Objective:To investigate the anatomical safety and feasibility ofposterior occipitocervical fixation with atlan-tooccipital-clivus screw.Methods:Data of 60 patients who treated in the spinal department of our hospital with upper cervical computed tomographic scans from February 2017 to November 2019 were retrospectively collected. Occipitocervical infection, injury, tumor and deformity were excluded. The Mimics software was used to reconstruct the occiput, atlas and measure the anatomical parameters, including the height and width of the anterior edge of the clivus, the height and width of the middle part of the clivus, the thinnest distance of the soft tissue in front of the clivus, the anteroposterior diameter, transverse diameter, the angle of inside tilting in coronary plane of the occipital condyle, the distance from the hypoglossal canal to the atlantooccipital articular surface, the anteroposterior diameter and transverse diameter of the superior joint of atlas, the height of the lateral mass, and the height and transverse diameter of the inferior articular process of the superior atlas joint. The three-dimensional digital modeling was performed and the screw diameter of 3.5mm was simulated. 3-Matic software were used to measure the screw placement parameters, including the inside tilting angle in coronary plane of screw, and the angle of upper tilting in sagittal plane and length of screw. The atlanto-occipital junction was exposed at the rear of 8 cadavers. According to the above parameters, the titanium alloy screws with a diameter of 3.5 mm were transferred from the inferior articular process and posterior arch of the atlas to the clivus through the atlantooccipital. Finally, the screw path was cut along the nail path with a pendulum saw, and the track of the screw was observed to confirm the safety and effectiveness of the screw.Results:The leading edge height and width of male clivus was 16.8±2.5 mm and 20.1±3.1 mm. The middle part of the clivus was 9.7±2.3 mm and 22.4±3.7 mm. The thinnest soft tissue in front of the clivus was 5.8±1.48 mm. The anteroposterior diameter of the occipital condyle was 19.1±1.9 mm, the transverse diameter was 12.6±2.0 mm, the inside tilting angle was 33.7°±4.5°, and the vertical distance from the lowest point of the neural tube to the articular surface of the occipital condyle was 9.6±1.1 mm. The height of the lateral mass of atlas was 12.9±2.4 mm, the anteroposterior diameter of the upper joint of atlas was 21.7±1.9 mm, and the transverse diameter was 11.7±1.4 mm. The width of the inferior facet was 14.9±1.4 mm and the height of the inferior facet was 5.7±0.85 mm. The distance from the screw entry point to the vertical line of the lateral mass migration midpoint was 2.5±0.6 mm; The distance from the screw entry point to the horizontal line of the midpoint was 2.3±0.7 mm.The inside titling angle of screw was 18.4°±1.6°, the upper tilting angle was 55.6°±3.1°, the length of the screw track was 53.0±2.8 mm, the adjustment range of upper tilting angle was 15.0±2.8 mm, the adjustment range of inside tilting angle was 10.4±2.4 mm. The anatomical parameters of females were slightly smaller than those of males, and the difference was statistically significant, but there was no significant difference between left and right parameters. The screws of 8 specimens could be inserted safely and effectively.Conclusion:Atlan-tooccipital-clivus screw can be implanted without damaging the nerve and vascular structure, and it can be used as a choice for occipitocervical fixation.

