The between-country differences in SCI etiology, affected spinal level, and response to care seen in this study, as well as when comparing this study’s findings to published global statistics, warrant discussion, in part because they imply sociocultural features of SCIs in the studied countries which characterize broader global health and occupational disparities[2].
Etiology
The likeliest cause of SCIs in Malaysia and Thailand was transport, whereas the likeliest cause in the four remaining countries was falls, three quarters of which were from a height of one meter or more. These data correlate with older published findings which generally identify transport as the leading cause of traumatic SCIs in high income countries (HICs) and high falls as the leading cause in LMICs[8]. This etiological split along GDP lines may be a product of the number of vehicles per capita in these countries: the higher the number, the greater the likelihood of crashes. Of the countries included in this study, Malaysia boasts the highest numbers of vehicles per capita, at 542 per 1,000[9]. On the opposite end of the spectrum, Nepal—a country where transport accounted for only 22% of all SCIs—reports 113 vehicles per 1,000[10].
Recent epidemiological data indicate a shift in SCI etiology in HICs with aging populations, such as Finland[11], Japan[12], South Korea[13], and the United States and Canada[14], from transport to low falls as the leading cause. This may be related both to shifting demographics and improved motor vehicle safety features in HICs.
This recent phenomenon remains contrasted with this study’s finding that the majority of falls occurred from heights of one meter or greater. This contrast is likely related to sociocultural features of SCI etiology in the studied countries which are important to understand since SCI etiology was a predictor of SCI severity in this study. This relationship is likely influenced by the correlation between high falls and damage caused by broad kinetic energy transfer gradients.
India
Nearly half (n = 503) of all SCIs in India in this study resulted from falls, of which 65% (n = 327) occurred from a height of one meter or greater. A 2012 study conducted at the Indian Spinal Injuries Centre (ISIC) found that 85% (n = 128) of all falls which resulted in SCI occurred from a height of one meter or greater, and specifically that 22% of high falls occurred from a rooftop, 17% from a balcony, and 12% from a tree[15]. Data from rural India published in 1986 indicated that 55% (n = 120) of all SCIs were the result of falling from trees[16]. It has been suggested that many of such falls are related to jobs[15], such as construction or maintenance, and farming tree nuts[17]. Falls from rooftops can also occur as a result of people seeking cooler temperatures on hot days by lying on the roof, many of which do not have rail guards[8]. Such instances may contribute to the 20% of all falls in the ISIC study which were associated with an infrastructural factor[15].
Nepal
Sixty-two percent (n = 634) of all SCIs in Nepal in this study resulted from falls. This finding correlates with results from a recent systematic literature review of SCIs in Nepal which showed falls as the cause of 60% (n = 1077) of traumatic SCIs[18]. In this study 94% (n = 596) of falls in Nepal occurred from a height of one meter or greater. The most common surfaces from which high falls in Nepal occur are ladders and roofs, cliffs, and trees[18]. As in India, a great number of these types of high falls are job-related, including falls from trees in the process of gathering fodder for cattle[18].
Bangladesh
Over half (n = 165) of all SCIs in Bangladesh in this study resulted from falls, of which nearly 70% (n = 113) occurred from a height of one meter or greater. High falls in Bangladesh are also understood frequently to be job-related; researches at the Centre for the Rehabilitation of the Paralysed in Dhaka isolated trees and high-rise buildings as surfaces from which workers who sustain SCI commonly fall[19]. These researchers also found an association between SCI and socioeconomic status (SES), reporting that workers with a low SES often work at dangerous heights with limited safety equipment (e.g., rails and harnesses), placing them at higher risk of SCI caused by high falls[19].
Sri Lanka
Nearly 63% (n = 10) of all SCIs in Sri Lanka in this study resulted from falls, of which three occurred from a height of one meter or greater, five occurred at the same level, and two were from unspecified heights. Published SCI data in Sri Lanka are sparse, but one study conducted at the Rheumatology and Rehabilitation Hospital in Ragama documented that nearly half of all traumatic SCIs were caused by work-related falls, and an additional nearly 23% were caused by falls at home or during recreational activities[20].
