Objectives:To construct the “safe core” of the pedicle screw trajectory using CT imaging data of the subaxial cervical spine in adults, and to assess the accuracy and feasibility of the pedicle screw insertion assisted with the “safe core-referred technique” for subaxial cervical spine with a cadaver specimen study.Methods:This is an experimental study. From January 2015 to March 2020,60 adults′ CT images data of the cervical spine were collected from the database of the First Affiliated Hospital of Gannan Medical University,and were imported into Mimics 20.0 software. Virtual cervical pedicle trajectory and safe core were constructed according to the self-designed “virtual construction method of pedicle in the subaxial cervical spine”. The success rate of the construction and the spatial position data of the virtual safe core of was recorded,including the distance between the safe core and the tangent line of the upper and lower outer edge of Luschka′s joint on coronal plane,and the distance between the safe core and the posterior edge of the vertebral body on sagittal plane.The 3.5 mm column was used to simulate the pedicle screw placement,using the safe core as the only hub in pedicle screw trajectory.The length of the anterior pedicle screw trajectory,the interval of the abductive angle of the pedicle screw in axial plane, and the projection area of the entry area on periapical radiograph was calculated.In addition,8 adult cervical cadaver specimens were collected for the pedicle screw insertion experiment.The left side group used the “safe core-referred technique” for pedicle screw insertion,while the right side group used the Abumi method for pedicle screw insertion.The accuracy of pedicle screw placement was verified by CT scan.The difference between the accuracy of subjective judgment based on X-ray monitoring of operator and the actual accuracy of pedicle screw insertion verified by CT scan was compared between the two groups.The chi-square test was used to compare the intergroup data.Results:The total success rate of the virtual construction method for the safe core of the subaxial cervical spine was 97.0% (291/300); The distance between the safe core and the tangent line of the upper and lower outer edge of Luschka′s joint on coronal plane was ( M(IQR)) 0.91 (0.98) mm (range: 0 to 1.85 mm);The distance between the safe core and the posterior wall on the sagittal plane of the vertebral body was (2.01±0.86) mm (range: 0.67 to 3.53 mm). The distance (anterior pedicle screw trajectory) from the posterior cortex to the central point of the safe core was (11.58±1.00)mm (range: 8.27 to 14.93 mm).The projection area of the entry point on the coronal plane was (36.18±11.67) mm 2 (range: 13.38 to 83.11 mm 2). Pedicle screw insertion experiment in cervical cadaver specimen showed the rate of intraoperative correction of the pedicle screw trajectory was 7.5% (3/40) in the experimental group and 12.5% (5/40) in the control group ( χ2=0.139, P=0.709). The operator ′s correct rate of subjective judgment on CT in the stage of pedicle screw trajectory preparation was 100% (40/40) in the experimental group and 82.5% (33/40) in the control group, the difference was statistically significant ( χ2=5.638, P=0.018). The actual correct rate of CT verification in the stage of pedicle screw insertion was 100% (40/40) in the experimental group and 90.0% (36/40) in the control group, the difference was statistically significant ( χ2=2.368, P=0.124); The operator ′s correct rate of subjective judgment in the stage of pedicle screw insertion completion was 100% (83/83) in the experimental group and 92.9% (79/85) in the control group ( χ2=4.199, P=0.040). Conclusions:The virtual safe-core of subaxial cervical spine can be use as a reliable anatomical fluoroscopy landmark for freehand pedicle screw insertion.“Safe core-referred technique” can improve the accuracy rate of the operator′s subjective judgment on the intraoperative fluoroscopy monitoring,and hence improve the accuracy of freehand pedicle screw insertion technology for subaxial cervical spine. And it still needs to be further verified in clinical practice.

