Objective:To prepare a progressive gradient-aperture scaffold composed of silk fibroin(SF)-chitosan(CS)-nano-hydroxyapatite(nHAp)for osteochondral repair.Method:The SF solution, CS solution and nHA suspension were mixed in vitro at equal proportions.The progressive gradient osteochondral(OC)scaffold-1(2%), scaffold-2(3%)and scaffold-3(4%)was respectively prepared by using centrifugation, vacuum freeze-drying, chemical cross-linking and three shaping steps.General conditions, porosity, hot water dissolution rate, water swelling rate, compression water swelling rate, water swelling rate after dissolution, mechanical properties, internal structure observation and pore size were measured.Rat bone marrow mesenchymal stem cells(BMSCs)were cultured and the scaffold extract was prepared.The effect of scaffold extract on the proliferation of BMSCs was detected by the cell counting kit-8(CCK-8)method.BMSCs were co-cultured with the scaffold, and the distribution and morphology of the cells around the scaffold were observed.Results:The structure of scaffold was regular in each group and the porosity was more than 80%.Along with the increase of the material concentration, the water swelling rate of the scaffold was decreased gradually( P<0.05). Compared with before compression, the water swelling rate of scaffold-1 was decreased after compression( P<0.05). There was no significant difference in the hot water dissolution rate among all groups( all P>0.05), and the complete dissolution of the scaffold-1, scaffold-2 and scaffold-3 in vitro required 65.9, 60.9, and 73.9weeks, respectively.The elastic modulus of scaffolds in above three groups were 0.0955, 0.1762 and 0.3468 MPa, respectively.The examination results of scanning electron microscope(SEM)showed that the internal structure of scaffold was honeycomb in each group, the pore shape was regular, which showed an inter-connected pore network.The pore distribution was gradually dense and the pore diameter gradually decreased from the cartilage side to the osteogenic side( P<0.05), and the nHAp content increased gradually.The scaffold extract had no obvious toxicity to the growth and proliferation of BMSCs in each group.After BMSCs were seeded on scaffolds and co-cultured for 5 days, the cells grew well without obvious cell death or morphological abnormalities. Conclusions:In this study, a progressive gradient pore size OC scaffold is successfully prepared with good physical properties and biocompatibility, which is expected to be a new bio-mimetic composite scaffold material for repairing OC defects.

Objective:To investigate the clinical effects of anterior cervical discectomy and fusion combined with zero-profile anchored spacer (ROI-C) application on cervical spondylosis.Methods:Eighty-nine patients, consisting of 58 males and 31 females, who received anterior cervical discectomy and fusion combined with zero-profile anchored spacer (ROI-C) application in First People's Hospital of Guiyang from May 2015 to May 2018 were retrospectively analyzed. A total of 138 segments were fused. Operative time, intraoperative blood loss, postoperative complications and their incidence were recorded. The Japanese Orthopaedic Association score, Visual Analogue Scale score, and Neck Disability Index score were used to evaluate clinical effects of anterior cervical discectomy and fusion combined with ROI-C application. Imaging examination was performed to determine cervical curvature, intervertebral space height of fused segments, interbody fusion rate and changes in adjacent segments. The stability and long-term effects of postoperative cervical spine were evaluated.Results:All 89 patients were followed up for (25.6 ± 6.8) months (range 12-36 months). In 53 patients who underwent single-segment fusion, operative time was (85.54 ± 12.53) minutes and the amount of blood loss was (58.45 ± 10.24) mL. In 25 patients who underwent two-segment fusion, operative time was (115.57 ± 16.42) minutes and the amount of blood loss was (92.62 ± 12.44) mL. In 9 patients who underwent three-segment fusion, operative time was (148.63 ± 19.42) minutes and the amount of blood loss was (118.54 ± 11.25) mL. In 2 patients who underwent four-segment fusion, operative time and the amount of blood loss were 188 minutes and 175 mL, respectively in one patient and they were 214 minutes and 225 mL in another patient, respectively. With time went during 1 week to 12 months after surgery, Japanese Orthopaedic Association score was greatly increased, Neck Disability Index score was remarkably decreased, and Visual Analogue Scale score was also significantly decreased ( F = 11.25, 26.35, 20.26, all P < 0.05). Swallowing discomfort occurred in only 2 (2.2%) patients. No patients had incision hematoma, infection, hoarseness or choking cough. At 1 week to 12 months after surgery, cervical curvature and the height of intervertebral space of fused segments were superior to those before surgery (both P < 0.05). At 12 months after surgery, X-ray examination revealed bony fusion with no loosening and displacement of fusion cage and no obvious degeneration of adjacent segments. Conclusion:Anterior cervical discectomy and fusion combined with ROI-C application for the treatment of cervical spondylosis exhibits great therapeutic effects because it can greatly alleviate patient symptoms and improve cervical function.