Relationship between clinical factors and the absorption of the bone fragment in thoracolumbar burst fractures after surgery

English Keywords:Thoracolumbar burst fractures  Spontaneous spinal remodeling  Reduction rate  Resorption rate

English Abstract:

  【Abstract】 Objectives: To analyze the relationship between clinical factors and the absorption of the bone fragment after posterior distraction and indirect decompression of thoracolumbar burst fractures. Methods: 61 patients without spinal cord nerve damage after thoracolumbar burst fractures were included. 3D-computed tomography scan was performed on these patients before surgery, within a week after surgery, and at 6 months after surgery. The volume of the bone fragment was calculated by 3D-CT images. The ratio of the volume of bone fragments at 3 days after operation to those before the operation was called reduction rate. The ratio of the volume of bone fragments at 6 months after operation to those immediately after the operation was called reabsorption rate. Factors potentially affecting the postoperative degree of reduction and spontaneous spinal remodeling, including age, sex, location, degree of change of anterior vertebral compression ratio, different implantations of the pedicle screws, and recovery rate of Cobb angle were analyzed. Multiple regression analyses were conducted on these factors to analyze the extent of their influences on the reduction and resorption rates. Results: The reduction rate and resorption rate had no correlation with age, sex, location, different implantations of the pedicle screws, recovery rate of Cobb angle(P＞0.05). The recovery rate of the anterior compression was significantly related(P＜0.05) to the reduction rate(t=3.552) and the resorption rate(t=2.262) after surgery. When 1% of the anterior compression rate had been restored, 0.429% of the reduction rate increased, 0.284% of the resorption rate increased. Conclusions: During posterior distraction and indirect decompression, the recovery rate of the anterior compression is significantly related to the bone fragment absorption and spontaneous canal remodeling. Therefore, more attention must be paid to the distraction technique during the operation so as to get better recovery of the anterior compression.