Objective·To explore the effects and possible molecular mechanisms of nanoplastics(NPs)on severe asthma.Methods·A mouse model of severe asthma was established by using house dust mite(HDM)and lipopolysaccharide(LPS)co-stimulation.Polystyrene nanoplastics(PS-NPs)were instilled into the severe asthma mice's airways.Subsequently,bronchoalveolar lavage fluid(BALF)was collected and lung tissue sections were prepared.Flow cytometry,hematoxylin-eosin(H-E)staining,periodic acid-Schiff(PAS)staining,immunohistochemistry,and terminal dexynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL)staining,were used to observe the effects of PS-NPs on airway inflammation,mucus secretion,alveolar structure,and the proliferation and apoptosis of alveolar type Ⅱ epithelial cells(AT2 cells)in severe asthma mice.The CCK-8 assay and Annexin Ⅴ/PI double staining were performed to evaluate the effects of PS-NPs on the proliferation and apoptosis of the mouse AT2 cell line MLE-12.DNA damage in AT2 cells caused by PS-NPs was detected by using anti-γ-H2A.X immunofluorescence staining.The expression of genes in the ATR/Chk1/p53 signaling pathway was detected by real-time fluorescent quantitative polymerase chain reaction(qPCR),Western blotting,Tyramide signal amplification(TSA)multiplex immunofluorescence staining,and immunofluorescence co-localization,respectively.The ATR-specific inhibitor Ceralasertib(AZD6738)was administrated to MLE-12 cells in combination with PS-NPs to evaluate the recovery effect on cell proliferation and apoptosis.Results·Flow cytometry revealed that exposure to PS-NPs increased the total number of inflammatory cells and the number of each type of inflammatory cells in the BALF of mice with severe asthma,with a predominance of neutrophils.H-E and PAS staining showed significant increase in airway inflammatory cell infiltration and mucus secretion,as well as disruption of alveolar structure.In vitro,the CCK-8 assay demonstrated significant,dose-dependent inhibition of MLE-12 cell proliferation by PS-NPs.The Annexin V/PI double staining assay indicated a higher apoptosis rate of(56.20±3.84)%in PS-NP-exposed cells compared to(23.22±2.52)%in the control group.Immunofluorescence staining demonstrated that PS-NPs were phagocytosed by MLE-12 cells and localized around the nucleus.TUNEL staining confirmed enhanced apoptosis in AT2 cells in vivo.The immunofluorescence assay revealed that compared to the control group,the expression of the DNA damage marker γ-H2A.X increased in the experimental group.qPCR,Western blotting,and TSA multiplex staining results showed that PS-NP-induced elevated expression of mRNA and proteins was related to the ATR/Chk1/p53 pathway in MLE-12 cells.Moreover,immunofluorescence co-localization also confirmed the induction of ATR and p53 proteins in AT2 cells in vivo.The ATR-specific inhibitor Ceralasertib partially restored the PS-NP-induced inhibition of cell proliferation and enhancement of apoptosis in MLE-12 cells.Conclusion·NPs exposure leads to DNA damage in AT2 cells,activating the ATR/Chk1/p53 signaling pathway and exacerbating airway inflammation and alveolar damage in mice with severe asthma.

Objective To investigate the biomechanical properties of a novel sacroiliac lag screw with a spiral blade.Methods Percutaneous sacroiliac lag screws were used as the controls.Polyurethane material was used to simulate the trabecular bone,and the pullout resistance performance was tested on an Instron mechanical testing machine.Subsequently,pelvic specimens were utilized to analyze the static stiffness and dynamic stability of the novel sacroiliac lag screw in repairing sacroiliac joint injuries under normal standing conditions,with normal pelvis,single-sided sacroiliac joint injury pelvis,percutaneous sacroiliac lag screw-single screw repair,and percutaneous sacroiliac lag screw-double screw repair as controls.Results The damage to the polyurethane material after screw extraction was smaller in the novel sacroiliac lag screw group.The average effective holding displacement of the novel sacroiliac lag screw was significantly greater than that of the percutaneous sacroiliac lag screw(P＜0.05).However,the maximum resistance to the pullout force for the percutaneous sacroiliac lag screw was significantly higher than that for the novel sacroiliac lag screw(P＜0.05).The stiffness after repair of sacroiliac joint injuries was significantly higher when using a single sacroiliac lag screw than when using two percutaneous sacroiliac lag screws(P＜0.05).The displacement amplitude was the highest in the sacroiliac joint injury group,followed by that in the normal group.The displacement amplitudes in the other groups were similar;however,the differences were statistically significant(P＜0.05).The dynamic stability of the sacroiliac lag screw repair group was the best,slightly better than that of the percutaneous sacroiliac lag screw-double screw repair group,and the dynamic stability of the sacroiliac joint injury group was the worst.The novel sacroiliac lag screw effectively repaired the sacroiliac joint injuries.Conclusions The novel sacroiliac lag screw can effectively hold the trabecular bone and has practical clinical utility.

