Study Design. Retrospective study. Objective. To describe the epidemiology and clinical outcomes of pediatric patients with spinal cord injury (SCI) without radiographic abnormality (SCIWORA) in mainland China for the first time. Summary of Background Data. SCIWORA is a syndrome that often occurs in children mainly due to the unique biomechanics of the pediatric spine. Although there have been numerous retrospective studies on pediatric SCIWORA, and mainland China has more patients with SCI than anywhere else, pediatric patients with SCIWORA in mainland China has not been described in any study. Methods. Review of all cases with SCIWORA at Beijing Children's Hospital between July 2007 and December 2019. Results. Of the 189 pediatric patients with SCI 140 had SCIWORA (age: 5.65 AE 2.60 years, male-to-female ratio: 2:5). Main causes of injuries were sports (41%, mostly backbend), falls (27%), traffic accidents (10%), and violence (8%). Lesions were located at the thoracic (77%), cervical (10%), multiple (5%), and lumbar (4%) levels. Incubation period was 2 AE 6 hours.hours. Pathological characteristics of SCI were detected in 96% patients by magnetic resonance imaging (MRI). Based on the American Spinal Injury Association impairment scale (AIS), many patients had complete impairment (50% AIS A, 45% AIS B/C/D, 1% AIS E). Particularly, the five patients with normal MRI tended to have mild injury (AIS D) (P < 0.001), but they still showed abnormal reflex. In the one patient who could not be graded at all by AIS, his only functional deficits were abnormal upper and lower limb muscle tones. A total of 59% patients were treated with methylprednisolone, dexamethasone, or both. Out of 76 patients 59 showed neurological improvement before discharge. The only association among age, cause of injury, level of lesion, incubation period, AIS grade, type of corticosteroid therapy, and neurological improvement was between level of lesion and AIS grade (P < 0.001). Conclusion. Demographic and clinical differences exist in patients with SCIWORA. MRI and detailed neurological examinations should both be performed for proper diagnosis. There is still a need to develop better treatment strategy for these patients.

Women with abdominal aortic aneurysm (AAA) have a higher incidence of complications after Endovascular aneurysm repair (EVAR), most of which are related to the migration of stent‐graft. The different force acting on the stent‐graft after EVAR caused by different abdominal artery anatomy of male and female AAA patients may be the reason for the sex‐different complications. This article aims to explore the possible biomechanical mechanisms of sex differences by making a comparison of displacement force acting on the stent graft of male and female AAA patients. To explore the effect of different vascular anatomy on stent‐graft migration, the uniformed models were constructed according to the specific vascular anatomy parameters of AAA patients of different sex, which have been measured before. The computational fluid dynamics method was used to quantitate the pulsatile force acting on the stent‐graft after EVAR in a cardiac cycle. Then the displacement force was calculated with the pressure and the wall shear stress, and the total and area‐weighted average of displacement force acting on the stent‐graft were compared respectively. In one cardiac cycle, the wall pressure for the male model is greater than that of the female model (2.7–4.4 vs. 2.2–3.4 N), and the wall shear force for the female model is slightly greater (0–0.0065 vs. 0–0.0055 N). The displacement force is mainly provided by the wall pressure, which is also greater in the male model. However, the area‐averaged displacement force is greater for the female model than that for the male model (180–290 vs. 160–250 Pa). Because of the different vascular anatomies, the impact caused by the pulsating aortic blood flow on the AAA stent‐graft of women after EVAR was greater than that of men. Women's vascular anatomy leads to greater area‐averaged displacement force after stent‐graft implantation, resulting in a greater risk of stent‐graft migration, which might be one of the reasons why women had a higher incidence of complications after EVAR.