The ideal scaffold material can reconstruct the morphology, structure and function of tissues and organs. Thus, it has received extensive attention in the field of tissue engineering. With the rapid development of the theories and technologies of naturally-derived biomaterials, it has gradually become a research hotspot in the field of regenerative medicine. Natural biomaterials have high bionics, good biocompatibility and a wide range of sources. Thus, they are very suitable to be used as scaffolds for tissue engineering. According to ingredients and source of raw materials, they can be roughly divided into protein-based biomaterials (collagen, gelatin, silk and fibrin), carbohydrate-based biomaterials (cellulose, chitin/chitosan, alginate and agarose), glycosaminoglycans (hyaluronic acid, chondroitin sulfate) and decellularized extracellular matrix (amniotic membrane, small intestinal submucosa, tendons). Different scaffold materials have unique natural structures and properties. Protein-based biomaterials can affect cell migration and differentiation through polymerization to form a network structure. They can be made into stents alone or used with other synthetic materials based on certain mechanical properties. Carbohydrate biomaterials can carry a large amount of liquid due to their high specific surface area. However, their mechanical properties are poor. Therefore, it is often used in the form of gel with other materials to control the release of cells and growth factors in tendon tissue engineering. Regularly, the anti-inflammatory, viscoelastic, lubricating and highly hydrating properties of glycosaminoglycan biomaterials can be combined with synthetic materials to increase their biocompatibility and hydrophilicity. Compared with the above materials, the decellularized extracellular matrix not only has a more similar extracellular structure and nutrients, but also has certain mechanical properties. Therefore, it can better reconstruct the morphology, structure and function of tissue and organ lesions. Ultimately, the above materials have been paid more and more attention in tissue engineering. The ingenious combination of different materials makes the repair of tendons show better results. In future, naturally-derived biomaterials could have broader clinical prospects and application value.

Objective:To investigate the safety of posterior atlantoaxial transarticular screw combined with atlas pedicle screw fixation in Chinese.Methods:CT data of upper cervical spine in 48 patients were collected from Ningbo No.6 Hospital, including 26 males and 22 females aged 26-58 years [(37.3±13.5)years]. All CT data was transformed into 3D dimensional model and inserted with virtual screws by Mimics 19.0. Firstly, the vertical plane P 1 and the horizontal plane P 2 of the atlas were built in those atlantoaxial models, secondly the atlantoaxial transarticular screw S 0 was inserted by Margel method, and it's insertion point was located at 3 mm lateral and 2 mm cephalad in the C 2 inferior articular process. Finally, four atlas pedicle screws were inserted at the midline of atlas lateral mass. The four screws are inserted as follows. S 1: the screw was tangent to the lateral side of the S 0 or the medial of the atlas pedicle. S 2: the screw was tangent to the lateral wall of the atlas pedicle. S 3: the screw was tangent to the upper wall of the atlas pedicle. S 4: the screw was tangent to the inferior wall of the atlas pedicle. The angles between S 1, S 2 and P 1 as the camber angle, and the angle between S 3, S 4 and P 2 as the gantry angle were measured. Then the safety range of camber angle and gantry angle were calculated, and the screw length of S 1, S 2, S 3 and S 4 was measured. In all models, the camber angle and gantry angle of the screws were adjusted an interval of 2°, the number of successful cases was calculated and the success rate of insertion was calculated. Results:All 3D models were inserted successfully. The minimum value, maximum value and safety range of the camber angle of atlas pedicle screws were (-6.7±5.2)°, (10.4± 4.3)°, (17.1±3.7)°, respectively; and of the gantry angle were (-0.5±3.5)°, (11.0±5.8)°, (11.5±4.9)°, respectively. The length of screw placement was S 1: (31.1±2.4)mm, S 2: (28.3±2.5)mm, S 3: (29.2±3.8)mm, S 4: (29.6±3.0)mm, respectively ( P<0.05). When the camber angle was from -1°to 5°, the success rate of screw placement was 87.5%; when inserting with 2° camber angle, the success rate was 100%; when the gantry angle was 5°, the success rate was 93.8%. Conclusion:The posterior atlantoaxial transarticular screw combined with atlas pedicle screw can achieve satisfy insertion length and success rate.