OBJECTIVE To explore the correlation between early clinical auditory brainstem response and long-term temporal bone development in patients with microtia and atresia. METHODS A retrospective review of clinical data of patients with MA,including ABR examination results in infancy,temporal bone CT results in adolescence and childhood,and basic demographic information. Comparison of ABR thresholds among patients with different temporal bone development statuses. RESULTS Jahrsdoerfer score and the degree of mastoid pneumatization were negatively correlated with ABR air conduction threshold and air-bone gap. The Jahrsdoerfer high score group of patients with congenital aural atresia had significantly lower ABR air conduction threshold(P=0.011) and ABR air-bone gap(P=0.033) than the low Jahrsdoerfer score group. The air conduction threshold(P=0.005) and air-bone gap(P<0.001) of ABR in mastoid process of pneumatic group were lower than those in non-pneumatic group in all patients with MA. The ABR air-conduction threshold(P=0.002) and ABR air-bone gap(P<0.001) in the congenital aural stenosis with cholesteatoma group were higher than those in the non-cholesteatoma group. CONCLUSION For patients with MA,ABR examination in infancy not only reflects the patients' hearing status but also has predictive value for temporal bone development.

Objective:Age-related cataract is the most common type of adult cataract and a leading cause of blindness.Currently,there are few reports on the establishment of animal models for age-related cataract.During the experimental breeding of Microtus fortis(M.fortis),we first observed that M.fortis aged 12 to 15 months could naturally develop cataracts.This study aims to explore the possibility of developing them as an animal model for age-related cataract via identifing and analyzing spontaneous cataract in M.fortis. Methods:The 12-month-old healthy M.fortis were served as a control group and 12-month-old cataractous M.fortis were served as an experimental group.The lens transparency was observed using the slit-lamp biomicroscope.Hematoxylin and eosin staining was used to detect pathological changes in the lens.Biochemical detection methods were applied to detect blood routine,blood glucose levels,the serum activities of superoxide dismutase(SOD),and glutathione peroxidase(GSH-Px)in both groups.Finally,real-time RT-PCR was used to detect the transcription levels of cataract-related genes in the lens of 2 groups. Results:Compared with the control group,the lens of cataract M.fortis showed severely visible opacity,the structure of lens was destroyed seriously,and some pathological damage,such as swelling,degeneration/necrosis,calcification,hyperplasia,and fiber liquefaction were found in lens epithelial cells(LECs).The fibrous structure was disorganized and irregularly distributed with morgagnian globules(MGs)aggregated in the degenerated lens fibers.There was no statistically significant difference in blood glucose levels between the experimental and control groups(P＞0.05).However,white blood cell(WBC)count(P＜0.05),lymphocyte count(P＜0.01),and lymphocyte ratio(P＜0.05)were significantly decreased,while neutrophil percentage(P＜0.05)and monocyte ratio(P＜0.01)were significantly increased.The serum activities of SOD and GSH-Px(both P＜0.05)were both reduced.The mRNAs of cataract-related genes,including CRYAA,CRYBA1,CRYBB3,Bsfp1,GJA3,CRYBA2,MIP,HspB1,DNase2B,and GJA8,were significantly downregultaed in the lenses of the experimental group(all P＜0.05). Conclusion:There are significant differences in lens pathological changes,peroxidase levels,and cataract-related gene expression between cataract and healthy M.fortis.The developed cataract spontaneously in M.fortis is closely related to age,the cataract M.fortis might be an ideal animal model for the research of age-related cataract.

