To evaluate the clinical outcome and reliability of mixed bone in the process of posterior spinal fusion for the treatment of thoracolumbar spine fractures. In order to eliminate donor site morbidity which is linked to the use of autogenous bone graft, a new surgical procedure mixing autogenous bone chips that were obtained from local decortication of the posterior element of the spine with highly purified calf bone (Lubboc) is studied.

We followed up 9 patients who had undergone autogenous bone graft and 9 patients who had undergone mixed bone graft for more than 12 months out of 33 patients who underwent posterior spinal fusion for thoracolumbar spine fractures between July 1993 and July 1997.

Radiographic results indicated solid bony union in 17 of 18 cases regardless of the graft materials. Based on each follow-up evaluation, it was found that the increase in kyphotic angle was related to elapsed time rather than to the type of graft materials.

It appears that the new surgical method of bone graft with highly purified calf bone can be a reliable alternative for achieving stable posterior spinal fusion as long as bone chips large enough to fill the interlamina space can be obtained.