CEMENT DISTRIBUTION AFFECTS LOAD-BEARING BY FRACTURED AND NEIGHBOURING VERTEBRAE FOLLOWING VERTEBROPLASTY

Introduction Vertebroplasty helps to restore mechanical function to a fractured vertebra. We investigated how the distribution of injected cement benefits both fractured and neighbouring vertebrae. Methods Nine pairs of three-vertebra cadaver spine specimens (aged 67–90 yr) were compressed to induce fracture. One of each pair underwent vertebroplasty with PMMA, the other with a resin (Cortoss). Specimens were then creep-loaded at 1.0kN for 1hr. Before and after vertebroplasty, compressive stiffness was determined, and stress profilometry was performed by pulling a pressure-transducer through each disc whilst under 1.0kN load. Profiles indicated intradiscal pressure (IDP) and compressive load-bearing by the neural arch (F N ) at both disc levels. Micro-CT was used to quantify cement fill in the anterior and posterior halves of each augmented vertebral body, and also in the region immediately adjacent to the fractured endplate Results Fracture reduced stiffness and IDP, and increased F N . Following vertebroplasty, anterior fill was greater for Cortoss (30%) than PMMA (17%) (P N in the non-adjacent disc (P Conclusion Cement distribution varied between the two cements. However, increased filling immediately adjacent to the fractured endplate was linked most consistently to improved mechanical function. Conflicts of Interest None Source of Funding This work was funded by Action Medical Research. Vertebroplasty materials were provided by Stryker and by Orthovita. We can confirm that this abstract has not been published previously in whole or substantial part, and the findings have not been presented previously at a national meeting.