Introduction: Venous thromboembolism can be divided into deep vein thrombosis and pulmonary embolism. These diseases are a major factor affecting the clinical prognosis of patients and can lead to the death of these patients. Unfortunately, the literature on the risk factors of venous thromboembolism after surgery for spine metastatic bone lesions are rare, and no predictive model has been established. Methods: We retrospectively analyzed 411 cancer patients who underwent metastatic spinal tumor surgery at our institution between 2009 and 2019. The outcome variable of the current study is venous thromboembolism that occurred within 90 days of surgery. In order to identify the risk factors for venous thromboembolism, a univariate logistic regression analysis was performed first, and then variables significant at the P value less than 0.2 were included in a multivariate logistic regression analysis. Finally, a nomogram model was established using the independent risk factors. Results: In the multivariate logistic regression model, four independent risk factors for venous thromboembolism were further screened out, including preoperative Frankel score (OR=2.68, 95% CI 1.78-4.04, P=0.001), blood transfusion (OR=3.11, 95% CI 1.61-6.02, P=0.041), Charlson comorbidity index (OR=2.01, 95% CI 1.27-3.17, P=0.013; OR=2.29, 95% CI 1.25-4.20, P=0.017), and operative time (OR=1.36, 95% CI 1.14-1.63, P=0.001). On the basis of the four independent influencing factors screened out by multivariate logistic regression model, a nomogram prediction model was established. Both training sample and validation sample showed that the predicted probability of the nomogram had a strong correlation with the actual situation. Conclusion: The prediction model for postoperative VTE developed by our team provides clinicians with a simple method that can be used to calculate the VTE risk of patients at the bedside, and can help clinicians make evidence-based judgments on when to use intervention measures. In clinical practice, the simplicity of this predictive model has great practical value.

Background: Aseptic loosening of distal femoral tumor implants significantly correlates with the resection length. We designed a new “sleeve” that is specially engaged in the metaphysis at least 5 cm proximal to the knee joint line to preserve as much bone stock as possible. This study investigates the influence of a metaphyseal sleeve on the stress-strain state of a bone tumor implant system in the distal femur.Methods: Cortex strains in intact and implanted femurs were predicted with finite element (FE) models. Moreover strains were experimentally measured in a cadaveric femur with and without a sleeve and stem under an axial compressive load of 1000 N. The FE models, which were validated by linear regression, were used to investigate the maximal von Mises stress and the implanted-to-intact (ITI) ratios of strain in the femur with single-legged stance loading under immediate postoperative and osseointegration conditions.Results: Good agreement was noted between the experimental measurements and numerical predictions of the femoral strains (coefficient of determination (R²) ≥ 0.95; root-mean-square error (RMSE%) ≈ 10%). The ITI ratios for the metaphysis were between 13 and 28% and between 10 and 21% under the immediate postoperative and osseointegration conditions, respectively, while the ITI ratios for the posterior and lateral cortices around the tip of the stem were 110% and 119% under the immediate-postoperative condition, respectively, and 114% and 101% under the osseointegration condition, respectively. The maximal von Mises stresses for the implanted femur were 113.8 MPa and 43.41 MPa under the immediate postoperative and osseointegration conditions, which were 284% and 47% higher than those in the intact femur (29.6 MPa), respectively.Conclusions: This study reveals that a metaphyseal sleeve may cause stress shielding relative to the intact femur, especially in the distal metaphysis. Stress concentrations might mainly occur in the posterior cortex around the tip of the stem. However, stress concentrations may not be accompanied by periprosthetic fracture under the single-legged stance condition.

Aim: Pseudouridylation has demonstrated the potential to control the development of numerous malignancies. PUS7(Pseudouridine Synthase 7) is one of the pseudouridine synthases, but the literature on this enzyme is limited to several cancer types. Currently, no investigation has been performed on the systematic pan-cancer analysis concerning PUS7 role in cancer diagnosis and prognosis. Methods: Employing public databases, including The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression Project (GTEx), Human Protein Atlas (HPA), UALCAN and Tumor Immune Single-cell Hub (TISCH), this work investigated the PUS7 carcinogenesis in pan-cancer. Differential expression analysis, prognostic survival analysis and biological function were systematically performed. Furthermore, PUS7 potential as an osteosarcoma biomarker for diagnosis and prognosis was assessed in this study. Results: The findings indicated that PUS7 was overexpressed in the majority of malignancies. High PUS7 expression contributed to the poor prognosis among 11 cancer types, including Adrenocortical Cancer (ACC), Bladder Cancer (BLCA), Liver Cancer (LIHC), Kidney Papillary Cell Carcinoma (KIRP), Mesothelioma (MESO), Lower Grade Glioma (LGG), Kidney Chromophobe (KICH), Sarcoma (SARC), osteosarcoma (OS), Pancreatic Cancer (PAAD), and Thyroid Cancer (THCA). In addition, elevated PUS7 expression was linked to advanced TNM across multiple malignancies, including ACC, BLCA, KIRP, LIHC and PAAD. The function enrichment analysis revealed that PUS7 participates in E2F targets, G2M checkpoint, ribosome biogenesis, and rRNA metabolic process. Moreover, PUS7 is also a reliable biomarker and a potential therapeutic target for osteosarcoma. Conclusions: In summary, PUS7 is a putative pan-cancer biomarker that reliably forecasts cancer patients’ prognosis. In addition, this enzyme regulates the cell cycle, ribosome biogenesis, and rRNA metabolism. Most importantly, PUS7 possibly regulates osteosarcoma initiation and progression.

