When walking is bad for your back: a cohort study of risk factors for traumatic spinal injury in Abuja

Introduction This study evaluates characteristics and risk factors of traumatic spinal injuries (TSIs) treated at a trauma center in Abuja, Nigeria. TSIs are a global concern. They are frequently disabling, leading to economic, workforce, and quality of life strain. Little is known of the epidemiology of TSIs in Nigeria. Methods Data were collected from National Hospital Abuja's trauma registry on 3025 patients treated at the hospital between 2014 and 2017. Patient characteristics were compared between spinal and nonspinal injury groups. Multiple logistic regression was used to identify risk factors of TSIs. Results 15% (452) of all injuries were spinal. Road traffic crashes were a significantly greater cause of spinal (77.4%) than nonspinal (59.4%) injuries (p<0.0001). Pedestrians were involved in 19% (356) of total crashes, occupying a significantly larger proportion of spinal (18.6%) than nonspinal (10.6%) injuries (p<0.0001). Three variables were modeled as risk factors of crash-related TSIs: mode of transportation, age, and gender. Only mode of transportation demonstrated statistical significance, with involvement as a pedestrian showing an adjusted odds ratio of 1.38 (95% confidence interval: 1.03-1.85, p=0.0329). Conclusion Determining characteristics and risk factors of TSIs is an essential step in addressing this health concern in Nigeria. Crashes are a significant cause of TSIs, and a quarter of TSI patients involved in a crash are pedestrians. Involvement in a crash as a pedestrian is associated with high risk of TSI. These results can help guide both the development of spinal injury prevention policies and the allocation of resources.


Introduction
Traumatic spinal injuries (TSIs) are a global public health concern [1].
TSIs include a variety of injuries which can affect the spinal cord, nerve roots, osseous structures, and/or soft tissues surrounding the spinal column [1,2], and are caused by acute trauma to the neck or back [3]. There is a dearth of global TSI data [2], though some traumatic spinal cord injury (TSCI) data have been published.
Between 250,000 and 500,000 people globally suffer a spinal cord injury each year [4]. Spinal injuries are particularly concerning in lowand middle-income countries (LMICs) [2], where incidence rates of TSCI can reach 29.7 per million people, compared to 13.1 per million in high-income countries [5]. Most TSIs globally are road traffic crashrelated [2,[6][7][8][9][10][11], though falls are the leading cause of TSCIs in Turkey [12] and are becoming a larger cause of TSIs in both the United States [13] and Canada [14]. In Nigeria occupational hazard has also been implicated as a significant cause of TSIs [15]. Crashes are rapidly becoming one of the leading causes of injury and death worldwide. They are predicted to become the seventh leading cause of death globally by 2030 [16], and will also in part due to related TSIs become the fourth leading cause of disability-adjusted life year (DALY) loss by that year [17]. Nigeria, in particular, is acutely affected by road traffic crashes. The crash-related mortality rate in 2012 was 162 per 100,000 in Nigeria, which is 636% higher than the global average of 22 per 100,000 [18]. A Nigerian has one chance in nine of dying due to a crash, and one chance in three of being injured due to one in his/her lifetime [19]. Up to 4 million Nigerians are injured in crashes annually [20]. In addition, crashes are the leading cause of death in the world for those aged 15 to 29 years [16]. This is of particular concern in countries like Nigeria which suffer from skilled workforce depletion [21], as the economic productivity potential of this age group is high [22].
Mortality from TSIs is concerning; however the disability rate and long-term consequences are severe [2,14,[23][24][25]. Just fewer than 18% of TSCIs were associated with mortality in one study of trauma patients over a 15-year period in Lagos, Nigeria [10]. A much greater percentage-nearly half of patients involved in TSIs-may experience chronic disabling symptomatology [26,27]. Furthermore, pain-related disability is more common following trauma to the spine than to other body parts [28]. TSIs can therefore lead to extensive medical treatment, financial and workforce strain [11,14], and loss of quality of life for the TSI patient [9,25]. Little is known of the epidemiology of TSIs globally, and especially in Nigeria, [29] though reports suggest a consistent rise in cases [10]. The study presented here provides novel information on characteristics and risk factors of TSIs in Abuja, Nigeria. It was hypothesized that involvement in a road traffic crash as a pedestrian is a risk factor of TSI. This study's results will inform the "urgent need to improve the quantity and quality of [spinal injury] data collection" [4] and facilitate and guide efforts toward prevention and treatment of TSIs in Nigeria [9]. Patient population: patients included in this analysis were categorized into spinal injury and nonspinal injury groups based on information gathered from the registry. Also, since cervical spine injuries accompany severe craniocerebral injuries caused by road traffic crashes [31][32][33], crash patients who scored 3 to 8 on the injury patients. Of a total of 3025 patients, 452 (14.9%) were determined to be spinal injury patients. These were classified by injury mechanism (road traffic crash, assault, burn, and fall), injury type (cord/neurological, head, fracture, penetration, and soft-tissue), and affected spinal level (cervical, thoracic, and lumbar/sacral). Of 1879 total road traffic injuries, 350 (18.6%) were determined to be spinal. Road traffic crashes were subclassified by mode of transportation: pedestrian; motorcycle, tricycle, or bicycle; or vehicle with four or more wheels.

Results
A total of 3025 trauma patients treated at the National Hospital Abuja between September 2014 and February 2017 were included in the analysis. Table 1 summarizes descriptive statistics of patient demographics and injuries. The median patient age was 30 years (interquartile range, IQR: 22 to 38); ages ranged from 0 to 92 years.
Most patients were male (75.9%, n=2289), and the majority of patients were injured in a road traffic crash (60.4%, n=1879).
Patient discharge status and information on mortality were incomplete in 26% (798) of cases, and leaving against medical advice is reported in 9% (267) of general trauma cases, 6% (10) of crash cases, and 3.5% (16)    efforts to avoid formal medical assessment and potential legal citation, which could lead to vehicle confiscation [38,42]. A greater likelihood than reported of TSI for motorcycle, tricycle, or bicycle riders involved in crashes is possible, due to the increased vulnerability both of the rider's head/neck (related to limited helmet use [43][44][45]) and of the back [46].

Conclusion
Determining characteristics and risk factors of TSIs is an essential step in addressing this health concern in Nigeria. TSIs can assert a significant burden on both the individual patient and his/her community and economy. Road traffic crashes are a significant cause of TSIs in Abuja. A quarter of patients seen at National Hospital Abuja whose spines were injured in a crash were pedestrians, and nearly half of children and adolescents who sustained TSI in a crash were pedestrians. This study's findings suggest that a crash patient's status  Tables and figure   Table 1: patient demographic and injury characteristics