The purpose of this study is to determine the ideal period of brace application for thoracolumbar (T10-L2) osteoporotic vertebral compression fracture (OVCF) based on the progression of the vertebral compression with passage of time and to evaluate the factors associated with progression of thoracolumbar OVCF, when treated conservatively.

This retrospective study included a total of 46 patients who were diagnosed with thoracolumbar OVCF and could be followed-up for at least 6 months. In this study, the increase of compression rate and the mean slope of compression rate per weeks were compared between two periods (from diagnosed date to 8 weeks and from 8 weeks to 6 months), as the standard point. Age, bone mineral density (BMD), osteoporosis treatment after injury, diabetes mellitus (DM) as underlying disease were also compared between two groups (setting up 15% as standard point of increase of compression rate, <15% and ≥15%). Statistical analyses were performed using the paired t-test to assess the increase of compression rate and using the linear mixed model to assess the mean slope change. The relationships between the factors and progression of compression were analyzed using t-test, chi-square test, and logistic regression analysis.

The increase of compression rate was 13.03% and 1.97% in each period and the difference between those two periods was 11.06% (p=0.00). At 8 weeks of follow-up, the mean slope was reduced by 1.12 (p=0.00). No statistically significant difference in related factors was observed between two groups.

Considering the increase of compression rate with passage of time, brace should be applied strictly for an initial 8 weeks. And age, BMD, osteoporosis treatment after injury, and DM as underlying disease are not predictors of progression of compression in vertebral fractures.