Effects Of CMF And Porous BCP Intervention On The Posterolateral Lumbar Fusion In Rabbits

Objective To explore effects of the CMF for the fusion and new bone-formation, by the combined magnetic fields (CMF) and porous Biphasic Calcium Phosphate (BCP) treatment on the rabbit spinal fusion model of posterolateral lumbar fusion.Methods32adult rabbits underwent surgical preparation of the bilateral Intetransverse Process Fusion at the5th to6th lumbar vertebra level. Animals were randomly divided into four groups including G1, G2, G3and G4groups. Rabbits in G1were subjected to autologous iliac bone graft (AIBG) and CMF treatment, and G2with BCP+CMF treatment, and G3with AIBG+conciliative CMF treatment, and G4with BCP+conciliative CMF treatment. CMF treatment was performed once a day for8weeks post-surgery. The samples were separated from the animal body at9weeks after surgery, followed by high-resolution CT scanning for the evaluations of the spinal fusion, new bone-formation and residual BCP, as well as histological examination by HE staining.Results (1) The spinal integration rate in group G1was significantly higher than that of group G2, G3and G4(P<0.05), and the group G2and G3higher than group G4(P<0.05), Factorial analysis demonstrated that the CMF treatment significantly improved the spinal integration rate (P<0.05).(2)The gray value of bone in group G1was significantly higher than that of the group G3(P<0.05), but no statistical difference between group G2and G4(P>0.05), and CMF treatment group compared with placebo group has no significant difference (P>0.05).(3) New bone formation was evaluated by bone volume and surface area, which in group G1were higher than the group G3(P<0.05), and that in group G2higher than group G4(P<0.05). CMF treatment significantly increased the new bone volume and surface area (P<0.05).(4) There was no significantly statistical difference of bone volume and surface area of residual BCP between group G2and group G4(P>0.05).(5) The results indicated that the spinal fusion score in group G1was significantly higher than the other groups (P<0.05), but no difference among the groups G2, G3and G4(P>0.05). Factorial analysis implied CMF treatment significantly improved the spinal fusion outcome (P<0.05).(6) spinal fusion rate in the group G1was significantly higher than the group G4(P<0.05), there are no significant difference among the other groups (P>0.05). CMF treatment group significantly improved the spinal fusion rate (P<0.05).(7) The number of bone cells in group G1was significantly higher than that in group G3(P<0.05), as well as that in group G2when comparing with group G4(P <0.05), CMF treatment was significantly promoted the number of bone cells (P<0.05).(8) The percentage of new bone area of group G1was significantly higher than that of group G3(P<0.05), and group G2higher than group G4(P<0.05). CMF treatment was significantly increased the new bone formation (P<0.05)Conclusions (1) CMF treatment significantly improved spinal fusion and new bone-formation of autologous iliac bone graft in the rabbit model of PLF.(2) CMF treatment can significantly improve spinal fusion and new bone-formation of porous BCP in the rabbit model of PLF.(3) CMF had the potential to be served as a safe and effective adjuvant strategy for therapy of spinal fusion.(4) CMF combined with porous BCP for clinically surgical therapy of spinal fusion provides a new ideal.