractures target hospitals in eight major cities of Iran. The data of (47.17%) and these fractures were most commonly due every patient who was admitted in these hospitals due to falls of less than 4 m (33.6% of all fractures). RTCs to trauma and had a hospital stay of more than 24 hours were the second most common mechanism of spinal were registered in the database. The data which were fracture (44.1%) and most patients in this category were extracted from the original database for this study in- car occupants (18.9% of all fractures). Cumulatively, cluded patients’ general characteristics, mechanism of the two mentioned mechanisms comprised more than trauma, levels and regions of spinal injury, associated 90% of all causes of spinal injuries. injuries, (AIS), duration of hos- pital stay, and final disposition/outcome. The type of The age of maximal prevalence of spinal fractures spinal injury and mechanism of accidents were coded differed among various mechanisms of injuries. Spinal according to the International Classification of Diseases, fractures most commonly occurred in the 31-40 year 9th revision (ICD-9). Region of spinal injury was divided age-group among patients who sustained injury due to by ICD-9 diagnostic codes and classified into upper a fall, while they were more common in the 21-30 year cervical (C1-C4), lower cervical (C5-C7), thoracic, lumbar, age-group in patients who incurred spinal fractures due and unspecified. In this report, the upper and lower cer- to RTCs (Figure 2). The frequency of spinal fractures vical regions were regrouped into a single cervical region. was the highest in the 21-30 year age-group in all sub- AIS scores were used to classify injury severity and groups of RTCs but in pedestrians who sustained spi- were assigned to all injuries (ICD-9-CM 800-904 and nal fracture the most commonly age group were those 910-959) noted in the diagnostic record of cases of in the range of 61-70 years (Figure 3). hospitalized patients with spinal fractures.17-19 Injury Chinese Journal of Traumatology 2010; 13(1):3-9 . 5 .

Figure 1 Figure 2 Fig Figure 1. The frequency of spinal fractures in age groups in both sexes. Figure 2. The frequency of spinal fractures in age groups in two major mechanisms of trauma. Figure 3. The frequency of spinal fractures in age groups in three major subgroups of RTCs.

Anatomic distribution Associated injuries Spinal fractures were categorized into three ana- Among all 619 patients, 171(27.6%) had associ- tomic regions, i.e. cervical, thoracic, and lumbar. The ated non-spinal cord injuries, of whom 144 (84.2%) had most common region of spinal fracture was the lumbar only one associated injury. Of all patients with associ- region (n=332, 53.63%), followed by the thoracic (n=141, ated injuries, 127 (74.3%) had associated extremity 22.78%) and then the cervical (n=119, 19.22%). Of 619 injuries, and 55 (32.2%) had head and neck injuries cases, 27 (4.36%) patients had multiple fractures of (Figure 6). Eighty (29.4%) patients with spinal fractures the thoracic and lumbar spine (n=25) and the cervical due to RTCs and 74 (25.4%) patients due to a fall had and lumbar spine (n=2). an associated injury (Figure 6). A total of 36 (5.6%) patients had spinal cord injury (SCI); 25 patients had In patients with single spinal fracture, there was a complete SCI while the remaining 11 patients suffered significant association between the two major mecha- incomplete SCI. Of all SCIs 29 were due to RTCs (18 nisms of fracture, i.e. RTCs or accidental falls and ana- patients) or accidental falls (11 patients) (Figure 6). There tomic region of fracture (P<0.001). Cervical spine frac- were 14 cervical SCIs, 5 thoracic SCIs, and 10 lumbar tures were more commonly seen in RTCs, while lum- SCIs. There was no significant difference (P=0.683) in bar spine fractures were more commonly seen in acci- the regional distribution of SCI in two major mecha- dental falls. Thoracic spine fracture had a similar fre- nisms of spinal fractures (RTC and accidental falls). quency in both mechanisms (Figure 4). The most com- mon level of spinal fractures was L1, followed by T12 and