BACKGROUND:For dislocation of acromioclavicular joint induced by coracoclavicular ligament fracture,single EndoButton Plate reconstruction and double EndoButton Plates reconstruction are common repair methods.Further study on the stress distribution and fracture risk of the two repair methods is of great significance. OBJECTIVE:To study the biomechanical properties of the coracoclavicular ligament,and compare the fixation effect,stress distribution and failure mode of single and double EndoButton Plates reconstruction. METHODS:(1)Finite element simulation analysis:Mimics,Wrap and SolidWorks were used to establish normal coracoclavicular ligament,single EndoButton Plate reconstruction and double EndoButton Plates reconstruction.Ansys software was used to analyze the stress and deformation of the scapula and clavicle of each model under vertical load.(2)Sample experiment:Fifteen intact scapular-clavicle specimens were randomly grouped into five groups,with three specimens in each group.In group A,the acromioclavicular ligament was severed and the coracoclavicular ligament remained intact.In group B,acromioclavicular ligaments and trapeoid ligaments were severed,leaving intact conical ligaments.In group C,acromioclavicular ligaments and conical ligaments were cut off,and the intact traprex ligaments were retained.In group D,acromioclavicular and coracoclavicular ligaments were severed,and coracoclavicular ligaments were repaired by single EndoButton Plate reconstruction.In group E,acromioclavicular and coracoclavicular ligaments were severed,and the coracoclavicular ligaments were repaired by double EndoButton Plates reconstruction.The mechanical experiment was carried out by a mechanical testing machine to analyze the biomechanical status,stress distribution and failure patterns of the scapular-clavicle and clavicle. RESULTS AND CONCLUSION:(1)Finite element simulation analysis:The average stress of coracoclavicular ligament attached specimens was the lowest,and the risk of coracoclavicular fracture was less than that of single and double EndoButton Plates reconstruction.The mean stress of the coracoid process was similar in single and double EndoButton Plates reconstruction,and the fracture risk was similar.(2)Sample experiment:In groups A,B,C,D and E,the stiffness of specimens was(26.4±3.5),(19.8±2.8),(21.3±3.2),(57.7±4.1),and(46.2±2.8)N/mm,respectively;the ultimate loads were(545.5±53.7),(360.1±42.1),(250.9±44.4),(643.5±39.1),and(511.9±31.7)N,respectively;global stiffness in groups D and E was higher than that in group A(P=0.000 06,0.000 3);ultimate load in group D was higher than that in group A(P<0.05);the ultimate load was not significantly different between the group E and group A(P>0.05).Ligament fracture was observed in groups A,B and C and coracoid process fracture was found in groups D and E.(3)These results suggest that from the biomechanical analysis,Single EndoButton Plate reconstruction and double EndoButton Plates reconstruction are effective treatment techniques for coracoclavicular ligament fracture in acromioclavicular joint dislocation,but increase the risk of fracture.The double EndoButton Plates reconstruction dispersed the stress of the steel plate and reduced the contact force between the steel plate and bone,but slightly reduced the ultimate bearing capacity.Single and double EndoButton Plates reconstruction should be selected according to the actual clinical situation.

