Association between final local kyphosis angle and residual back pain in traumatic vertebral fractures at the thoracolumbar junction with posterior stabilization using percutaneous pedicle screws.

Background: There is no consensus on the association between final local kyphosis and residual back pain (RBP) after traumatic vertebral fracture. The aim of this study was to investigate whether there is an association between the final local kyphosis angle and RBP in patients with traumatic vertebral fractures at the thoracolumbar junction who underwent single posterior surgery with percutaneous pedicle screws and implant removal after fracture healing. A second goal was to determine the optimal cut-off value for the final local kyphosis angle with and without RBP.

Methods: Twenty-five patients were included in the study. Age, gender, Injury severity score, level of fracture, AO classification, the McCormack Load sharing classification, and range of stabilization were collected. In addition, imaging assessment was performed to evaluate vertebral kyphosis angle, local kyphosis angle (Cobb angle), and the percentage of anterior, middle and posterior vertebral body compression at the time of injury and at the final follow-up after implant removal. The patients were divided into two groups, with and without RBP [Group RBP (+) and Group RBP (-), respectively]. Each variable was compared between groups. Cut-off values were calculated using the Youden index with receiver operating characteristic (ROC) curves.

Results: There were 12 patients in the RBP (+) group and 13 in the RBP (-) group. The two groups were significantly different only for the final local kyphosis angle, with no significant differences for the other variables. The ROC curve of the final local kyphosis angle for RBP had an area under the curve (AUC) of 0.88 (P<0.01). The optimal cut-off value for the final local kyphosis angle for RBP calculated from the Youden index was 15.85°.

Conclusions: There is an association between the final local kyphosis angle and RBP. The optimal cut-off value of the final local kyphosis angle for RBP was approximately 16°.