L2 in the two major mechanisms of spinal injury; however, The ISS in the RTC group (median 8, mean 11.8, in every level of cervical spine fracture, a larger portion interquartile range 5-13) was higher than the ISS of the of fractures were due to RTCs as compared to falling accidental fall group (median 8, mean 8.5, interquartile injuries (Figure 5). There was no significant difference range 5-9), which was statistically significant (P =0.002). regarding region of spinal fracture between subgroups There was no significant difference among subgroups of fractures due to accidental falls while the difference of RTCs or between subgroups of accidental falls re- was significant among subgroups of RTCs (Table 2). garding mean ISS (P=0.283 and 0.22, respectively). Pedestrians and motorcyclists more commonly incurred lumbar spine fractures while car occupants more fre- Length of hospital stay quently had cervical spine fractures (Table 2). Among car The median duration of hospital stay for all patients occupants, front seat passengers sustained more inju- in this study was 4 days (mean 7.4, interquartile range ries to the lumbar spine in comparison to back seat 2-9). The length of hospitalization was not significantly passengers (38% vs 27%), while this trend was reversed different between the two major mechanisms of spine for thoracic spine fractures (22.8% vs 32.4%). However injury (P=0.345). Patients who sustained spinal frac- the difference in regional distribution of spinal fractures tures due to RTC injuries or accidental falls both had a was not significant between front seat and back seat median hospital stay of 4 days (mean=7.17, interquartile car passengers (P=0.41). range 2-7, and mean 6.91, interquartile range 2-9, . 6 . Chinese Journal of Traumatology 2010; 13(1):3-9 respectively). Among the subgroups of RTCs, the mean Final outcome duration of hospital stay was not significantly different Out of the total of 619 patients with spinal fractures (P=0.785), while this period was significantly longer in 96% (n=594) survived. Patients who sustained spinal accidental falls from >4 m heights (median 6, mean 8.79, fractures as a result of RTCs had a significantly higher interquartile range 3-12) compared with falls from <4 m rate of death due to injury than those had been injured (median 4, mean 6.14, interquartile range 2-7, P=0.001). due to falling (5.1% vs 2.1%, P=0.039). Due to small number of patients, comparison among subgroups of major mechanisms of trauma was not performed.

Figure 4 Figure 5 Figur Figure 4. The frequency of regions of spinal fracture in two major mechanisms of trauma. Figure 5. The frequency of levels of spinal fracture in two major mechanisms of trauma. Figure 6. The frequency of associated injuries in two major mechanisms of trauma.

Table 1. Frequency of spinal fractures according to mechanism of trauma

Trauma mechanism Patients (% of total) Accidental falls 292 (47.17) From >4 m heights 84 (13.57) From <4 m heights 208 (33.60) Road traffic crashes 273 (44.10) Car occupants 117 (18.90) Pedestrians 80 (12.92) Motorcyclists 60 (9.69) Other kinds of motor vehicle accidents 16 (25.85) Direct collision of a blunt object 45 (7.27) Self hanging 4 (0.65) Compression between two solid objects 2 (0.32) Assault 2 (0.32) 1 (0.16) Total 619 (100)

Table 2. Frequency of spinal fractures according to region of fracture in two major mechanisms of injury (road traffic crashes and accidental falls) Region of spinal fracture Mechanism of spinal fracture P value Cervical Thoracic Lumbar Road traffic crashes Car occupants (%) 44 (38.9) 29 (25.7) 40 (35.4) 0.01 Pedestrians (%) 13 (16.9) 20 (26.0) 44 (57.1) Motorcyclists (%) 16 (27.6) 12 (20.7) 30 (51.7) Accidental falls > 4 m (%) 7 (8.7) 21 (26.6) 51 (64.6) 0.84 < 4 m (%) 18 (9.1) 46 (23.2) 134 (67.7) Chinese Journal of Traumatology 2010; 13(1):3-9 . 7 .

