Relationship Between Clinical Factors And The Absorption Of The Bone Fragment In Thoracolumbar Burst Fractures After Surgery

Objective: 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 who without spinal cord or nerve damage after thoracolumbar burst fractures were included in.We evaluated 3D-computed tomography scans for these patients before surgery,within a week after surgery,and 6 months after surgery.We calculated the volume of the bone fragment by these 3D-CT images.The reduction rate was defined as the difference between the measured volume of the canal that was encroached by bone fragments preoperatively and within 3 days postoperatively as a percentage.The resorption rate was defined as the difference between the measured volume of the canal encroached by bone fragments postoperatively and 6 months postoperatively and was expressed as a percentage.Factors potentially affecting the postoperative degree of reduction and spontaneous spinal remodeling were defined as age,sex,location,degree of change of anterior vertebral compression ratio,different implantation of the pedicle screw,recovery rate of Cobb angle.Multiple regression analyses were conducted on these factors to analyze the extent of their influence on the reduction and resorption rates.Results: The reduction rate and resorption rate have no correlation with age,sex,location,different implantation of the pedicle screw,recovery rate of Cobb angle(P>0.05).The recovery rate of the anterior compression is 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 has been restored,0.429% of the reduction rate increases,0.284% of the resorption rate increases.Conclusion: 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,we must pay more attention to the distraction technique during the operation so as to get better recovery of the anterior compression.