Fate of the transpedicular intervertebral bone graft after posterior stabilisation of thoracolumbar fractures.

The authors present a retrospective clinical and radiological study addressing the outcome after posterior stabilisation of thoracolumbar fractures with intervertebral fusion via transpedicular bone grafting. The study included computed tomographic (CT) scan after implant removal for analysis of the intervertebral fusion and incorporation of the intervertebral bone graft and its influence on postoperative re-kyphosing. Twenty-nine patients with acute fractures of the thoracolumbar spine, treated between 1988 and 1995 at the Department of Trauma Surgery, Hannover Medical School, underwent posterior stabilisation and interbody fusion with transpedicular cancellous bone grafting. This study group was followed clinically and radiologically for a mean of 3.5 years. All patients underwent spiral CT scan with sagittal reconstruction after implant removal. Twenty-four type A, four type B, and one type C lesion were posteriorly stabilised and transpedicular intervertebral bone grafting was performed. The operative time averaged 2 h 50 min, the intraoperative fluoroscopy time 4 min 7 s, and the mean intraoperative blood loss was 376 ml. Four patients out of six with an incomplete neurologic lesion (Frankel/ASIA D) improved to Frankel/ASIA grade E. Two complications were observed: one delayed wound healing and one venous thrombosis with secondary pulmonary embolism. Compared to the preoperative status, our follow-up examinations demonstrated permanent social sequelae: the percentage of individuals able to do physical labor was reduced, whereas the proportion of unemployed or retired patients increased. The assessment of complaints and functional outcome with the Hannover Spine Score reflected a significant difference ( P<0.001) between the status before injury (96.6/100 points) and at follow-up (64.4/100 points). The radiographic follow-up revealed a mean loss of correction of 7.8 degrees ( P<0.005). CT scans after implant removal showed an interbody fusion and incorporation of the transpedicular bone graft in ten patients (34%). In another ten patients (34%), the CT scans demonstrated the interbody fusion at the anterior and posterior walls of the vertebral body via direct contact due to collapse of the disc space. In these patients, the bone graft was not incorporated and no central interbody fusion could be found. In nine patients (31%) neither interbody fusion nor incorporation of the transpedicular graft was achieved. A frequent and reliable intervertebral fusion could not be achieved with the described technique of transpedicular bone grafting. The ineffectiveness of the intervertebral graft was found to be a reason for postoperative re-kyphosing.

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 stabilization of thoracolumbar fractures with internal fixator and interbody fusion via transpedicular bone grafting. SUMMARY OF BACKGROUND DATA: The posterior approach, using an internal fixator, is a standard procedure for stabilizing the injured thoracolumbar spine. Transpedicular bone grafting was invented by Daniaux in 1986 for achieving an interbody fusion. Pedicle screw fixation with additional transpedicular fusion has remained controversial because of inconsistent reports and a lack 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 examined. RESULTS: According to the Magerl classification, 33 patients sustained Type A, 13 Type B, and 10 Type C fractures. Three patients with incomplete paraplegia returned to normal. In one case of complete paraplegia, no change occurred. The mean operative time was 3 hours. In this study, two complications (3.6%) were observed: one iatrogenic vertebral arch fracture without consequences 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 share of unemployed or retired patients doubled (4 to 8 patients). At the time of follow-up examination, only 21 of 42 patients continued in sports. The assessment of reported problems and functional outcome with the Hannover spine score reflected a significant difference between the status before injury (96.6/100 points) and at the time of follow-up evaluation (71. 4/100 points) (P < 0.001).The radiographic assessment in the lateral plane (Cobb technique) demonstrated a significant (P < 0.001) mean restoration from an initial angle of -15.6 degrees (kyphosis) to +0. 4 degrees (lordosis). Serial postoperative radiographic follow-up assessment showed progressive loss of correction. At follow-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 examination was noted. The addition of transpedicular cancellous bone grafting did not decrease the loss of correction. Computed tomography scans after implant removal were performed in nine cases: Only three of nine patients showed evidence of intervertebral fusion. No correlation could be found between the Magerl classification and radiographic outcome. However, the preoperative wedge angle of the vertebral body correlated significantly with the postoperative loss of reduction. CONCLUSIONS: Because of the disappointing results from this study, the authors 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.

The pulmonary artery catheter: a diagnostic adjunct for fat embolism syndrome.

Available objective tests for fat embolism are neither sensitive nor specific. We performed frozen-section analysis of blood aspirated from a pulmonary artery catheter in a trauma victim with fat embolism syndrome and found marked levels of pulmonary microvascular blood fat. The amount of fat detected in this patient with long bone fractures was higher than that observed in a pilot study of this technique in cardiopulmonary bypass patients. This technique provided diagnostic support of our clinical findings. The procedure may prove useful in patients with an equivocal diagnosis of fat embolism or when the cause of posttraumatic acute pulmonary insufficiency is unknown.