Fate of the intervertebral disc and analysis of its risk factors following high-energy traumatic thoracic and lumbar fractures: MRI results of minimum five years after injury

Objective: Disc degenerative disease is regarded as the primary cause of low back pain. The purpose of this study was to clarify the fate of Intervertebral disc (IVD) following the traumatic event through long-term follow-up and to identify the risk factors for irrevocable degeneration.

Methods: 78 non-operative patients who had traumatic fracture of the thoracic or lumbar at minimum 5 years before were enrolled. Disc degeneration was assessed by modified Pfirrmann grading system. The Acceleration of disc degeneration (ADD) was defined as the difference of grade between IVD adjacent to fractured vertebra and their neighbors with increasing grade from 0 to 7. A novel classification of Endplate injury (EPI) with increasing severity from type I to III was proposed based on the injured morphology. The long-term fate of IVD adjacent to fractured vertebra and risk factors for ADD were analyzed.

Results: The mean time of last follow-up was 15.4 ± 10.8 years (range 5-49 years) after injury. 138 (68.66%) IVDs were graded 0 of ADD, 44 (21.89%) were 1-3 and 19 (9.45%) were 4-7. Multivariate binary logistic regression analyses showed that injured posterior ligamentous complex (PLC) and EPI type III were independent risk factors for ADD.

Conclusions: Injured PLC and EPI type III were independent risk factors for ADD in patients with traumatic thoracic or lumbar fracture. For such patients without risk factors for ADD, the non-intervertebral fusion should be given a priority if surgery is necessary.