Spinal canal restoration by posterior distraction or anterior decompression in thoracolumbar spinal fractures and its influence on neurological outcome

Summary

Thirty consecutive patients who had suffered unstable fractures and dislocations of the thoracolumbar spine mostly associated with neurologic impairment and bony encroachment on the spinal canal were treated either with Harrington distraction rods combined with sublaminar wires or with the Zielke-VDS device. These patients were subsequently assessed for neurologic outcome, spinal canal clearance, sagittal and coronal spinal deformity correction preoperatively and postoperatively with a minimum follow-up of 26 months. In the follow-up evaluation, the patients who underwent surgery with Harrington rods showed an overall improvement of their neurologic function of 90.9%, whereas all patients who underwent the Zielke operation improved. Preoperatively, positive correlations were found between the level of injury and Frankel grades; the cord lesion tended to demonstrate more severe neurologic deficit when compared with cauda equina ones (P < 0.001). Furthermore, dislocation accompanying the injury resulted in a more severe neurological deficit (P < 0.05). Harrington rods and Zielke device offer sufficient initial correction of the frontal spinal deformity but did not significantly either restore or maintain sagittal plane alignment. The Harrington series showed an overallimprovement of the segmental kyphosis of 26% (NS), with a subsequent loss of correction of 7.38% (NS) on the follow-up observation. The Zielke device produced an immediate, much better correction of the segmental posttraumatic kyphosis of 45% (NS), but a loss of correction of 22.9% (NS) was measured in the follow-up evaluation. Correction of the anterior and posterior vertebral height was shown to be better for the Zielke patient group. The coronal deformity was completely corrected equally well by the Harrington and Zielke devices. There was no statistically significant correlation between the degree of bony encroachment of the spinal canal and the initial Frankel grade. Additionally, no statistically significant correlation was found between correction of the sagittal deformity, restoration of anterior and posterior vertebral height, coronal deformity correction, and clearance of the vertebral canal. Concerning neurological status, no patient in either group was worse in the follow-up evaluation. A significant correlation was found between the age of the patient and the neurological improvement favoring young patients (P < 0.001).