Introduction: The role of transpedicular bone graft for the stability after dorsal instrumentation of fractures of the thoracolumbar spine is still not clear whereas the morbidity of harvesting the bone from the iliac crest is evident. In a clinical study we examined the clinical outcome, radiological signs of instability and the vitality of the bone by MRI.

Methods: We examined 45 patients who underwent posterior instrumention for fractures of the thoracolumbar spine between 1988 and 1997 and had removal of the implants more than 3 months ago. All patients had received a interspinal and interlaminar bone graft, 23 patients had received an additional transpedicular bone graft. We measured the clinical outcome by a standardized questionnaire and the stability of the spondylodesis by native and functional Xrays. The vitality of the transpedicular bone graft was examined by MRI.

Results: There were not significant differences in both study-groups concerning the clinical outcome. In both groups we saw one case with radiological signs of instability. In the MRI-examination 18 of the 23 patients with a transpedicular bone graft showed a vital graft. In 5 cases the transpedicular bone graft showed no increase of the signal intensity after contrast media which was interpreted as a avital graft.

Discussion: Although the support of the anterior column in the posterior instrumentation by a transpedicular bone graft is theoretically meaningful we saw no correlation to the clinical outcome. Considering our results and the donor site morbidity, the use of transpedicular bone graft must be discussed critically.