Analysis of influencing factors for "shell" phenomenon in centrum after thoracolumbar fracture reduction

English Keywords:Thoracolumbar fractures  "Shell" phenomenon  Influencing factor

English Abstract:

  【Abstract】 Objectives: To investigate the influencing factors for the "shell" phenomenon after thoracolumbar fracture reduction. Methods: A retrospective analysis was conducted in 116 patients with single-segment thoracolumbar fracture who received posterior pedicle screw reduction and internal fixation in our department from January 2013 to December 2015. Their detailed information was recorded, including age, gender, course of disease, degree of preoperative spinal compression, preoperative sagittal Cobb angle, fracture type, bone density, screw placement in diseased spinal segment, distraction and reduction of fracture, degree of reduction, and screw position. The incidence of the "shell" phenomenon was observed. Single-factor analysis and multiple-factor logistic regression analysis were used to study the correlation between these factors and the incidence of the "shell" phenomenon. Results: The "shell" phenomenon in centrum occurred in the 72 of 116 patients, with an incidence of 62.1%. Single-factor analysis showed that the "shell" phenomenon was significantly correlated with distraction and reduction of fracture, degree of reduction, degree of preoperative spinal compression, and bone density(P<0.05), but not related to age, gender, course of disease, fracture type, preoperative sagittal Cobb angle, screw setting in diseased spinal segment, and screw position(P>0.05). Multiple-factor Logistic regression analysis showed that bone density and degree of preoperative spinal compression were major risk factors for "shell" phenomenon. Conclusions: The "shell" phenomenon after thoracolumbar fracture reduction is influenced by many factors, the degree of preoperative vertebral compression and bone density may be the major risk factors of the problem.