Age-related and specific characteristics of severely injured MVPs need to be individually addressed in the trauma management. Especially within the first 5 years of age, children are most likely exposed to road traffic accidents as MVPs [2,3,4, 7, 14, 16, 17, 27]. The discussion about safety regulations for child passengers, such as re-boarding has not been finally resolved for children older than 15 months of age [1, 6, 8, 10]. Not only the seating position but also the point of accident impact is essential in the development of injury pattern [4, 8, 10, 17]. A combination of age-related specific anatomical and physiological parameters as well as the accident impact and the safety features of the car are only some of the multiple influencing factors. The misuse quote of child restraint system (CRS) is high for infant carrier (group 0 + seat) as well as for child seats with integrated harness or shield system (group 1 CRS) [15]. In these seats, children are fastened with a harness system, additionally the seat is secured with the seat belt in the car. Depending on the respective system, this combination offers a great potential of misuse. Systems that simplify this process, like ISOFIX, have a significant potential to reduce the share of misuse.
The data from the TR-DGU showed, that the diagnostic management of severely injured MVPs seems to differ from the management of adult patients. The early injury assessment of abdominal and thoracic injuries is analog to the S3 guideline [19] performed using eFAST and followed by a whole-body CT scan. The evidence for early injury assessment by whole-body CT scan of severely injured adult patients shows a significantly lower mortality rate [9, 19]. In the underlying data of severely injured children, CT scans were performed in only 74.3–80.9% of the cases before admission to the ICU, while plain film X-ray was used in 27.6% of the cases in the TRU. More than half of the severely injured MVPs though were diagnosed analog to guidelines of Advanced Trauma Life Support (ATLS) in the TRU using the combination of eFAST and CT-scan (51.1%) [2]. If no CT scan was used (21.3%), almost all of the patients had already received an eFAST or X-ray. Although this management differs from the general algorithm of adults, it seems to be safe enough in the combination of admission to ICU. Since the included MVPs suffer at least from an AIS-2 + -injury, they might have received further diagnostic after admission to ICU. The use of MRI within the early trauma management should be discussed further, especially if the children are in hemodynamically stable condition. An injury classified as AIS 2 + at a minimum, is difficult to diagnose completely without CT-scan or MRI. In addition, other severe injuries might be missed. The complete pattern of injury should be thoroughly assessed within the early trauma management in the TRU independently from age [9, 19, 21, 22].
The youngest children are at the highest risk of head (incl. TBI) and spine injury, while severe facial injury and severe abdominal injury show an opposite tendency. Especially severe injuries to the head and cervical spine need early intention. Although re-boarded, the youngest age group shows the highest mortality rate of 15.8%, the highest proportion of AIS-6-Injuries (7.9%) and the significant highest proportion of unconsciousness (31.6%). Thus, the seating position itself does not seem to be enough to protect this age group in case of an accident [4, 5, 12, 25, 27]. At the same time, the proportion of spine injuries to the cervical spine was very high in the front-faced age groups (2–3-year-old group 75.0% and 4–5-year-old group 70.0%, respectively), the re-boarded seating position especially in the 0–1-year-old group seems to be favorable in this specific matter. Yet the fact of significant higher number of severe injuries to the spine especially in the mostly forward-faced 2–3-year-old group, as well as the overall severity of injury in the 0–1-year-old group in combination with the high frequency of CPR, positions the youngest age groups being at the highest risk. Not only are the anatomical condition of the children and the technical mechanism of accident important factors influencing the pattern of injury. Mitchell et al. 2015 were able to show, that in 2412 MVPs, unauthorized vehicle drivers had twice the odds (OR: 2.21, 95% CI 1.47–3.34) and learner/provisional drivers had one-and-a-half times higher odds (OR: 1.54, 95% CI 1.15–2.07) of a child car occupant sustaining a serious injury compared to a minor injury [14]. Although older children suffer from severe abdominal injury significantly more often, their rate of AIS-6-Injuries, spine injuries and injuries to the extremities are lower. The children in the age of 2–3-year-old group show the highest frequency of severe lower limb injury. This might be a combination of misuse of car seats, incorrect use of restraining systems and the so-called “submarining effect”, which is caused by a sliding of the body below the belt, acting like a hinge and causing the seatbelt syndrome with severe abdominal and/or spinal injury [5, 12, 24, 25]. The rear seats are safer than the front seats and the center rear seat is safer than the outside positions [6, 8, 10], but a lap belt alone should be avoided. It is common for children to suffer hand, foot, and wrist fractures when bracing for the impact of a car crash [1]. Seat belts could also cause fractures of the pelvis and severe abdominal as well as thoracic injuries. In the event that a child is thrown from the vehicle, femur and arm fractures are common. But the rotational aspect of a collision or a side collision seems also to have an impact on the pattern of injury [6, 8, 10].
