Indication for Anterior Disc Replacement in Fractures of Thoracic and Lumbar Spine Using Magnetic Resonance Imaging - a Prospective Study

The authors made a prospective evaluation of all patients with a thoracic or lumbar spine injury who were indicated for conservative therapy or for posterior transpedicular fixation (TP) surgery in an 18-month period, The group consisted of 89 patients (with average age of 46.04 years), 58 men and 31 women. The follow-up period was 18 to 36 months. The objective of the study was to ascertain, in the first place, the degree of damage to intervertebral discs and vertebral plates with the use of magnetic resonance imaging (MRI), and to evaluate the influence of the injuries on the patients' clinical status while monitoring, for a period of 18 months, changes in the structure and form of the discs, the plates and the vertebral bodies, as well as changes in the intensity of the disc signal during MRI. The results showed that patients with a type-A fracture (AO classification) who underwent a posterior transpedicular fixation procedure tended to develop grosser morphological changes, primarily disc and vertebral body height reduction or even intraspongious herniation of both the upper and the lower disc into the vertebral body at higher age and with a proven higher degree of injury of the posterior longitudinal ligament. Within the same 18-month follow-up period, younger patients tended to have a lower disc signal intensity on STIR-sequence MRI while clinically showing the best functional results. The highest degree of disc and plate damage treated only with TP fixation had significantly worse clinical results than those for lower degree damage. As a result, the evidence of a higher degree of disc and plate damage on the initial MRI has a predictive value and correlates with a poorer clinical status of the patient 18 months post-injury, and may become an important component of the indication algorithm, especially in considering anterior disc replacement.