Relationship between imaging parameters of type A3 thoracolumbar vertebral fracture with intra-canal invasion and reduction effect of posterior indirect decompression

English Keywords:Thoracolumbar vertebral fracture  Type A3 fracture  Indirect decompression  Imaging parameters

English Abstract:

  【Abstract】 Objectives: To analyze the imaging parameters of type A3 thoracolumbar vertebral fracture with intra-canal invasion, and to explore their relationships with the reduction effect of intra-canal fracture fragment after posterior indirect decompression. Methods: A retrospective study was conducted on 58 patients of type A3 thoracolumbar vertebral fracture with intra-canal invasion treated with posterior indirect decompression and internal fixation in our hospital from July 2020 to July 2022. According to the degree of reduction of intra-canal fracture fragment during surgery, the patients were divided into reduced group(45 cases) and unreduced group(13 cases). Hemilaminectomy and spinal canal decompression were also performed in the unreduced group. Parameters of fracture were compared between the two groups, including preoperative injured vertebrae compression ratio, intraoperative recovery degree of vertebral height, preoperative local kyphosis angle, preoperative location of intra-canal fracture fragment, preoperative inversion angle of intra-canal fracture fragment, preoperative rate of spinal canal invasion, preoperative ratio of height of bone fragments occupying the posterior wall of the injured vertebral body, preoperative ratio of the width of bone fragment occupying the transverse canal diameter, and postoperative neurological recovery. Multivariate logistic regression analysis of risk factors affecting the reduction of intraspinal fracture blocks was performed. Results: The injured vertebral compression ratio, local kyphosis angle, and spinal canal invasion rate before operation in the reduced group were lower than those in the unreduced group, respectively[(34.98±6.06)% vs (43.20±12.80)%, 20.64°±3.04° vs 24.80°±3.71°, (46.65±15.99)% vs (64.70±18.90)%], and the differences were statistically significant(P<0.05). The intraoperative recovery degree of vertebral height in the reduced group[(89.31±6.78)%] was bigger than that in the unreduced group[(65.87±4.67)%], with statistical significance(P<0.001). There were no significant differences between the two groups in inversion angle of intra-canal fracture fragment, location of intra-canal fracture fragment, ratio of height of bone fragments occupying the posterior wall of the injured vertebral body, ratio of the width of bone fragment occupying the transverse canal diameter, and postoperative neurological recovery(P>0.05). Multivariate logistic regression analysis showed that the preoperative injured vertebral compression ratio, kyphosis angle of the segment, spinal canal invasion rate, and intraoperative recovery degree of vertebral height were the risk factors affecting the reduction of intra-canal fracture fragment. Conclusions: The preoperative injured vertebral compression ratio, kyphosis angle of the segment, spinal canal invasion rate, and postoperative recovery degree of injured vertebral height are important parameters that influence the degree of reduction in type A3 thoracolumbar fracture with intra-canal fracture fragment after posterior indirect decompression.