All levels miniplate fixation and a modified hybrid fixation method in expansive open-door cervical laminoplasty: a retrospective comparative study / 北京大学学报(医学版)

OBJECTIVE@#To retrospectively compare the effect of alternate levels miniplate and anchor fixation with the effect of all levels miniplate fixation in expansive open-door cervical laminoplasty (EOLP).@*METHODS@#Patients with cervical spondylosis underwent EOLP between July 2015 and June 2016 were included in the study. There were 33 patients in the alternate group (alternate levels miniplate and anchor fixation group) and 34 patients in the miniplate group (all levels miniplate fixation group). Neurological function was evaluated with the Japanese Orthopedic Association (JOA) score and degree of pain was assessed with the visual analogue scale (VAS) score. Basic clinical and surgical data, complication rates and medical costs of the two groups were compared. In addition, radiological examinations were performed pre- and post-operatively and at the final follow-up. Relative imaging data such as anteroposterior diameter (APD), cervical curvature index (CCI) and open angle were collected and compared.@*RESULTS@#(1) The mean follow-up time was 18.6 months in the alternate group and 18.9 months in the miniplate group. There were no significant differences in operation time, intraoperative blood loss, perioperative complication rates, post-operative hospital stays, VAS scores and neurological recovery rates preoperatively and at the final follow-up between the two groups. (2) Additionally, no obvious differences were observed about CCIs and APDs at the three follow-up time points between the two groups. Post-operative open angles at C4 and C6 in the alternate group were significantly smaller than those in the miniplate group. However, there were no significant differences in C3, C5 and C7 open angles between the two groups post-operatively. Notably, no significant differences were detected about the open angles at all levels between the two groups at the final follow-up. (3) When comparing radiologic data at different time points in each group, CCIs and open angles at each level had no significant differences, but APDs after surgery and at the final follow-up were significantly larger than pre-operative APDs. (4) Total costs in the alternate group were significantly lower than those in the miniplate group.@*CONCLUSION@#The two surgical methods showed almost the same neurological recovery rates and complication rates. However, use of alternate levels miniplate and anchor fixation in EOLP can reduce medical expenses.

Osteogenic differentiation of bone mesenchymal stem cells regulated by osteoblasts under EMF exposure in a co-culture system / 华中科技大学学报（医学）（英德文版）

This study examined the osteogenic effect of electromagnetic fields (EMF) under the simulated in vivo conditions. Rat bone marrow mesenchymal stem cells (BMSCs) and rat osteoblasts were co-cultured and exposed to 50 Hz, 1.0 mT EMF for different terms. Unexposed single-cultured BMSCs and osteoblasts were set as controls. Cell proliferation features of single-cultured BMSCs and osteoblasts were studied by using a cell counting kit (CCK-8). For the co-culture system, cells in each group were randomly chosen for alkaline phosphatase (ALP) staining on the day 7. When EMF exposure lasted for 14 days, dishes in each group were randomly chosen for total RNA extraction and von Kossa staining. The mRNA expression of osteogenic markers was detected by using real-time PCR. Our study showed that short-term EMF exposure (2 h/day) could obviously promote proliferation of BMSCs and osteoblasts, while long-term EMF (8 h/day) could promote osteogenic differentiation significantly under co-cultured conditions. Under EMF exposure, osteogenesis-related mRNA expression changed obviously in co-cultured and single-cultured cells. It was noteworthy that most osteogenic indices in osteoblasts were increased markedly after co-culture except Bmp2, which was increased gradually when cells were exposed to EMF. Compared to other indices, the expression of Bmp2 in BMSCs was increased sharply in both single-cultured and co-cultured groups when they were exposed to EMF. The mRNA expression of Bmp2 in BMSCs was approximately four times higher in 8-h EMF group than that in the unexposed group. Our results suggest that Bmp2-mediated cellular interaction induced by EMF exposure might play an important role in the osteogenic differentiation of BMSCs.

Osteogenic differentiation of bone mesenchymal stem cells regulated by osteoblasts under EMF exposure in a co-culture system / 华中科技大学学报（医学）（英德文版）

This study examined the osteogenic effect of electromagnetic fields (EMF) under the simulated in vivo conditions. Rat bone marrow mesenchymal stem cells (BMSCs) and rat osteoblasts were co-cultured and exposed to 50 Hz, 1.0 mT EMF for different terms. Unexposed single-cultured BMSCs and osteoblasts were set as controls. Cell proliferation features of single-cultured BMSCs and osteoblasts were studied by using a cell counting kit (CCK-8). For the co-culture system, cells in each group were randomly chosen for alkaline phosphatase (ALP) staining on the day 7. When EMF exposure lasted for 14 days, dishes in each group were randomly chosen for total RNA extraction and von Kossa staining. The mRNA expression of osteogenic markers was detected by using real-time PCR. Our study showed that short-term EMF exposure (2 h/day) could obviously promote proliferation of BMSCs and osteoblasts, while long-term EMF (8 h/day) could promote osteogenic differentiation significantly under co-cultured conditions. Under EMF exposure, osteogenesis-related mRNA expression changed obviously in co-cultured and single-cultured cells. It was noteworthy that most osteogenic indices in osteoblasts were increased markedly after co-culture except Bmp2, which was increased gradually when cells were exposed to EMF. Compared to other indices, the expression of Bmp2 in BMSCs was increased sharply in both single-cultured and co-cultured groups when they were exposed to EMF. The mRNA expression of Bmp2 in BMSCs was approximately four times higher in 8-h EMF group than that in the unexposed group. Our results suggest that Bmp2-mediated cellular interaction induced by EMF exposure might play an important role in the osteogenic differentiation of BMSCs.