BACKGROUND:The stability of the pelvis is mainly determined by the posterior pelvic ring and the sacroiliac joint.The posterior pelvic ring injury and the dislocation of the sacroiliac joint caused by high energy impacts such as car accidents increase year by year.Surgical treatment is the best method,and there are many kinds of endophytorepair methods in clinical practice,but which treatment method has the best biomechanical properties is still controversial. OBJECTIVE:To compare the biomechanical properties of three kinds of internal implants:anterior double plates,posterior bridging plate and tension nail in the repair of unilateral unstable pelvic posterior ring injury,to provide a reference for the clinical treatment and development of a new pelvic tension screw. METHODS:(1)Finite element simulation:Mimics,Wrap and SolidWorks were used to establish normal pelvic model,unilateral injured pelvis model,and three kinds of internal implant repaired models(anterior double plates,posterior bridging plate and tension nail).Ansys was used to analyze the stress and deformation of the models.(2)Biomechanical test:A total of 15 intact pelvic specimens were randomly grouped into five groups,normal pelvic model,unilateral injured pelvis model,anterior double plates,posterior bridging plate and tension nail groups.The mechanical test was performed using an Instron E10000 testing machine. RESULTS AND CONCLUSION:(1)Simulation:In the normal pelvic model,the average displacement of the sacrum was 0.174 mm,and the maximum stress of the sacral iliac bone was 10.51 MPa,and the stress distribution was uniform.The mean sacral displacement of the unilateral injured pelvis model was 0.267 mm,and the stress concentration of the model was obvious.The mean displacement of the sacrum in the three repaired models was close to that in the normal pelvic model,and the stress distribution of the sacral iliac bone in the tension nail repaired model was uniform.(2)Mechanical test:The stiffness of the normal pelvic model was(226.38±4.18)N/mm,and that of the unilateral unstable pelvic model was the smallest(130.02±2.19)N/mm.The deviation of the normal pelvic model stiffness and the three repaired models'stiffness were all within(±10%),and the repair effect was obvious.(3)The simulation results were in agreement with the experimental results.(4)The biomechanics of the tension nail repaired model was the most similar to that of the normal pelvis,and this method was the best.The repairing stiffness of the anterior double plate was too large,and the stress shielding effect was more significant.The posterior bridging plate repair could not solve the compensatory effect of the normal side soft tissue and had defects.This study provides an optimal basis for clinical surgery.(5)The new type of pelvic tension nail should be improved from the point of view of the tension nail to retain the good biomechanical properties of the tension nail,while adding other advantages,such as being used for the osteoporotic pelvis.

Objective:To investigate the risk factors of pleural effusion after spinal separation surgery for patients with spinal metastatic tumors.Methods:A total of 427 patients with spinal metastatic tumors from January 2014 to January 2022 in the Second Affiliated Hospital of Zhejiang University School of Medicine were retrospectively analyzed. There were 252 males and 175 females, with an average age of 59±12 years (range, 15-87 years). All patients underwent separation surgery. Based on the chest CT within 1 month after surgery, the volume of pleural effusion was measured individually by reconstruction software. Pleural effusion was defined as small volume (0-500 ml), moderate volume (500-1 000 ml), and large volume (above 1 000 ml). Baseline data and perioperative clinical outcomes were compared between the groups, and indicators with statistically significant differences were included in a binary logistic regression analysis to determine the independent risk factors for the development of pleural effusion after isolation of spinal metastatic cancer. Receiver operating characteristic (ROC) curves were conducted to calculate the area under the curve (AUC) for each independent risk factor.Results:All patients successfully completed the operation. Among the 427 patients, there were 35 cases of large pleural effusion, 42 cases of moderate pleural effusion, and 350 cases of small pleural effusion. There were significant differences in tumor size (χ 2=9.485, P=0.013), intraoperative blood loss ( Z=-2.503, P=0.011), blood transfusion ( Z=-2.983, P=0.003), preoperative total protein ( Z=2.681, P=0.007), preoperative albumin ( Z=1.720, P= 0.085), postoperative hemoglobin ( t=2.950, P=0.008), postoperative total protein ( Z=4.192, P<0.001), and postoperative albumin ( t=2.268, P=0.032) in the large pleural effusion group versus the small and moderate pleural effusion group. Logistic regression analysis showed that decreased preoperative albumin ( OR=0.89, P=0.045) and metastases located in the thoracic spine ( OR=4.01, P=0.039) were independent risk factors for the occurrence of large pleural effusion after separation surgery. The ROC curve showed that the AUC and 95% CI for preoperative albumin, lesion location, and the combined model were 0.637 (0.54, 0.74), 0.421 (0.36, 0.48), and 0.883 (0.81, 0.92). The combined predictive model showed good predictive value. Conclusion:The volume of pleural effusion can be measured individually and quantitatively based on chest CT. Decreased preoperative albumin and metastases located in the thoracic spine are independent risk factors for the occurrence of large pleural effusion after separation surgery. The combined prediction of the two factors has better predictive efficacy.

