Evaluation of relation between length of pedicular screw to AP length of vertebrae ratio with fusion in patients with operated thoracolumbar fracture

Abstract

A large proportion of vertebral fractures occur in the thoracolumbar region. The purpose of treating sciatica in this area is to create a solid bed to prevent nerve damage and increase deformity and finally to fix the broken spine for the next fusion. Therefore, the aim of this study was to compare the ratio of screw length to posterior anterior vertebral length with fusion rate in patients with thoracolumbar vertebral fracture in patients with fractures in this area. Materials and methods: This study was retrospective and was performed on 80 patients with fractures of the thoracolumbar spine from 2016 to 2018 who were in Imam Reza Hospital in Tabriz and Shohada in Tabriz under posterolateral fusion with pedicular screw and rod placement. The anteroposterior length of vertebral body and the length of the screw used were measured and then the ratio of these two factors was determined. Patients were divided on the basis that the pedicle screws were less than 50%, between 50% and 75%, and more than 75% of the anteroposterior length of the vertebra. Then the amount of vertebral fusion and F angle in 6-month follow-up were studied in the study groups. The results were analyzed by SPSS software (ver.21). Results: The mean age of patients in the study was 37.24±11.73years. The most common fracture was T12 with 40%. The most common mechanism of vertebral fracture was car accidents with 49%. The vertebral fusion rate was 83% and 13 patients don’t have fusion. The F-angle in patients before surgery was 23.64±3.78 which decreased to 12.49±1.4 after surgery, and this decrease was also statistically significant (P <0.001). There was a significant difference between the groups in terms of vertebral fusion rate. x² = 4.733 and P = 0.03. F-Angle in the group of screw-to-body length ratio of more than 75% was 11.86 ± 1.32 and in the group of screw-to-body length ratio of less than 50% was 14.41±1.44 degrees, which was statistically significant. P value = 0.045