BACKGROUND:The authors found that when the bilateral percutaneous vertebral augmentation is used to treat osteoporotic vertebral compression fractures with a total bone cement injection of 4 mL or more,different distribution patterns were usually presented on the X-rays;however,there were few reports addressing the effects of these patterns of bone cement distribution on the biomechanical properties of fractural vertebrae. OBJECTIVE:To further explore the biomechanical effects of different bone cement filling doses and distribution patterns on biomechanics of the fractural vertebrae using the finite element method. METHODS:The L1-L3 finite element models of osteoporosis were established,and the vertebral compression fractures were simulated in L2.Four distribution patterns bilateral partial fusion(FH type),full fusion(FO type),symmetrical separation(SA type),and asymmetric segregation(SN type)were simulated in 4 and 6 mL injections in the osteoporotic vertebral compression fracture models,respectively,and a total of nine sets of models were obtained.These models were solved under the same boundary conditions and compared with the stress and displacement of the L2 fractural vertebra. RESULTS AND CONCLUSION:(1)The maximum stresses of the nine groups of models were concentrated in the L2 fractural area,and the maximum stress and maximum displacement of each filling model were lower than in the osteoporotic vertebral compression fracture model,indicating the effectiveness of bone cement filling in the treatment of osteoporotic vertebral compression fracture.(2)Compared with 4 mL bone cement filling,6 mL bone cement filling could significantly reduce the stress of fractured vertebrae and enhance the strength of fractured vertebrae while improving the stability of fractured vertebrae.(3)In the same state of movement,the FH type stress was the least,followed by the SA type,both of which were close.FO type stress was the largest,especially in the lateral bend,which might be associated with its cluster shape resulting in the concentration of lateral stress.In the aspect of displacement,FH type was the least and FO type was the largest.(4)The results show that increased dose of bone cement injection reduces fractural vertebral stress and improves stability,but increases the risk of leakage.Bilateral symmetrical dispersed bone cement(FH type,SA type)is superior in restoring vertebral strength and stability than full fusion(FO type),asymmetric separated(SN type)bone cement.Therefore,when clinically performing bilateral percutaneous vertebral augmentation treatment of osteoporotic vertebral compression fractures,the bilateral symmetric dispersions of the distribution are first guaranteed;priority is recommended for FH type distribution,for appropriate stress stimulation and best stability.

Objective To observe the changes of renal tubular injury and the extent of interstitial fibrosis in the C57BL/6 mouse models of chronic kidney disease(CKD),and provide experimental animal evidence for study of the pro-gression of acute kidney injury(AKI)to chronic kidney disease as well as its mechanisms. Methods Twenty-four 8-week-old male C57BL/6 mice were randomly and equally divided into control group, low-dose, medium-dose, and high-dose cisplatin groups,6 mice in each group. Mice in the cisplatin groups were administrated with 5,7 or 10 mg/kg cispla-tin by intraperitoneal injection once a week for 4 weeks. Plasma creatinine and 24-hour urinary protein were detected to as-sess the renal function. The mice were sacrificed, and plasma and kidney samples were collected for subsequent tests. Pathological changes were observed using periodic acid-Schiff(PAS)staining. To evaluate renal tubules injury, the ex-pression of kidney injury molecule 1(KIM-1)was examined by immunohistochemistry and the level of urinary N-Acetyl-β-D-glucosaminidase was detected with a commercial kit. The infiltration of CD3-positive T cells and F4/80-positive macro-phages was observed by immunohistochemistry(IHC)and immunofluorescence. The expression of collagen I and α-smooth muscle actin(α-SMA)were tested by immunohistochemistry to assess the renal fibrosis, while total kidney collagen was detected by Picrosirius red staining. Results In contrast to the normal control group,the kidney injury became more seri-ous in the cisplatin-treated mice as cisplatin concentration increased. Particularly,significant kidney damage was observed in the high-dose cisplatin group. Compared with the control group,the plasma creatinine and 24-hour urinary protein were significantly increased in the high-dose cisplatin group(P<0.05 and P<0.001)indicating impaired renal function. Mor-phologically,numerous clear vacuoles and necrosis were present in renal tubule epithelial cells in the high-dose cisplatin group. The expression of KIM-1 was markedly up-regulated and the level of urinary NAG was elevated. Infiltration of CD3-positive T cells and F4/80-positive macrophages was enhanced in the mice of high-dose cisplatin group. Data from immuno-histochemistry and picrosirius red staining showed that mice of the high-dose cisplatin group developed renal fibrosis evi-denced by markedly up-regulated expression of collagen I and α-SMA. Conclusions Repeated administration of 10 mg /kg cisplatin for 4 weeks can induce chronic renal insufficiency in mice,which may serve as a novel model for the research on underlying mechanisms of progression from acute kidney injury to chronic kidney disease.

During coronavirus disease 2019 epidemic, the treatment of severe trauma has been impacted. The Consensus on emergency surgery and infection prevention and control for severe trauma patients with 2019 novel corona virus pneumonia was published online on February 12, 2020, providing a strong guidance for the emergency treatment of severe trauma and the self-protection of medical staffs in the early stage of the epidemic. With the Joint Prevention and Control Mechanism of the State Council renaming "novel coronavirus pneumonia" to "novel coronavirus infection" and the infection being managed with measures against class B infectious diseases since January 8, 2023, the consensus published in 2020 is no longer applicable to the emergency treatment of severe trauma in the new stage of epidemic prevention and control. In this context, led by the Chinese Traumatology Association, Chinese Trauma Surgeon Association, Trauma Medicine Branch of Chinese International Exchange and Promotive Association for Medical and Health Care, and Editorial Board of Chinese Journal of Traumatology, the Chinese expert consensus on emergency surgery for severe trauma and infection prevention during coronavirus disease 2019 epidemic ( version 2023) is formulated to ensure the effectiveness and safety in the treatment of severe trauma in the new stage. Based on the policy of the Joint Prevention and Control Mechanism of the State Council and by using evidence-based medical evidence as well as Delphi expert consultation and voting, 16 recommendations are put forward from the four aspects of the related definitions, infection prevention, preoperative assessment and preparation, emergency operation and postoperative management, hoping to provide a reference for severe trauma care in the new stage of the epidemic prevention and control.