Objectives:To construct the “safe core” of the pedicle screw trajectory using CT imaging data of the subaxial cervical spine in adults, and to assess the accuracy and feasibility of the pedicle screw insertion assisted with the “safe core-referred technique” for subaxial cervical spine with a cadaver specimen study.Methods:This is an experimental study. From January 2015 to March 2020,60 adults′ CT images data of the cervical spine were collected from the database of the First Affiliated Hospital of Gannan Medical University,and were imported into Mimics 20.0 software. Virtual cervical pedicle trajectory and safe core were constructed according to the self-designed “virtual construction method of pedicle in the subaxial cervical spine”. The success rate of the construction and the spatial position data of the virtual safe core of was recorded,including the distance between the safe core and the tangent line of the upper and lower outer edge of Luschka′s joint on coronal plane,and the distance between the safe core and the posterior edge of the vertebral body on sagittal plane.The 3.5 mm column was used to simulate the pedicle screw placement,using the safe core as the only hub in pedicle screw trajectory.The length of the anterior pedicle screw trajectory,the interval of the abductive angle of the pedicle screw in axial plane, and the projection area of the entry area on periapical radiograph was calculated.In addition,8 adult cervical cadaver specimens were collected for the pedicle screw insertion experiment.The left side group used the “safe core-referred technique” for pedicle screw insertion,while the right side group used the Abumi method for pedicle screw insertion.The accuracy of pedicle screw placement was verified by CT scan.The difference between the accuracy of subjective judgment based on X-ray monitoring of operator and the actual accuracy of pedicle screw insertion verified by CT scan was compared between the two groups.The chi-square test was used to compare the intergroup data.Results:The total success rate of the virtual construction method for the safe core of the subaxial cervical spine was 97.0% (291/300); The distance between the safe core and the tangent line of the upper and lower outer edge of Luschka′s joint on coronal plane was ( M(IQR)) 0.91 (0.98) mm (range: 0 to 1.85 mm);The distance between the safe core and the posterior wall on the sagittal plane of the vertebral body was (2.01±0.86) mm (range: 0.67 to 3.53 mm). The distance (anterior pedicle screw trajectory) from the posterior cortex to the central point of the safe core was (11.58±1.00)mm (range: 8.27 to 14.93 mm).The projection area of the entry point on the coronal plane was (36.18±11.67) mm 2 (range: 13.38 to 83.11 mm 2). Pedicle screw insertion experiment in cervical cadaver specimen showed the rate of intraoperative correction of the pedicle screw trajectory was 7.5% (3/40) in the experimental group and 12.5% (5/40) in the control group ( χ2=0.139, P=0.709). The operator ′s correct rate of subjective judgment on CT in the stage of pedicle screw trajectory preparation was 100% (40/40) in the experimental group and 82.5% (33/40) in the control group, the difference was statistically significant ( χ2=5.638, P=0.018). The actual correct rate of CT verification in the stage of pedicle screw insertion was 100% (40/40) in the experimental group and 90.0% (36/40) in the control group, the difference was statistically significant ( χ2=2.368, P=0.124); The operator ′s correct rate of subjective judgment in the stage of pedicle screw insertion completion was 100% (83/83) in the experimental group and 92.9% (79/85) in the control group ( χ2=4.199, P=0.040). Conclusions:The virtual safe-core of subaxial cervical spine can be use as a reliable anatomical fluoroscopy landmark for freehand pedicle screw insertion.“Safe core-referred technique” can improve the accuracy rate of the operator′s subjective judgment on the intraoperative fluoroscopy monitoring,and hence improve the accuracy of freehand pedicle screw insertion technology for subaxial cervical spine. And it still needs to be further verified in clinical practice.