Objective: To compare the clinical efficacy of posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or iliac bone graft for atlantoaxial instability. Methods: A retrospective case-control study was conducted to analyze the clinical data of 56 patients with atlantoaxial instability admitted to the Sixth Hospital of Ningbo from September 2014 to October 2016. There were 35 males and 21 females, with the age range from 9 to 59 years [(50.3±3.2)years]. A total of 26 patients were treated with posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft (complex group), while 30 patients were treated with iliac bone graft (ilium group). Patients showed different degrees of neck pain and limited neck activity preoperatively. X-ray films and three-dimensional CT examination of the cervical spine were taken before and after operation for evaluating the atlantoaxial reduction, bone graft fusion and internal fixation. The operation time, intraoperative bleeding, bone fusion time, visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI) and axial symptoms were compared between the two groups, and the complications were recorded. Results: Both groups were followed up for 24-30 months, with an average of 27.4 months. In the complex group and the ilium group, the operation time was (2.21±0.25)hours and (2.72±0.26)hours (P<0.01); the intraoperative blood loss was (227.3±45.4)ml and (277.7±43.4)ml, respectively (P<0.05); the bone fusion time was (6.9±0.5)months and (8.1±1.8)months (P>0.05), respectively. In the complex group, the VAS was (5.45±0.69)points before operation, (2.64±0.51)points at the follow-up one month after operation, (0.91±0.7)points at the follow-up 12 months after operation, and (0.45±0.16)points at the follow-up 24 months after operation; and in the ilium group, the VAS was (5.18±0.75)points, (2.45±0.52)points, (1.27±0.19)points and (0.41±0.18)points correspondingly. In terms of VAS, there were significant differences before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). In the complex group, the JOA score was (10.82±0.35)points before operation, (12.73±0.65)points at the follow-up one month after operation, (15.18±0.61)points at the follow-up 12 months after operation, and (15.64±0.15)points at the follow-up 24 months after operation; and in the ilium group, the JOA score was (10.73±1.19)points, (13.01±0.63)points, (14.73±0.91)points and (15.55±0.51)points correspondingly. In terms of JOA score, there were significant differences between before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). In the complex group, the ADI was (2.28±0.59)mm before operation, (1.83±0.56)mm at the follow-up one month after operation, (1.71±0.56)mm at the follow-up 12 months after operation, and (1.59±0.67)mm at the follow-up 24 months after operation; and in the ilium group, the ADI was (2.23±0.60)mm, (1.80±0.18)mm, (1.67±0.69)mm and (1.62±0.53)mm correspondingly. In terms of ADI, there were significant differences between before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). The axial symptom scores were graded as excellent in 23 patients and good in three patients of the complex group while excellent in 21 patients and good in nine patients in the ilium group (P>0.05). There were no patients with spinal nerve injury caused by pedicle screw placement after operation. One patient in the ilium group had incision errhysis and recovered after dressing change, and other patients had no incision infection. Conclusions For atlantoaxial instability, posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or autogenous iliac bone graft can both achieve satisfactory clinical results. The spinous process-muscle-vascellum complex graft has less operation time and intraoperative bleeding than the autogenous iliac bone graft, which can be a feasible alternative operation.

OBJECTIVE： To systematically evaluate effectiveness and safety of single antiplatelet therapy （SAPT） versus dual antiplatelet therapy （DAPT） on short-term complications after transcatheter aortic valve implantation （TAVI）， and to provide evidence-based reference for clinical treatment. METHODS： Retrieved from PubMed， Cochrane clinical controlled trials registry， Web of Science， CNKI， Wanfang database， CBM and Chinese Clinical Trial Registry， RCTs and observational studies about effectiveness （all-cause mortality， incidence of stroke and incidence of myocardial infarction 30 days after operation） and safety （the incidence of bleeding events at 30 days after operation） of SAPT versus DAPT on short-term complications of TAVI were collected during the date of database establishment to Jan. 2019. After data extraction of included studies and quality evaluation with Cochrane system evaluator manual 5.1.0 （for RCT） and the Newcastle-Ottawa Scale （NOS） （for observational studies）， Meta-analysis was conducted by using Rev Man 5.3 statistical software. RESULTS： Totally 3 RCTs and 7 cohort studies were included， involving 3 188 patients. Results of Meta-analysis showed that the incidence of all-cause mortality 30 days after operation [OR＝0.48， 95％ CI （0.32， 0.73）， P＜0.001] and the incidence of bleeding events 30 days after operation [OR＝0.43， 95％CI （0.30， 0.59）， P＜0.001] in SAPT group were significantly lower than DAPT group， with statistical significance. There was no statistical significance in the incidence of stroke 30 days after operation [OR＝0.63， 95％CI （0.38， 1.06） ， P＝0.08] or the incidence of myocardial infarction 30 days after operation [OR＝1.09， 95％CI （0.46， 2.59）， P＝0.85] between 2 groups. CONCLUSIONS： Compared with DAPT， SAPT can decrease the incidence of all-cause mortality 30 days after TAVI and the incidence of bleeding events 30 days after TAVI.

