Prediction of Subsequent Vertebral Collapse after Osteoporotic Thoracolumbar Vertebral Fractures

Park, SeJun; Chung, SungSoo

Abstract

OBJECTIVES
To evaluate the clinical significance of vertebral bone bruise (VBB) in terms of subsequent collapse after osteoporotic thoracolumbar vertebral fractures.
METHODS
We reviewed 41 consecutive patients with 46 osteoporotic thoracolumbar vertebral fractures treated nonoperatively from March 2007 to February 2010. Anterior wedge angle (AWA) was measured on plain radiographs and the change of AWA between the initial and last measurement was used to represent the subsequent vertebral collapse. The size of VBB was measured and VBB ratio was calculated on T1-weighted sagittal MR image.
RESULTS
The average VBB ratio was 49.1% and the average change of AWA was 7.1degrees. Only VBB ratio significantly correlated with the change of AWA (P<0.001, cc=0.660). The other factors such as age, initial AWA, and endplate status showed no significant correlation with the change of AWA (P=0.629, P=0.724, P=0.690, respectively). In DEXA group, no correlation was found between T-score and the change of AWA as well as between T-score and VBB ratio (P=0.548, P=0.370, respectively). Five fractures were diagnosed as delayed post-traumatic vertebral collapse. Their average VBB ratio was 71.2% which was significantly higher than that of the other subjects (P=0.015). The fractures with VBB ratio more than 60% was likely to progress to delayed post-traumatic vertebral collapse.
CONCLUSIONS
VBB after osteoporotic thoracolumbar vertebral fracture was significantly correlated with subsequent vertebral collapse (cc=0.660). We recommend the patients with a large vertebral bone bruise, especially more than 60%, should be followed up meticulously for the early detection of delayed post-traumatic vertebral collapse.