Animal Modelling of Lumbar Corpectomy and Fusion and in vivo Growth of Spine Supporting Bone by Titanium Cage Implants: An Experimental Study

In this study a lumbar spinal fusion animal model is established to assess the effect of spinal fusion cage, and explore the minimum area ratio of titanium cage section to vertebral section that ensures bone healing and biomechanical property. Lumbar corpectomy was conducted by posterolateral approach with titanium cage implantation combined with plate fixation. Titanium cages with the same length but different diameters were used. After implantation of titanium cages, the progress of bone healing was observed and the bone biomechanical properties were measured, including deformation and displacement in axial compression, flexion, extension, and lateral bending motion. The factors affecting the in vivo growth of spine supporting body were analyzed. The results show that the area ratio of titanium cage section to vertebral section should reach 1/2 to ensure the bone healing, sufficient bone intensity and biomechanical properties. Some bone healing indicators, such as BMP, suggest that there is a relationship between the peak time and the peak value of bone formation and metabolism markers and the bone healing strength.