The cervical spine alignment is continuous with the thoracic spine, and a trend of the relationship between cervical spine and thoracic spinal alignment was shown in this study. Simulation results suggested that variations in thoracic spinal alignment had a potential impact on cervical spine motion as well as cervical spinal alignment in rear end impact condition.

No abstract

The purpose of this study is to provide the alignment of whole spine in an automotive seated posture by analyzing image data acquired with an upright open MRI system. Five female and three male asymptomatic subjects were scanned in seated and supine postures, and midsagittal images were analyzed in the location of the center of vertebral body and the vertebral angle relative to lower adjacent vertebra from C2 to sacrum. Results showed that 1) females were more likely to have non-lordosis than males, 2) lumbar lordosis was larger for females than males, and sacrum slope was greater for males than females, 3) thoracic kyphosis and T1 slope were greater for the cervical lordotic type than kyphotic type in seated posture.

Experimental studies have demonstrated a relationship between spinal injury severity and vertebral kinematics, influenced by the initial spinal alignment of automotive occupants. Spinal alignment has been considered one of the possible causes of gender differences in the risk of sustaining spinal injuries. To predict vertebral kinematics and investigate spinal injury mechanisms, including gender-related mechanisms, under different seat back inclinations, it is needed to investigate the effect of the seat back inclination on initial spinal alignment in automotive seating postures for both men and women. The purpose of this study was to investigate the effect of the seat back inclination on spinal alignments, comparing spinal alignments of automotive seating postures in the 20° and 25° seat back angle and standing and supine postures. The spinal columns of 11 female and 12 male volunteers in automotive seating, standing, and supine postures were scanned in an upright open magnetic resonance imaging system. Patterns of their spinal alignments were analyzed using Multidimensional Scaling presented in a distribution map. Spinal segmental angles (cervical curvature, T1 slope, total thoracic kyphosis, upper thoracic kyphosis, lower thoracic kyphosis, lumbar lordosis, and sacral slope) were also measured using the imaging data. In the maximum individual variances in spinal alignment, a relationship between the cervical and thoracic spinal alignment was found in multidimensional scaling analyses. Subjects with a more lordotic cervical spine had a pronounced kyphotic thoracic spine, whereas subjects with a straighter to kyphotic cervical spine had a less kyphotic thoracic spine. When categorizing spinal alignments into two groups based on the spinal segmental angle of cervical curvature, spinal alignments with a lordotic cervical spine showed significantly greater absolute average values of T1 slope, total thoracic kyphosis, and lower thoracic kyphosis for both the 20° and 25° seat back angles. For automotive seating postures, the gender difference in spinal alignment was almost straight cervical and less-kyphotic thoracic spine for the female subjects and lordotic cervical and more pronounced kyphotic thoracic spine for the male subjects. The most prominent influence of seatback inclination appeared in Total thoracic kyphosis, with increased angles for 25° seat back, 8.0° greater in spinal alignments with a lordotic cervical spine, 3.2° greater in spinal alignments with a kyphotic cervical spine. The difference in total thoracic kyphosis between the two seatback angles and between the seating posture with the 20° seat back angle and the standing posture was greater for spinal alignments with a lordotic cervical spine than for spinal alignments with a kyphotic cervical spine. The female subjects in this study had a tendency toward the kyphotic cervical spine. Some of the differences between average gender-specific spinal alignments may be explained by the findings observed in the differences between spinal alignments with a lordotic and kyphotic cervical spine.

This study aimed to investigate whether watching an educational video on infant crying and the dangers of shaking and smothering within 1 week after delivery at maternity wards reduces self-reported shaking and smothering, at a 1-month health checkup. A cluster randomized controlled trial, stratified by area and hospital function, was employed in 45 obstetrics hospitals/clinics in Osaka Prefecture, Japan. In the intervention group, mothers watched an educational video on infant crying and the dangers of shaking and smothering an infant, within 1 week of age, during hospitalization at maternity wards, without blinding on group allocation. Control group received usual care. A total of 4722 (N = 2350 and 2372 for intervention and control group, respectively) mothers who delivered their babies (still birth and gestational age < 22 weeks were excluded) between October 1, 2014, and January 31 were recruited. Outcomes were self-reported shaking and smothering behaviors, knowledge on infant crying and shaking, and behaviors to cope with infant crying, assessed via a questionnaire at a 1-month health checkup. In all, 2718 (N = 1078 and 1640) responded to the questionnaire (response rate: 58.3%), and analytic sample size was 2655 (N = 1058 and 1597 for intervention and control group, respectively). Multilevel analysis was used to adjust for correlation within the cluster. Prevalence of shaking was significantly lower in the intervention group (0.19%) than in the control group (1.69%). Intention-to-treat analysis showed an 89% reduction in the reported prevalence of self-reported shaking (OR: 0.11, 95% CI: 0.02–0.53) due to watching the educational video. However, self-reported smothering behavior showed no significant reduction (OR: 0.66, 95% CI: 0.27–1.60). No side effects were reported. Watching an educational video on infant crying and the dangers of shaking and smothering within 1 week after delivery at maternity wards reduced self-reported shaking at 1 month of age. UMIN Clinical Trial Registry UMIN000015558.