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Objective To study the effect of different rod curvature on the postoperative stability and stress of thoracolumbar junction fracture using the finite element simulation.Methods (1) Thoracolumbar finite element model of T11 to L1 from three-dimensional CT data of a 30-year-old healthy male volunteer was established,including the assignment of cortical bone,cancellous bone,disc,ligaments and facet joints.On this basis,the T12fracture model was also established.T11 to L1 bilateral pedicle screw fixation was loaded,and the rod connection was divided into straight rod group and pre-bended rod group (lordotic 15°-25°) according to angle of the rod.A 400 N stress was loaded on the top of the upper endplate of T11 to simulate the upper part body gravity,while applying a 10 N · m torque to generate flexion and extension,lateral flexion and rotation.Stress distribution of different methods of pre-bending for thoracolumbar fractures after reduction was compared.(2) A retrospective cohort analysis was made on 56 cases of thoracolumbar fractures surgically treated from July 2012 to July 2016,including 31 cases in straight rod group and 25 cases in pre-bended rod group.Two groups were compared in angle between adjacent level before operation,after operation and at final follow-up.Results (1) In flexion,extension,lateral bending and rotation,both rod bending methods effectively controlled the thoracolumbar junction displacement.The peak stress of connecting rod (151,315,369,377 MPa respectively) in pre-bended rod group was lower than that in straight rod group (110,239,281,189 MPa respectively) (P ＜ 0.05),and straight rod group appeared relatively obvious stress concentration.(2) Mean follow-up time was 21.4 months (range,4-33 months).Preoperative kyphosis angle was (21.7 ± 7.4)°in straight rod group and (20.3 ± 6.8)° in pre-bended rod group (P ＞ 0.05).Postoperative lordosis angle in straight rod group was (3.3 ± 1.2) °versus (8.3 ± 2.8) ° in pre-bended rod group (P ＜ 0.05).At the final follow-up,the lordosis angle in straight rod group was reduced by (8.7 ± 2.3) ° versus (3.9 ± 1.7)°in pre-bended rod group (P ＜0.05).Implant failure was seen in 3 cases in straight rod group,but there was no implant failure in pre-bended rod group.Conclusion Pre-bended (lordotic 15°-25°) and pre-loaded rods used in internal fixation of thoracolumbar fractures may reduce the stress of rods,decrease the incidence of implant failure and facilitate the recovery of spine stability.
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Objective: To study the correlation between serum resistin (SR) level and blood pressure in patients with type 2 diabetes mellitus (T2DM) complicated hypertension. Methods: A total of 124 patients with T2DM complicated hypertension (T2DM + hypertension group), 85 patients with pure T2DM (pure DM group) and 71 normal subjects (normal control group) were enrolled. According to blood pressure level, T2DM + hypertension group was further divided into stage 1 subgroup (n=34), stage 2 subgroup (n=43) and stage 3 subgroup (n=47). Peripheral venous blood was taken to measure levels of SR and other indexes in three groups. Logistic multi-factor regression analysis was used to analyze the risk factors affecting blood pressure level. Kendall’s tau-b correlation analysis was used to analyze the correlation among SR, fasting insulin, quantitative insulin sensitivity check index, homeostasis model-insulin resistance index and blood pressure level. Results: Compared with normal control group, there were significant rise in SR levels [(7.21±2.65) ng/ml vs. (19.87±3.67) ng/ml vs. (31.32±3.89) ng/ml] in pure DM group and T2DM + hypertension group, and that of T2DM + hypertension group was significantly higher than that of pure DM group, P<0.01 all. Logistic multi-factor regression analysis indicated that SR level was an independent risk factor influencing blood pressure level of patients (R2=0.087, P<0.05). Kendall’ s tau-b correlation analysis indicated that SR level was significantly positively correlated with blood pressure level of patients with hypertension (r=0.202, P=0.001); after other influencing factors were controlled, the significant positive correlation still existed between them (r=0.233, P=0.022). Conclusion: Serum resistin level rise is a risk factor of patients with type 2 diabetes mellitus complicated hypertension, and it is significantly positively correlated with their blood pressure level.
