Vertebral balloon kyphoplasty versus vertebral body stenting in non-osteoporotic vertebral compression fractures at the thoracolumbar junction: a comparative radiological study and finite element analysis (BONEXP study)

Objective To compare radiologically balloon kyphoplasty (BKP) and vertebral compression fracture (VCF) expansion and corroborate with a finite element (FE) analysis. The principle of BKP is to stabilize VCF by restoring vertebral body anatomy using bone expansion and cement filling. More recently, vertebral body stenting (VBS) has been developed to reduce the loss of vertebral height observed after balloon deflation. Methods A retrospective, monocentric and continuous study of 60 non-osteoporotic fractures of the thoracolumbar junction treated by vertebral bone expansion was carried out over three years. The main endpoint was radiological correction of vertebral kyphosis (VK) at 3 months. The other studied parameters were vertebral height, index of Farcy, index of Beck, cement leakages and their location. A FE model was developed to analyze effects linked to the stent during cement injection, specifically throughout the risk of cement leakage evaluation. Results After three months, average reduction of VK was 4.73° ± 4.8° after BKP, and 4.63° ± 2.7° after VBS. There was no difference between the two techniques, but cement leakage was significantly greater with BKP (41.7%) than with VBS (4.2%). FE analysis showed substantial changes of the cement flow orientation in the presence of a stent. Conclusion BKP and VBS offer comparable expansion with no added value of VBS in non-osteoporotic VCF reduction. VBS technique appears to prevent cement leakage due to its mesh architecture hindering the leaking process. In counterpart, such balloon expansion is likely to require higher pressure to deploy the stent. This could be an important parameter to take into account in young patients with high bone density.