Abstract
Purpose To examine the characteristics of adjacent vertebral fractures (AVF) following balloon kyphoplasty (BKP) in patients with previous adjacent vertebral fractures and assess whether these previous fractures exert a suppressive effect on AVF development subsequent to BKP. Methods One hundred and thirty-three patients who underwent BKP were enrolled. 32 patients had experienced previous adjacent vertebral fractures (Group P), while 101 patients served as the control group with no previous adjacent vertebral fractures (Group C). Clinical parameters were compared between Group P and Group C. AVF incidence was investigated, and Hounsfield unit (HU) values in the adjacent vertebral bodies were assessed. Additionally, the P group was divided into two subgroups based on the presence or absence of AVF. Clinical parameters and the difference in the HU values of the adjacent vertebral bodies above and below were compared between the two subgroups. Results In the comparison of Group P and Group C, there was no significant difference in AVF incidence (10/29 (34.5%) vs. 24/101 (23.8%), P=0.337). Conversely, the young adult mean (YAM) was found to be significantly lower (62.1±11.1% vs. 72.0±7.5%, P<0.001*), and the number of previous fractures significantly higher (2.2±1.3 vs. 0.5±0.7, P<0.001*) in Group P. In Group P, AVF occurred in 10 of 29 patients, including one case of re-fracture of a previously fractured adjacent vertebral body and nine cases of fracture in a contralateral adjacent vertebral body without previous fracture. In the comparison of previously fractured adjacent vertebral bodies and contralateral adjacent vertebral bodies in Group P, the AVF incidence was significantly lower (1/29 (3.4%) vs. 9/29 (31.0%), p=0.012*), and the HU value was significantly higher (158.6±62.6 vs. 69.6±23.0, P<0.001*) in previously fractured adjacent vertebral bodies. In the comparison between AVF (+) and AVF (-) in Group P, a significant difference was observed in the HU value difference of the adjacent vertebral bodies above and below (AVF (+): 118.7±67.0 vs. AVF (-): 72.7±53.6, P=0.046*). Conclusion Previous adjacent vertebral fractures do not suppress AVF occurrence. AVF is less likely to occur in vertebral bodies with previous fractures due to bone sclerosis, but it is more common in the contralateral adjacent vertebral bodies due to bone fragility. In cases with previous fractures in the adjacent vertebral bodies, patients exhibiting a large difference in the HU values of the adjacent vertebral bodies above and below are more likely to develop AVF.