Research on pharyngeal bacterial flora in transoral atlantoaxial operation and the postoperative follow-up study.

OBJECTIVES: To study the changes of bacterial flora after a series of preoperative oral disinfection and the postoperative recovery of nerve function of patients with craniovertebral junction disorders who were treated with transoral approach operations. METHODS: This research analyzed 20 cases collected from October 2009 to May 2010. All these patients were with CVJ disorders, including 8 males and 12 females, aged 2 to 66 (38.1 on average), and they were all treated with transoral approach operations. The mucosa samples of the posterior pharyngeal wall were sent for bacteria culture. These samples were collected by sterile cotton swabs at four crucial points, including 3 days before operation/before gargling, 3 days after continuous gargling/after anesthesia intubation on the day of operation, after intraoperative cleaning and washing of the mouth, and after intraoperative iodophor immersion. The microflora was stained by means of smear and further counted after an investigation by microscope. The neural function of patients was evaluated by the ASIA classification and the JOA scores. All patients but two with posterior stabilization performed respectively underwent transoral atlantoaxial reduction plate (TARP) fixation consecutively in the same sitting. A regular reexamination of cervical vertebra with lateral and open mouth X-ray, CT and MRI was conducted after operation to evaluate the reduction of atlantoaxial dislocation, internal fixation position, bone graft fusion, inflammatory lesions and tumor recurrence. RESULTS: This bacteriological research showed that the mucosa of the posterior pharyngeal wall of all the patients was in a sterile state after a series of oral preoperative preparations and intraoperative iodophor disinfection, which was considered as type I incision. The bacterial culture results of the mucosa samples of the posterior pharyngeal wall collected at different time points showed significant differences (χ2 = 42.762, P = 0.000). All the patients had improvement in ASIA, and their neural functions were improved to different levels after operation. There was a significant difference in JOA scores before and after operation (t = 8.677, P = 0.000). Postoperative imaging examination showed that the atlantoaxial screw position was good and firm, and the CVJ disorders were treated appropriately. CONCLUSION: It is safe and effective to cut the posterior pharyngeal muscle layer and implant internal fixation by means of transoral approach.

Characterization and cytocompatibility of 3D porous biomimetic scaffold derived from rabbit nucleus pulposus tissue in vitro.

Intervertebral disc (IVD) degeneration is one of the most important causes of lower back pain. Tissue engineering provides a new method for the experimental treatment of degenerative disc diseases. This study aims to develop a natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus. The nucleus pulposus (NP) was decellularized by sequential detergent-nuclease methods, including physical crushing, freeze-drying and cross-linking. These 3D porous scaffolds were fabricated with a high porosity of (81.28 ± 4.10)%, an ideal pore size with appropriate mechanical properties. Rabbit bone marrow mesenchymal stem cells (rBMSCs) were seeded and cultured on the scaffolds. And the mechanical tests showed the compressive elastic modulus of the scaffolds cultured for 4 weeks reached 0.12 MPa, which was better than that of the scaffolds cultured for 2 weeks (0.07 MPa) and that of the control group (0.04 MPa). Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration and secretion of seeded cells in vitro. As assays like histology, immunohistochemistry and the real-time qRT-PCR showed, NP-like tissues were preliminarily formed. In conclusion, the 3D porous scaffold derived from NP ECM is a potential biomaterial for the regeneration of NP tissues. A natural, acellular, 3D interconnected porous scaffold derived from the extracellular matrix (ECM) of nucleus pulposus was developed by sequential detergent-nuclease and freeze-drying method, which can reduce the damage of protein activity to the minimum. It is very similar to the composition and internal environment of the natural nucleus pulposus, because it derived from the natural nucleus pulposus. Scanning electron microscopy (SEM), histological assays, molecular biology assays revealed that the scaffolds could provide an appropriate microstructure and environment for the adhesion, proliferation, migration, and secretion of seeded cells in vitro.

Osteogenic activity of silver-loaded coral hydroxyapatite and its investigation in vivo.

In this study, the scaffolds based on mineralized silver-loaded coral hydroxyapatites (SLCHAs) were developed for bone regeneration in the radius of rabbit with a 15-mm infective segmental defect model for the first time. The SLCHAs were achieved by surface adsorption and ion-exchange reaction between Ca(2+) of coral hydroxyapatite (CHA) and Ag(+) of silver nitrate with different concentration at room temperature. Release experiment in vitro, X-ray diffraction and scanning electron microscopy equipped with energy-dispersive X-ray spectrometer were applied to exhibit that the scaffold showed some features of natural bone both in main component and hierarchical microstructure. The three-dimensional porous scaffold materials imitate the microstructure of cancellous bone. Mouse embryonic pre-osteoblast cells (MC3T3-E1) were used to investigate the cytocompatibility of SLCHAs, CHA and pure coral. Cell activity were studied with alkaline phosphataseenzyme assay after 2, 4, 6 days of incubation. It was no statistically significant differences in cell activity on the scaffolds of Ag(+)(13.6 µg/mL)/CHA, Ag(+)(1.7 µg/mL)/CHA, CHA and pure coral. The results indicated that the lower silver concentration has little effect on cell activity. In the implantation test, the infective segmental defect repaired with SLCHAs was healed up after 10 weeks after surgery, and the implanted composites were almost substituted by new bone tissue, which were very comparable with the scaffold based on mineralized CHA. It could be concluded that the SLCHAs contained with appropriate silver ionic content could act as biocidal agents and maintain the advantages of mineralized CHA or coral, while avoiding potential bacteria-dangers and toxical heavy-metal reaction. All the above results showed that the SLCHAs with anti-infective would be as a promising scaffold material, which whould be widely applied into the clinical for bone regeneration.

[In vitro drug release from a mitomycin C delivery system and its effect against scar tissue adhesion in vivo].

OBJECTIVE: To develop a chitosan (CH)/polyethylene glycols succinate acid (PEG-SA)-mediated mitomycin C (MMC) delivery system and investigate its drug release characteristics in vitro and its effect against scar tissue adhesion in vivo. METHODS: Mitomycin C loading in the composite CH/PEG-SA/MMC films was determined using ultraviolet. The freeze-dried films were dispersed in 1 ml PBS (pH7.4) and mitomycin C release in vitro was determined according to the mitomycin C concentration-UV value standard curve. The influence of the film structure on the drug release was evaluated. The drug delivery system was then implanted in SD rats, and 4 weeks later, immunohistochemical and histological examinations were carried out to assess the therapeutic effect on epidural scar tissue. RESULTS: The linear regression equation of the mitomycin C concentration-UV value standard curve was y=0.593x(3)-2.563x(2)+25.944x-0.236 (R(2)=1.000). The film demonstrated good drug delivery capability, and 20 mg of the samples in PBS showed a peak mitomycin C release after 12 days of 14.9616 microg/ml, which was higher than the ID(50) of mitomycin C (10.4713 microg/l) to the fibroblasts. On days 18 and 32, another two drug release peaks occurred (14.4824 microg/ml and 11.4092 microg/ml, respectively), followed by maintenance of slow release. Till day 60, the accumulative mitomycin release reached 0.1793 microg/ml, and the loaded drug was ultimately completely released. Significant differences were noted in the hydroxyproline content in the scar tissues of different groups (F=12.085, P=0.000), and the CH/PEG-SA/MMC DDS reduced the amount of scar tissue and promoted its orderly alignment to control potential scar hyperplasia that may compress the spinal cord and nerve roots. CONCLUSION: The composite film for drug delivery possesses good flexibility and mechanical properties and allows sustained drug release of mitomycin C to prevent epidural scar tissue adhesion following lumbar laminectomy.