Relationship of Preexisting Vertebral Fractures and Endplate Injury to Intervertebral Bridging Ossification After Balloon Kyphoplasty for Osteoporotic Vertebral Fractures.

INTRODUCTION

Intervertebral bridging ossification (IBO) occasionally occurs after balloon kyphoplasty (BKP) for osteoporotic vertebral fractures (OVFs), contributing to stabilization. However, the predisposing factors remain unclear. This study aimed to identify preoperative factors associated with IBO formation.

METHODS

This was a retrospective cohort study of patients who underwent BKP for OVFs. Radiological evaluations included the location of the fractured vertebra, number of preexisting vertebral fractures, endplate damage, intervertebral disc injury, presence of diffuse idiopathic skeletal hyperostosis, lateral wedge angle and regional kyphosis angle, and were assessed using radiography, computed tomography and magnetic resonance imaging (MRI). Clinical outcomes were evaluated via the visual analogue scale (VAS) and Oswestry Disability Index (ODI) preoperatively and at 1 month and 1 year postoperatively.

RESULTS

Patients with IBO showed higher rates of thoracolumbar junction fractures (T11-L1) (p < 0.001), more preexisting vertebral fractures (p < 0.001), proximal endplate injury (p < 0.001), increased T2-weighted signal intensity of the adjacent intervertebral disc (p = 0.015) and larger lateral wedge angles in supine (p = 0.008) and sitting positions (p = 0.001). At 1 month, VAS scores were higher in the IBO group (4.2 ± 1.8 vs. 2.6 ± 2.0, p = 0.001). Multiple regression analysis revealed preexisting vertebral fractures (p < 0.001) and proximal endplate injury (p = 0.002) as independent predictors of IBO formation. VAS scores at 1 month postoperatively were worse in the IBO group (p = 0.001), but no significant differences were observed at 1 year.

CONCLUSION

Preexisting vertebral fractures and proximal endplate injury are key predictors of IBO formation after BKP. Although associated with higher short-term pain, IBO appears to contribute to long-term stabilization and pain relief, providing insights into postoperative outcomes and treatment strategies.