OBJECTIVE： To systematically evaluate the effects of dual-antiplatelet medication time on efficacy and safety of postoperative complications after transcatheter aortic valve implantation （TAVI）， and to provide evidence-based reference for the formulation of antiplatelet therapy after TAVI. METHODS： Retrieved from Cochrane clinical controlled trial registration center， PubMed， Embase， Web of Science， Wanfang database and CJFD， during database establishment to Feb. 2019， RCTs and observational study about efficacy （all-cause mortality and incidence of stroke） and  safety （the incidence of major bleeding events） the effects of dual-antiplatelet therapy for postoperative complications after TAVI at different time points were collected. After data extraction of clinical studies met inclusion criteria， quality evaluation with Cochrane bias risk evaluation tool 5.1.0 （for RCT） or Newcastle- Ottawa Scale （for observational study）， Meta-analysis was conducted by using Rev Man 5.3 and Stata 14.0 statistical software. Meta-regression analysis was also conducted for outcome and different treatment duration. RESULTS： A total of 3 RCTs and 10 observational studies were included， involving 2 868 patients. The results of Meta-analysis showed that the incidence of all-cause mortality one month and 6 months after medication were 0.05 [95％CI （0.03， 0.07）， P＜0.001] and 0.07 [95％CI （0.05， 0.08）， P＜0.001]. The incidence of major bleeding events 1， 3 and 6 months after medication were 0.14 [95％CI （0.08，0.19）， P＜0.001]， 0.11 [95％CI （0.03， 0.19）， P＝0.007] and 0.13 [95％CI （0.05， 0.22）， P＝0.002]. The incidence of stroke after one month after medication was 0.04 [95％CI （0.03， 0.05）， P＜0.001]. Results of Meta-regression analysis showed that the all-caused mortality [regression coefficient＝0.005 7， 95％CI （－0.001 6， 0.013 0）， P＝0.116]， major bleeding [regression coefficient＝－0.000 5，95％CI（－0.022 4，0.021 4）， P＝0.959] or the incidence of stroke [regression coefficient＝0.001 4， 95％CI （－0.003 8， 0.006 5）， P＝0.570] were not related to medication duration of dual-antiplatelet therapy.  CONCLUSIONS： The prolongation of the medication time of the dual-antiplatelet therapy has no significant effect on the efficacy and safety of TAVI.