Spinal Level
In contrast with most other published epidemiological studies of global SCIs where the cervical spine is the most commonly injured region[8], the thoracic spine in this study was most commonly injured, with nearly half (n = 977) of all SCIs occurring there. This finding is meaningful because thoracic SCIs are known to be associated with both a higher likelihood of a neurologically complete injury and lower recovery rates, as compared to SCIs of other single and multiple regions[21], due in part to the smaller diameter of the spinal canal in the middle thoracic spine. Accordingly, in this study three of every four (n = 757) thoracic SCIs resulted in AIS A, compared to half (n = 444) of cervical, a quarter (n = 59) of lumbar, a third (n = 4) of sacral, and less than half (n = 157) of multiple spinal region SCIs (p < 0.001). Additionally, there was a significantly lower likelihood that thoracic AIS grades improved in hospital, as compared to cervical (OR = 1.65), lumbar (OR = 2.24), and multiple spinal (1.79) regions (p = 0.010).
The high prevalence of thoracic SCIs in the six countries included in this study may be another example of global health disparities. High energy impact is necessary to cause traumatic SCI in the thoracic region, since the ribcage provides this region with greater structural stability and energy absorption. In this study 40% (n = 522) of falls and 37% (n = 304) of transport SCIs affected the thoracic region. The lack of readily accessible safety equipment such as harnesses, scaffolding, seatbelts, and airbags[22] in the countries included in this study may contribute to the energy transfer gradient breadth and therefore to injury severity and poorer prognosis in these countries.
Response to Care
The likelihood of SCI inpatient improvement in this study was highest in Thailand (OR = 4.23), as compared to India (p < 0.001). While these results may be related to a higher proportion of incomplete injuries on presentation in Thailand[22] (only 30%, n = 37, of SCI presentations were AIS A in Thailand, as compared to 58%, n = 598, in India; p < 0.001), or simply between-country nonuniformity in AIS grading[8], socioeconomic factors may also contribute. Specifically, given evidence that prehospital care and early surgical management of traumatic SCI influence neurologic recovery[22, 23], this finding may also be related to Thailand’s burgeoning emergency medical services (EMS) infrastructure which has recently improved through public policy measures[24]. Currently, Bangkok boasts an EMS survival-to-admission rate which surpasses Tokyo’s (27.7% and 27.3%, respectively)[25], as well as call-to-arrival times which are trending downward[26]. Bangladesh, which also showed a higher likelihood of inpatient improvement (OR = 3.60) than India (p < 0.001) in this study, is also taking emergency response optimization measures[27].
Unfortunately, LMICs generally lack robust EMS systems. This lack likely undergirds the estimated 90% of all global trauma-related deaths which occur in LMICs, as 80% occur in the prehospital setting[28], and illuminates another instance of global health disparity.
Limitations
The ages of nearly half (n = 1177) of people in this study with SCI are unreported, which influences the descriptive and regression analyses and may inaccurately report the effects of age on SCI severity and response to care. However, our finding that a higher percentage of younger individuals suffered severer injuries than elderly individuals is generally consistent with previously published data[29]. Additionally, call-to-arrival and arrival-to-surgery times are unknown. Such data could provide a helpful insight into this study’s inpatient improvement results.
Next Steps
The above results can be used to inform future SCI research in Eastern and South-eastern Asian LMICs. For instance, future epidemiologic studies can build on these findings to understand with greater clarity the roles of EMS systems and timeliness of surgical intervention in response to care. Additionally, future prospective studies can engage community members to develop methods of limiting energy transfer in high-risk settings by addressing both sociocultural and mechanical factors related to traumatic SCI. Some such community-based interventions have already been developed and implemented, though not rigorously studied, such as the “tree scooter”[17]. It is hoped that as country-specific factors related to this significant health problem are better understood, better country-specific, community-engaged interventions will result in improvements in both SCI severity and response to care.