ABSTRACT
Bone cement-augmented pedicle screw system demonstrates great efficacy in spinal disease treatments. However, the intrinsic drawbacks associated with clinically used polymethylmethacrylate (PMMA) cement demands for new bone cement formulations. On the basis of our previous studies, a novel injectable and biodegradable calcium phosphate-based nanocomposite (CPN) for the augmentation of pedicle screw fixation was systematically evaluated for its surgical feasibility and biomechanical performance by simulated and animal osteoporotic bone models, and the results were compared with those of clinical PMMA cement. ASTM-standard solid foam and open-cell foam models and decalcified sheep vertebra models were employed to evaluate the augmentation effects of CPN on bone tissue and on the cement-injected cannulated pedicle screws (CICPs) placed in osteoporotic bone. Surgical factors in CICPs application, such as injection force, tapping technique, screw diameter, and pedicle screw loosening scenarios, were studied in comparison with those in PMMA. When directly injected to the solid foam model, CPN revealed an identical augmentation effect to that of PMMA, as shown by the similar compressive strengths (0.73 ± 0.04 MPa for CPN group vs. 0.79 ± 0.02 MPa for PMMA group). The average injection force of CPN at approximately 40-50 N was higher than that of PMMA at approximately 20 N. Although both values are acceptable to surgeons, CPN revealed a more consistent injection force pattern than did PMMA. The dispersing and anti-pullout ability of CPN were not affected by the surgical factors of tapping technique and screw diameter. The axial pullout strength of CPN evaluated by the decalcified sheep vertebra model revealed a similar augmentation level as that of PMMA (1351.6 ± 324.2 N for CPN vs. 1459.7 ± 304.4 N for PMMA). The promising results of CPN clearly suggest its potential for replacing PMMA in CICPs augmentation application and the benefits of further study and development for clinical uses.
ABSTRACT
Objective To compare the effects of platelet rich fibrin(PRF)and concentrated growth factors(CGF)using Schwann cells as a pe?ripheral nerve model. Methods A total of 10 healthy volunteers aged 18 to 55 were randomly selected,and 10 mL venous blood was collected un?der aseptic conditions to prepare PRF and CGF. The cells were randomly divided into three groups,control group,PRF group and CGF group. The cell morphology was observed by inverted phase contrast microscope. The cell proliferation was analyzed by MTT assay. The secretion of nerve growth factor in supernatant was detected by enzyme?linked immunosorbent assay. Cell cycle was detected by flow cytometry. Results There was no significant difference of the morphology of cells in each group as observed under inverted phase contrast microscope. MTT results showed that the absorbance values of PRF group and CGF group were significantly higher than those of the control group(P<0.05). The secretion of nerve growth factor in the supernatant were significantly increased(P<0.05). The number of cells in S+G2M phase was significantly increased(P<0.01),but there was no significant difference between PRF group and CGF group. Conclusion Both PRF and CGF can promote proliferation of Schwann cells and increased the amount of nerve growth factor secretion ,but there is no significant difference between PRF and CGF in terms of improving cell proliferation and promoting nerve growth factor secretion.
ABSTRACT
Objective To investigate the efficacy of acupuncture combined with doctor-nurse cooperation mode on stroke-associated pneumonia in patients with acute stroke. Methods 67 patients of acute stroke within 1 week in our hospital from March, 2013 to January, 2015 were randomly divided into control group (n=35) and treatment group (n=32). Both groups received neurological routine treatment and systematic rehabilitation training by professional physiotherapists under general nursing mode. The treatment group received acupuncture treatment under doctor-nurse cooperation mode additionally. Incidence of stroke-associated pneumonia, swallow function and aspiration rate were recorded. Results Compared with the control group, the incidence of stroke-associated pneumonia significantly decreased in the treat-ment group after treatment (χ2=4.615, P=0.032). The retention volume of epiglottic vallecula and pyriform sinus (tdilute barium=21.01, tthick barium=19.85), the duration of pharynx period (tdilute barium=17.03, tthick barium=13.68), and the start time of pharynx period (tdilute barium=19.63, tthick barium=17.86) were less in the treatment group than in the control group (P0.05). Conclusion Acupuncture combined doctor-nurse cooperation mode may decrease the rates of aspiration and stroke-associated pneumonia in acute stroke patients through improving their swallow function.