Burst fracture of the fifth lumbar vertebra: results of posterior internal fixation and transpedicular bone grafting

Abstract.

Burst fractures of the fifth lumbar vertebra are rare, and there are only a few reports on this subject, which is characterised by its unique anatomical and biomechanical features. This retrospective analysis reports on ten patients whose fractures of L5 were stabilised with a short internal fixator in combination with a posterior fusion as well as transpedicular bone grafting. The average follow-up period was 22 months. Radiometric data were surveyed and compared to the functional results. The height of the fractured vertebra remained nearly unchanged throughout the course. Loss of lordosis of 4° in the upper disc space and 4° in the lower disc space were observed postoperatively. At the time of follow-up, the values of segmental lumbar lordosis were significantly below the preoperative level. The narrowing of the neural canal was reduced from 57% to 28% with the surgical intervention. However, there was no correlation between the functional and the radiological outcome. Neurological deficits were documented in two patients, which declined during the course. There were no severe postoperative complications. The results of the present study demonstrate that the described surgical procedure in fractures of the fifth lumbar vertebra does not promote an anatomic restoration of the fractured vertebra, nor of the segmental lordosis. However, the clinical results do not correlate with the radiological outcome. Nonoperative treatment with early mobilisation without external support seems to be the treatment of choice.