Application of load sharing classification to fractures of the dorso-lumbar spine

ABSTRACT

Transpedicular fixation has begun to be widely used for the stable internal fixation of the injured vertebral segments. Our objectives is to evaluate the surgical management of thoraco-lumbar injuries using posterior transpedicular screws only and to verify the need for second stage anterior surgery for decompression and fusion of the injured vertebra. Sixteen patients had crush cleavage fracture of dorsal and lumbar spine. They were all fixed by pedicular screw system. Five patients had a second stage of anterior decompression and strut grafting. Patients were evaluated for type of injury, level of injury, deformity correction, neurological deficit and instrumentation failure. Applying the load sharing score by Mc Cormack, 1994, we found that the predictability of the score to define the need for a second stage anterior surgery was 33% in the unstable fracture scoring 7 and above, and was 73.4% correct in the relatively stable fractures. No patient deteriorated neurologically after surgery. We had two cases of screw loosening and one case of rod breakage. It is suggested to raise the score of instability to eight and above, as in this series, cases of score seven and less healed uneventfully on posterior surgery alone