Study design: In vitro biomechanical investigation using human cadaveric vertebral bodies.
Objective: To evaluate differences in biomechanical stability of vertebral compression fractures (VCFs) repaired using an expandable titanium mesh implant, with and without cement, as compared with standard balloon kyphoplasty.
Summary of background data: Vertebral augmentation, either in the form of vertebroplasty or kyphoplasty, is the treatment of choice for some VCFs. Polymethylmethacrylate, a common bone cement used in this procedure, has been shown to possibly cause injury to neural and vascular structures due to extravasation, embolization, and may be too rigid for an osteoporotic spine. Therefore, suitable alternatives for the treatment of VCFs have been sought.
Methods: Individual vertebral bodies from 5 human cadaveric spines (from T4 to L5) were stripped of all soft tissues, and compressed at 25% of the intact height using methods previously described. Vertebral bodies were then randomly assigned to the following repair techniques: (1) conventional kyphoplasty, (2) titanium implant with cement, (3) titanium implant without cement. All vertebral bodies were then recompressed at 25% of the repaired height. Yield load, ultimate load, and stiffness were recorded and compared in these groups before and after treatment.
Results: There were no differences in biomechanical data between intact groups, and between repaired groups. In all 3 treatment groups, yield load and ultimate load of repaired vertebrae were similar to that of intact vertebrae. However, the stiffness following repair was found to be statistically less than the stiffness of the intact vertebral body (P < 0.05 for all comparisons).
Conclusion: Based on the biomechanical data, the titanium mesh implant with or without cement was similar to polymethylmethacrylate fixation by kyphoplasty in the treatment of VCFs. Avoiding the adverse effects caused by using cement may be the main advantage of the titanium mesh implant and warrants further study.