Abstract:

BACKGROUND: In the animal model of spinal cord injury associated with fractures, the trauma is severe and postoperative survival rate is low. The improved Allen method and open femoral osteotomy method for making animal model has many advantages, such as simple operation, no need of special equipment, quick establishment, shortened operation time and reduced intraoperative bleeding, so they are suitable for preparing a femoral fracture model combined with spinal cord injury.
OBJECTIVE: To design an animal model of femoral fracture combined with spinal cord injury, which can maintain long time survival, meet clinical features, and is simple and easy.
METHODS: Forty-eight male Sprague-Dawley rats were randomly divided into simple femoral fracture group and femoral fracture merging spinal cord injury group. Femoral fracture model was caused by opening osteotomy to cause transverse fracture and implantation of internal fixator in femur. According to the improved Allen method, a self-made blow device was applied to cause acute T10 segment contusion injury of spinal cord in rats. Thus the femoral fracture model merging spinal cord injury was successfully established. The rats in two groups were grossly observed at different time points after the modeling, and the fracture healing at 4 weeks was detected.
RESULTS AND CONCLUSION: All the animal models of femoral fracture with spinal cord injury survived, which exhibited the loss of sensory and motor function of the lower limbs, but could slowly creep forward by the upper limbs. In the first 3 days, the rats had poor appetite and few activity, with tail suspension at night there were no ischemia and necrosis of the limb fracture. At 4 weeks, one rat in simple femoral fracture group died, while four rats in femoral fracture merging spinal cord injury group died, with the survival rate of 83.33%, intramedullary fixation were not prolapsed. In the two groups, continuous bone callus formation was found in the fracture, and the bone callus volume in femoral fracture merging spinal cord injury group was significantly higher than those in simple femoral fracture group. The results demonstrated that combining the improved Allen method with small lateral incision open femoral osteotomy is a simple and feasible method for the establishment of femoral fracture model merging spinal cord injury, and the models survive for 4 weeks.

Key words: femoral fractures, spinal cord injuries, models, animal, postoperative complications, osteotomy