Objective: To investigate the efficacy of microscope-assisted free-hand atlantal pedicle screw technique for unstable atlas burst fracture. Methods: A retrospective case control study was conducted to analyze the clinical data of 48 patients with unstable atlas burst fracture admitted to Ningbo No.6 hospital from January 2016 to June 2018. There were 32 males and 16 females, aged 24-72 years [(49.5±15.2 years)]. A total of 22 patients were treated with the technique of atlas screw placement by drill under microscope (Group A), including 14 males and eight females, aged 24-68 years. Twenty six patients (Group B) were treated with atlantal pedicle screw placement by hand, including 18 males and 8 females, aged 26-72 years [(50.7±15.4 years)]. The operation time, intraoperative blood loss and the times of intraoperative fluoroscopy were compared between the two groups. X-ray and CT were reexamined to evaluate the accuracy of screw placement within one week after operation. The visual analogue score (VAS) and cervical dysfunction index (NDI) were compared before operation and 1 year after operation. The intraoperative complications were recorded. One year after operation, X-ray and CT were reexamined to observe fracture healing, atlantoaxial fusion and failure of internal fixation. Results: Group A was followed up for 12-24 months [(18.4±6.8)months], and Group B for 12-24 months [(17.4±7.2)months]. The amount of intraoperative bleeding [(180.5±60.8) ml] and the times of intraoperative fluoroscopy [(1.3±0.8) times] in Group A were significantly lower than those in Group B [(280.1±80.2) ml, (2.2±0.8) times] (P<0.05), but there was no significant difference in the time of operation and the accuracy of screw placement (P>0.05). There were statistically significant differences in VAS and NDI before operation and one year after operation in both groups (P<0.05), but there was no significant difference between the two groups (P>0.05). No serious complications such as vertebral artery, nerve root and spinal cord injury occurred. One year follow-up CT showed healed fracture or continuous bone bridge passing through the atlantoaxial intervertebral space. Except for one patient in Group B with lost reduction, other patients had no loosening or fracture of internal fixation. Conclusion Compared with screw placement by hand, the pedicle screw placement by drill under the microscope can reduce the amount of bleeding and the times of fluoroscopy.

Objective: To investigate the prognostic value of N-terminal B-type natriuretic peptide (NT-proBNP) on all-cause mortality in heart failure patients with preserved ejection fraction (HFpEF) at real world scenarios. Methods: Patients who met the diagnostic criteria of HFpEF in the China National Heart Failure Registration Study (CN-HF) were divided into death and survival groups. The demographic data, physical examination, results of the first echocardiography, laboratory results at admission, complications, drug use and clinical outcomes were obtained from CN-HF. The univariate Cox proportional hazard model was used to screen the variates that might predict prognosis, and then the covariates with statistical significance were included in the multivariate Cox regression model to analyze the predictive value of baseline NT-proBNP on all-cause death. Spearman correlation analysis was used to evaluate the relationship between NT-proBNP and estimated glomerular filtration rate (eGFR), so as to further explore the predictive value of the interaction between renal dysfunction and NT-proBNP on death. Since NT-proBNP did not obey the binary normal distribution, it was expressed by the natural logarithm of NT-proBNP (LnNT-proBNP). Results: A total of 1 846 HFpEF patients were enrolled in this study, with an average age of 71.5 years, 1 017 males(55.1%), median NT-proBNP 860 ng/L, and median eGFR 73.9 ml·min^-1·1.73m^-2. After a median follow-up of 34 months, 213 (11.5%) patients died. Patients in the death group were older, with higher NYHA classification Ⅲ-Ⅳ ratio, longer hospital stay, higher serum potassium and NT-proBNP level, prevalence of complications of diabetes mellitus, arrhythmia and atrial fibrillation, use of angiotensin receptor antagonist(ARB), mineralocorticoid receptor antagonists (MRA), diuretic and digoxin was significantly higher in death group than in survival group. Body mass index (BMI), diastolic blood pressure, left ventricular ejection fraction (LVEF), hemoglobin, serum cholesterol(TC), serum triglycerides (TG) and eGFR, and use of angiotensin converting enzyme inhibitors (ACEI), statins and aspirin were lower in death group than in survival group. Univariate Cox regression analysis showed that NT-proBNP was a predictor of all-cause death in HFpEF patients (HR=2.522, 95%CI 2.040-3.119, P<0.001). Multivariate Cox regression analysis showed that the elevated NT-proBNP remains as the independent predictor of all-cause death in patients with HFpEF (HR=1.230, 95%CI 1.049-1.442, P=0.011) after adjusting for age, BMI, diastolic blood pressure, LVEF, hemoglobin, serum potassium, serum sodium, TC, serum high-density lipoprotein cholesterol (HDL-C), TG, eGFR, atrial fibrillation, as well as the treatment of ACEI/ARB, MRA, diuretics and digoxin. Spearman correlation analysis showed that LnNT-proBNP was negatively correlated with eGFR (r=-0.361, P<0.001), but there was no interaction between NT-proBNP and renal dysfunction in predicting death in HFpEF patients (P>0.05). Conclusion The elevated level of NT-proBNP at admission is an independent predictor of all-cause mortality in HFpEF patients.