DISCUSSION diverse frequencies of injury subtypes for each age subgroup,20,24 which are directly related to the local traffic As the results showed, the peak frequency of spi- situation, the mode of transportation used, and the nal fracture occurred in the 21-40 year age group, which population studied. Qi et al,24 in a study on Chinese was similar to the peak rate of spinal fractures in male population of Ningbo city, reported that motorcycle ac- patients. This similarity of distribution could be easily cidents were the most prevalent mechanism of injury described by the higher number of males registered as (33%) followed by pedestrian collision by motor vehicles compared to females which in turn increases the im- (24.9%) and bicycle accidents (23.5%). Hill et al 20 re- pact of the males’ data on the entire data collected. ported the highest rate of spinal fractures in pedestrian The age distribution of spinal fractures was also differ- collision by motor vehicles in a population-based study ent between the two major mechanisms of spinal frac- in Sydney, Australia. We found spinal fractures most tures in this study. The patients who had spinal frac- commonly occurred in car occupants. In Iran, the lack ture due to RTCs tended to be younger than the pa- of modern means of public transportation, especially in tients who had a spinal injury due to an accidental fall. large cities, motivates the usage of passenger cars for There was also a tendency for pedestrians to be of older transportation. Also due to low standards of car manu- age compared with car occupants or motorcyclist. This facturing and lack of strict regulations upon use of safety pattern of age distribution according to the mechanism measures, the probability of sustaining serious trauma of trauma was in concordance with the data obtained in vehicle collisions is fairly high. Most cars are not from developed countries.9,20 equipped with ABS brakes and air bags and people have no motivation to use safety belts. The total number of males in the current study was two times more than that of females. This is mainly In the present study, the majority of spinal fractures due to cultural constitution of the Iranian society, in were in the thoracolumbar region; this was due to the which women are involved in fewer social activities than fact that the majority of traumatic injuries were due to men, and women are not allowed to drive motorcycles accidental falls, pedestrian collisions and motorcycle and it is less likely that they drive cars. Therefore the accidents which cumulatively constituted around 70% rate of RTCs was much lower among women in this of all injuries. Previous studies have shown that lumbar study. Also the rate of accidental falls tends to be lower spine fractures have the highest frequency among all in female as they are unlikely to work in occupations regions of the spinal column following the previously that are in high risk for accidental falls like building cited mechanisms.9,20,25 It is worth mentioning that most construction. This pattern of sex distribution is also cervical spine fractures in car occupants confirm previ- reported in the studies describing patterns of spinal inju- ous reports.22,26 The biomechanics of the cervical spine ries following traumatic injuries in developed countries.21,22 allows for more cervical injuries following acceleration- Studies describing the pattern of spinal injury in the deceleration type traumas.27 general Canadian population reported a fairly equal per- centage for both sexes.9 The higher rate of osteoporotic In our population, the presence of associated inju- spine fractures compensated for the lower incidence of trau- ries (27.6%) was lower than the rates reported by Saboa matic spine fractures in females, especially in older ages. et al28 and Richard et al.23 Upper and lower extremity injuries were the most common associated injuries fol- RTCs are more prevalent in Iran compared with de- lowed by head injuries. Around 47% of patients in this veloped countries; however, similar to reports from de- study developed spinal fractures due to accidental falls veloping countries.22,23 The leading cause of spinal frac- and 13% of the patients were pedestrians who had col- ture in the current study was accidental falls. The com- lision with motor vehicles. These two groups constitute parison between these two major mechanisms of spi- a major portion of the patients who have a high propen- nal injury (i.e. accidental falls and RTCs) illustrates that sity to sustaining extremity injuries.9,21,25,29 Car occu- younger people mostly sustain spinal fractures due to pants develop less extremity injuries due to the pro- RTCs in comparison with accidental fall injuries which tective nature of the car cage against direct injuries to are more common among the aged. Previous studies extremities.22 Head injuries are considerably more com- comparing various subgroups of RTCs have reported mon in the RTC group than the fall group which is due . 8 . Chinese Journal of Traumatology 2010; 13(1):3-9 to several reasons. It was shown in previous studies of the national trauma project that mainly focuses on that pedestrians are prone to head injuries due to double epidemiologic aspects of all types of traumas. Although impact traumas.30,31 Also more than 96% of motorcy- we believe that providing further information on anatomic clists in our study did not wear safety helmets which distribution of spinal fractures including fractures of served to protect the head and neck from serious inju- anterior, central and posterior column spine and diag- ries following an accident32 and more than 93% of car nosis and prognosis significance of Denis classifica- occupants did not use safety belts which predisposes tion in spinal fracture would be useful, mentioned data the passengers to collision with the front windshield are not available. Similarly, we have no accurate data following deceleration injuries and therefore a higher rate on special treatment and outcomes of the patients. of head injuries.33 In conclusion, among injuries to all major organ The mean ISS was relatively low in this study which systems, spine injuries have a poor functional outcome indicates that the severity of injuries in the present study and a high degree of associated morbidity and mortality. is relatively low. This finding is supported by the mean The young population is more prone to spinal injury duration of hospital stay of 4 days in our patients. A after a traumatic injury. This group constitutes the pro- possible explanation might be exclusion of patients who ductive labor force of the country. Among all mecha- were admitted for less than 24 hours. Those who were nisms of spinal fracture, the two that stand out are falls admitted for less than 24 hours either died because of and RTCs. Accidental falls constitute the most com- severity of injuries or were referred to other medical cen- mon mechanism of injury in this study although it is ters due to sustaining a multitude of injuries or ones not significantly different from the frequency of RTCs. which mandated specialized care. The mean ISS was RTCs tend to affect a younger population and are asso- higher in motor vehicle accident injuries compared with ciated with a higher degree of associated injuries and accidental falls. This is in concordance with previous mortality. Therefore devising preventive strategies to studies and is mostly due to the nature of these reduce the number and severity of RTCs deems essen- traumas.21 Spinal fractures due to RTCs are usually of tial to the welfare of a developing country which uses high energy and are more likely to be associated with passenger cars as a major mode of transportation. severe injuries of other body organs, while most spinal Some recommendations to achieve this goal are the fractures due to accidental falls are due to simple falls extension of modern means of public transportation, and falls of less than 4 m height. passing strict regulations regarding the use of safety measures and equipping vehicles with required safety The mean length of hospital stay was not different facilities by manufacturers. between falling and RTCs; however, we found that pa- tients who fell from a height of more than 4 m had a REFERENCES significantly longer duration of hospital stay. 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