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ObjectiveTo identify the anatomical feasibility of cross screw fixation in the atlas via posterior arch,provide a reference for clinical applications.MethodsA total of 10 dry atlas specimens were used to measure anatomic data and three dimension(3D) CT data.The data included height of the posterior tubercle,width of the posterior arch,distance from the ideal point to the interior of the vertebral artery sulcus,from nail point to central line,and the ideal direction of the screws.Statistical analysis was done to compare the two methods.Then 100 3D CT data were measured.The parameters included height of the posterior tubercle (mid-sagittal plane),width of the posterior arch (the inner side where arch transformed to the vertebral artery sulcus),distance from the ideal point to the interior of the vertebral artery sulcus (where screws completely located in the medullary cavity),distance between the nail point to central line,and angle of the ideal screws (between screws and horizontal line).The anatomy of the atlas was analyzed for whether height of the posterior tubercle is more than 7 mm,width of the posterior arch is more than 3.5 mm,and whether or not cross screws can be planted.ResultsThere was no statistical difference between anatomic and 3D-CT measures.Thickness of the C1 laminar was (4.7±0.9) mm in the left side,(4.6±0.8) mm in the right side,and 93.5％ of specimens were thicker than 3.5 mm.Distance of the ideal screw was(15.9±3.0) mm in the left side,(15.9±3.0) mm in the right side.Height of the C1 posterior tuber was (7.8±1.2) mm,with 91％ of the data higher than 7.0 mm.Angle between the axial of C1 laminar and frontal plane was 26.8°±6.8° (8°-44°) in the left side,26.8°±6.3°(13°-44°) in the right side,and about 11％ of them can not cross plant.ConclusionIt is feasible and safe to place cross screws in the posterior arch of the C1 in anatomy.
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Objective To discuss the complication risk factors for early death after cervical injuries and explore the indication for treatment. Methods A retrospective study was carried out on early death and complications in 419 patients with cervical injuries admitted into our hospital. We observed the relationship of all kinds of complications with cervical cord injury severity and the incidence rate of complications in all patients. Results The respiratory complication was the main cause of early death, accounting for 79.11%. There found complications including hypoalbuminemia ( 85.29% ), hypotension(50%) and hyponatremia ( 35.29% ) in the death patients. Conclusions The existence of complications, especially hypoalbuminemia, can aggravate the original dysfunction and is the risk factor for early death. The early treatment of the dangerous complications could prevent multiple organ failure and early death and provide sound condition for functional recovery.
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Objective To study the safety and efficacy of transpedicular osteotomy en bloc lamina resection to treat thoracic spinal stenosis.Methods A retrospective study of 23 consecutive patients underwent transpedicular osteotomy en bloc lamina resection from June 2004 to December 2008,including 12 males and 11 females,with a mean age of 46 years(range,38-62 years)was conducted.The courses of diseases were 1.5 to 20 months with an average of 6.5 months.There were 18 cases caused by thoracic ossification of ligamentum flavum(OLF),4 cases caused by ossification of posterior longitudinal ligament(OPLL)and 1 case caused chondroma.Preoperative CT and MRI examinations showed that all patients got spinal cord compression.Preoperative ASIA Grade was A for 1 case,B for 3 cases,C for 7 cases and D for 13 cases.Postoperative neurological status was evaluated by ASIA grade system.Results The postoperative follow-up duration ranged from 16 to 58 months(mean 30 months).The operation time varied from 90 to 210 min,with the average of 163 min.Blood loss varied from 600 to 3200 ml,with the average of 2150 ml.Pedicle screws were used in 10 cases with T9-T12 stenosis,and dura excisions were repaired by lumbodorsal fascia in 5 cases.Cerebrospinal fluid leakage occurred in 2 cases.Postoperative ASIA grade showed that there was A for 1 case,B for 2 cases,C for 2 cases,D for 5 cases and E for 13 cases.Conclusion Transpedicular osteotomy is a good approach,which avoid sclerotic cortex and ossified ligamentum flavum,to resect en bloc lamina with with shorter operative time and less blood loss.
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Objective To investigate the methods, feasibility, outcome and indications of atlantoaxial pedicle screw system in the treatment of upper cervical injury. Methods Thirteen patients with upper cervical injury were treated by atlantoaxial pedicle screw system. There were four patients with old odontoid fractures, two with new odontoid fractures (Aderson ⅡC), three with rapture of the transverse ligament of C1 and four with C1 fracture. Results A total of 26 pedicle screws and 26 pedicle screws were implanted. The mean operation time and perioperative blood loss were 2.6 hours and 470 ml, respectively. No injury to the vertebral artery and spinal cord was observed. All patients were followed up for 4-25 months (mean 13 months). The clinical symptoms were improved to some extent according to Japanese Orthopedic Association scoring system, with improvement rate of 72%-91% (mean 81%). The screws were verified to be fixed in a proper position, and no hardware broken or loosening was observed except for one C1 screw penetrating the medial superior cortex of lateral mass for 3 mm without affecting occipito-aflantal motions. All patients had a solid bony fusion 3-6 months later. Conclusion The atlantoaxial pedicle screw system is feasible in the treatment of upper cervical injury with the advantages of better outcomes and wider indications.