The biocompatible hydrogel was fabricated under suitable conditions with natural dextran and polyethylene glycol (PEG) as the reaction materials. The oligomer (Dex-AI) was firstly synthesized with dextran and allylisocyanate (AI). This Dex-AI was then reacted with poly (ethyleneglycoldiacrylate) (PEGDA) under the mass ratio of 4∶6 to get hydrogel (DP) with the maximum water absorption of 810%. This hydrogel was grafted onto the surface of medical catheter via diphenyl ketone treatment under ultraviolet (UV) initiator. The surface contact angle became lower from (97 ± 6.1)° to (25 ± 4.2)° after the catheter surface was grafted with hydrogel DP, which suggests that the catheter possesses super hydrophilicity with hydrogel grafting. The evaluation after they were implanted into ICR rats subcutaneously verified that this catheter had less serious inflammation and possessed better histocompatibility comparing with the untreated medical catheter. Therefore, it could be concluded that hydrogel grafting is a good technology for patients to reduce inflammation due to catheter implantation, esp. for the case of retention in body for a relative long time.
Allyl Compounds ; Animals ; Biocompatible Materials ; Catheters ; Dextrans ; Hydrogel, Polyethylene Glycol Dimethacrylate ; Hydrogels ; Hydrophobic and Hydrophilic Interactions ; Isocyanates ; Polyethylene Glycols ; Rats ; Water

Objective To explore the biomechanical properties of posterior occipital condyle screws compared with common occipitocervical fusion internal fixation and it's impacts upon stress of hypoglossal canals.Methods Finite element models based on the occipitocervical CT data of one 28-year-old male healthy volunteer were built,including normal model,instability model,internal fixation model by occipital condyle screws,internal fixation model by occipital plate screws,and internal fixation model by transarticular screws.Fifty N gravity and 1.5 N · m torque were exerted upon the surface of occipital bone so that the models could perform lateral bending,flexion,extension,and rotational motions.The motion range and stress distribution of internal fixation were compared under varying conditions among different occipitocervical fusion models.In addition,the impact of occipital condyle screw upon hypoglossal canals was examined.Results Compared with instability model,the motion range in the internal fixation model by occipital condyle screws declined by 96.8％,95.6％,95.0％ and 98.5％ respectively in lateral bending,flexion,extension and rotation.In the internal fixation by occipital plate screws,the motion range decreased by 96.3％,95.7％,98.4％ and 99.6％ respectively.In the internal fixation by transarticular screws,the motion range exhibited a decline of 95.7％,94.0％,94.3％ and 98.9％,respectively.The stress peaks in the occipital condyle screw were 192.4 MPa,201.6 MPa and 187.6 MPa under lateral bending,flexion,and rotation conditions,respectively.The stress peaks in the occipital plate screw were 279.6 MPa,213.7 MPa,and 154.1 MPa,respectively.The stress peaks in the transarticular screw were 232.4 MPa,220.9 MPa,and 224.5 MPa,respectively.The stress impact peak of occipital condyle screw on the hypoglossal canals wall was 12.96 MPa,and the content deformationunder the hypoglossal canal was 0.64％.Conclusions The occipital condyle screw internal fixation has similar stability with common occipitocervical fusion fixations.The occipital condyle screw has more uniform stress distribution and less effect on the hypoglossal canals,and hence is safe and reliable as anchor point on the cranial side in occipitocervical fusion.