Evaluation of ventral stabilization techniques for thoracolumbar fractures by helical computer tomography

Purpose: To assess the volumetric change of the implanted graft in thoracolumbar fractures treated with dorsal and ventral stabilization. Comparison of two methods of ventral stabilization to avoid loss of correction and rekyphosis. Material and Methods: 38 patients with 40 thoracolumbar fractures were treated with a tricortical bone graft of the pelvis (n = 27) or bone cement (SRS: skeletal repair system, n = 13), measuring the volume and the length of the implanted graft by helical CT (Somatom Plus 4, Siemens): after ventral stabilization, preoperative before and six month after removal of the fixateur interne. The bone and SRS volume were assessed as a product of slice thickness and cross-section, the length of the implanted graft was measured by the cranial and caudal table position. Results: Loss of graft volume between implantation and explantation of the fixateur interne was 24.3%, and between implantation and the check six months after removal 40.5%; loss of length until removal 14.6% and between implantation and six months after the removal 24.1%; no difference between the tricortical bone graft and the skeletal repair system. Conclusion: Volumetric and length study assessed by CT shows a loss of volume and length of the tricortical bone graft and the skeletal repair system with no dependence on the used material. CT enables an exact and feasible assessment of the localisation, volume, size and possible complications of the implanted bone graft and SRS. The considerable loss of volume and length of the graft is one of the reasons correction loss and rekyphosis in the stabilization of the thoracolumbar fractures. (orig.)