Biomechanical and biocompatible enhancement of reinforced calcium phosphate cement via RGD peptide grafted chitosan nanofibers / 浙江大学学报·医学版

Objective: To analysis the biomechanical and biocompatible properties of calcium phosphate cement (CPC) enhanced by chitosan short nanofibers(CSNF) and Arg-Gly-Asp (RGD). Methods: Chitosan nanofibers were prepared by electrospinning, and cut into short fibers by high speed dispersion. CPC with calcium phosphorus ratio of 1.5:1 was prepared by Biocement D method. The composition and structure of CPC, CSNF, RGD modified CSNF (CSNF-RGD), CSNF enhanced CPC (CPC-CSNF), RGD modified CPC-CSNF (CPC-CSNF-RGD) were observed by infrared spectrum, X-ray diffraction (XRD) and scan electron microscopy (SEM). The mechanical properties were measured by universal mechanical testing instrument. The adhesion and proliferation of MC3T3 cells were assessed using immunofluorescence staining and MTT method. Results: The distribution of CSNF in the scaffold was homogeneous, and the porous structure between the nanofibers was observed by SEM. The infrared spectrum showed the characteristic peaks at 1633 nm and 1585 nm, indicating that RGD was successfully grafted on chitosan nanofibers. The XRD pattern showed that the bone cement had a certain curability. The stain-stress test showed that break strengths were (17.74±0.54) MPa for CPC-CSNF and (16.67±0.56) MPa for CPCP-CSNF-RGD, both were higher than that of CPC(all PPConclusion: CSNF-RGD can improve the biomechanical property and biocompatibility of CPC, indicating its potential application in bone tissue repair.

Single use of transarticular screws in atlantoaxial instability / 中华骨科杂志

Objective To research the biomechanical characteristics and clinical applicant of posterior transarticular screws (Magerl technique) with bene graft in atlantoaxial instability.Methods 30 fresh cadaver human cervical spine specimens were obtained and randomized subdivided into 5 groups:intact group,atlantoaxial destabilized group,atlantoaxial destabilized and fixed with pedicle screws group,fixed with Magerl screws group and fixed with Maged screws combined with Brooks way group.ROM(range of motion)and NZ(neutral zone)of extend,flex,right and left lateral bend,right and left rotation of each specimen in 5 groups were measured.Transarticular screws were placed in 23 patients with atlantoaxial instability from 2000 Feb.to 2005 Jan.,with 16 males and 7 females,age from 17 to 62 years.20 of them were traumatic dislocation and 3 were congenital instable.Results Biomechanical study indicated that stability of all 6 degrees were Magerl+Brooks＞Magerl screws＞Pedicle screws＞Intact＞Destabilized.23 patient were fixed with 46 Maged screws in total,none were suffered from vertebral artery injury and neurological deterioration.All patients were followed-up from 4 to 36 months.2 of them complained that difficult in rotation of head.Conclusion Single use of Magerl screw can provide enough biomechanical stable for adantoaxial instability,and is an effective,low-risky way combined with intra-spinal-process bone graft.