Late results of thoracolumbar fractures after posterior instrumentation and transpedicular bone grafting

Study Design. A retrospective clinical study was performed. Objective. To study clinical and radiologic late results after posterior st abilization of thoracolumbar fractures with internal fixator and interbody fusion via transpedicular bone grafting. Summary of Background Data. The posterior approach, using an internal fixat or, is a standard procedure for stabilizing the injured thoracolumbar spine . Transpedicular bone grafting was invented by Daniaux in 1986 for achievin g an interbody fusion. Pedicle screw fixation with additional transpedicula r fusion has remained controversial because of inconsistent reports and a l ack of late results. Methods. Between January 1989 and July 1992, 76 patients with thoracolumbar fractures were operatively treated, and after a mean of more than 3 years, 56 of 62 patients (90%) still alive who had their implants removed were ex amined. Results. According to the Magerl classification, 33 patients sustained Type A, 13 Type B, and 10 Type C fractures. Three patients with incomplete para plegia returned to normal. in one case of complete paraplegia, no change oc curred. The mean operative time was 3 hours. In this study, two complicatio ns (3.6%) were observed: one iatrogenic vertebral arch fracture without con sequences and one deep infection. Compared with the preoperative status, follow-up examinations demonstrated permanent physical and social sequelae: The percentage of individuals able to do physical labor was reduced by half (22 to 11 patients), whereas the s hare of unemployed or retired patients doubled (4 to 8 patients), At the ti me of follow-up examination, only 21 of 42 patients continued in sports. Th e assessment of reported problems and functional outcome with the Hannover spine score reflected a significant difference between the status before in jury (96.6/100 points) and at the time of follow-up evaluation (71.4/100 po ints) (P < 0,001). The radiographic assessment in the lateral plane (Cobb technique) demonstra ted a significant (P < 0.001) mean restoration from an initial angle of -15 .6 degrees (kyphosis) to +0.4 degrees (lordosis). Serial postoperative radi ographic-follow-up assessment showed progressive loss of correction. At fol low-up examination, a mean difference from the postoperative angle of 10.1 degrees was found (P < 0.001). Compared with the preoperative deformity, a mean improvement of 6.1<degrees>(average, -9.7 degrees) at follow-up examin ation was noted. The addition of transpedicular cancellous bone grafting di d not decrease the loss of correction. Computed tomography scans after impl ant removal were performed in nine cases: Only three of nine patients showe d evidence of intervertebral fusion. No correlation could be found between the Magerl classification and radiographic outcome. However, the preoperati ve wedge angle of the vertebral body correlated significantly with the post operative loss of reduction. Conclusions. Because of the disappointing results from this study, the auth ors cannot recommend the additional transpedicular cancellous bone grafting as an interbody fusion technique after posterior stabilization in cases of complete or incomplete burst injury to the vertebral body.