The mortality rate of young child MVPs is with 15.8% compared to older children or adults very high. Although the youngest children are at highest risk, their survival rate after CPR is the highest (7 out of 8). This discrepancy shows the high vulnerability due to anatomical and physiological condition of the youngest child MVPs in accidents and their hemo-dynamical recompensation potency at the same time. Naidoo et al. 2015 observe a similar high mortality rate in primarily treated road traffic victims (15.4%) in their child collective with 21% injured as MVPs and a median ISS of 25 points [16]. The main reason for death in their collective was TBI (88.4%), severe injury to the extremities (38.5%) and abdomen as well as thoracic wall (34.6%) [16]. This underlines the overall exposition of the head, cervical spine, thorax/abdomen and extremities even if re-boarded. That re-boarding is important for survival as shown by multiple studies [3, 4, 11, 12, 17]. But the reconstruction of the accidents themselves throughout the literature proof, that the seating position itself is not the only prognosis influencing measure, since point of impact, vehicle construction, age, grade of deceleration, drivers experience and behavior are also accountable measurements.
Besides the medical data about this special group of patients, accident-related technical information is needed to develop more prevention activity. Müller et al. 2018 were able to show, that children are correctly restrained in the first 15 months in 46% [15]. Since the underlying data of the present study show, that the age group of 0–1 years is the most exposed age group to severe injury as MVPs in accidents, but mostly correctly restraint and even re-boarded positioned, the security systems do not seem to address the potential pattern of injury and the different ways of accident impact. The significant higher amount of severe abdominal injury in the oldest age group seems to be mainly caused by the car seat restraints themselves [12]. The cause and specific pattern of abdominal injury need to be assessed more specific in future research projects to differentiate between misuse and construction deficits. The often-used lap belt in the center rear position in combination with a discrepancy in seat depth to lower extremity length seems to be common problem in severe abdominal injuries, injuries to the lumbar spine and “submarining effect” [5, 12, 24, 25]. Nevertheless, the correct positioning and restraining of children in motor vehicles seem to be the most important prevention. Lapner et al. 2001 were able to show, that proper seat belt restraint reduces the morbidity in children involved in motor vehicle accidents as MVPs, supporting the key message of the underlying data of this study. For older children, three-point pediatric seat belts should be improved to reduce morbidity and mortality [4, 12, 25].
Limitations
To presume seating positions of children in motor vehicles, the data of the TR-DGU needed to be supplemented by other publications of accident data. According to Müller et al. 2017, it is feasible to presume the seating positions in the 0–1-year-old and 4–5-year-old groups, although especially the correct use of restraining systems might be incorrect in the older age groups of children [15]. The data of the TR-DGU though do not provide information about the seating position and even if the percentage of children who are seated in a re-boarding position in the ages of 0–1 years is almost 100%, there might still be a minimal percentage of children who are positioned incorrectly even in that age group.
Due to the fact, that the data inclusion criteria to the TR-DGU only address children who got admitted to the trauma center, we do not have enough information about the children, who died during the pre-hospital trauma management, though this number seems to be quite low, according the Destatis-report 2021 [7].
The difference in diagnostic management between children and adult multiple trauma patients can only be interpreted carefully, due to the fact, that CT or MRI scans which were performed after admission to the ICU are not documented. The documentation of MRI scans as part of the early trauma management was not part of the TR-DGU before the year 2015.
The focus of this study is the evaluation of severely injured children. We did not investigate children with minor or no injury as MVP. Thus, the presented data cannot provide information about the efficiency of child safety systems in general. The fact that severe injury in the presented age groups is seldom might be an effect of a general high quality of safety systems, if applied correctly.