Objective: Pre‐implantation sterilization procedures for tendons are important measures to reduce the risk of disease transmission, however these procedures may compromise tendon microarchitecture and biomechanical properties to varying degrees. We explore the effects of different sterilization procedures on the micro‐histology, biomechanical strength and biochemical properties of human tendon allografts in vitro study.Methods: The tendon allografts were harvested from cadaveric donors after the donors were serologically screened by antibody or nucleic acid testing of infectious agents. All samples were divided into five groups, which were fresh‐frozen group (control group), 15 kGy gamma irradiation group, 25 kGy gamma irradiation group, 70% ethanol group, and peracetic acid‐ethanol group. Each group included 10 tendons for testing. Histological staining and transmission electron microscopy were applied to observe the internal structure and arrangement of tendon collagen fibers, while the machine learning classifier was trained to distinguish the darker cross‐sections of collagen fibers and brighter backgrounds of the electron micrograph to detect the distribution of diameters of tendon collagen fibers. The viscoelasticity, mechanical properties and material properties of tendon allografts were examined to detect the influence of different intervention factors on the biomechanical properties of tendons.Results: Histological staining and transmission electron microscopy showed that the structure of fresh‐frozen tendons was similar to the structures of other experimental groups, and no obvious fiber disorder or delamination was observed. In the uniaxial cyclic test, the cyclic creep of 25 kGy irradiation group (1.5%) and peracetic acid‐ethanol group (1.5%) were significantly lower than that of the control group (3.6%, F = 1.52, P = 0.039) while in the load‐to‐failure test, the maximum elongation and maximum strain of the peracetic acid‐ethanol group were significantly higher than those of the control group (F = 4.60, P = 0.010), and there was no significant difference in other biomechanical indicators. According to the experimental results of denatured collagen, it could be seen that no matter which disinfection procedure was used, the denaturation of the tendon sample would be promoted (F = 1.97, P = 0.186), and high‐dose irradiation seemed to cause more damage to collagen fibers than the other two disinfection procedures (296.2 vs 171.1 vs 212.9 μg/g).Conclusion: Biomechanical experiments and collagen denaturation tests showed that 15 kGy gamma irradiation and 70% ethanol can preserve the biomechanical strength and biochemical properties of tendons to the greatest extent, and these two sterilization methods are worthy of further promotion.

Objective: To compare the biomechanical properties of percutaneous cement discoplasty (PCD) in the spinal column between different implant‐endplate friction.Methods: A validated L3‐Scarumfinite element (FE) model was modified for simulation. In the PCD model, the L4/5 level was modified based on model 1 (M1) and model 2 (M2). In M1, the interaction between bone cement and endplate was defined as face‐to‐face contact with a friction coefficient of 0.3; in M2, the contact was defined as a Tie constraint. 7.5 N m moments of four physiological motions and axial load of 15, 100 and 400 N preload were imposed at the top of L3. The range of motion (ROM) and interface stress analysis of endplates, annulus fibrosus and bone cement of the operated level were calculated for comparisons among the three models.Results: The ROM of M1 and M2 increased when compared with the intact model during flexion (FL) (17.5% vs 10.0%), extension (EX) (8.8% vs −8.8%), left bending (LB) (19.0% vs −17.2%) and left axial rotation (LR) (34.6% vs −3.8%). The stress of annulus fibrosus in M1 and M2 decreased in FL (−48.4% vs −57.5%), EX (−25.7% vs −14.7%), LB (−47.5% vs −52.4%), LR (−61.4% vs −68.7%) and axis loading of 100 N (−41.5% vs −15.3%), and 400 N (−27.9% vs −27.3%). The stress of upper endplate of M1 and M2 increased in FL (24.6% vs 24.7%), LB (82.2% vs 89.5%), LR (119% vs 62.4%) and axis loading of 100 N (64.6% vs 45.5%), and 400 N (58.2% vs 24.3%), but was similar in EX (2.9% vs 0.3%). The stress of lower endplate of M1 and M2 increased in FL (170.9% vs 175.0%), EX (180.8% vs 207.7%), LB (302.6% vs 274.7%), LR (332.4% vs 132.8%) and axis loading of 100 N (350.7% vs 168.6%), and 400 N (165.2% vs 106.7%).Conclusion: Percutaneous cement discoplasty procedure could make effect on the mobility or stiffness. The fusion of bone cement and endplate might have more biomechanical advantages, including of the decreasing rate of implant subsidence and dislocation, and the increase spine stability.