Post-traumatic lower cervical spine instability: Arthrodesis clinical and radiological outcomes at 5 years

BackgroundAnterior cervical fusion is widely used to treat spinal injuries. Radiological evidence of disc abnormalities may develop on either side of the fused segment, raising concern about the potential for inducing adjacent-segment disease. Here, we report the long-term clinical, functional, and radiological outcomes after anterior cervical fusion.HypothesisAnterior cervical fusion influences the development of adjacent-segment disease.Materials and methodsIn a retrospective study, 15 patients aged 17 to 50 years were re-evaluated more than 5 years after anterior spinal fusion to treat post-traumatic cervical-spine instability. We used the Neck Disability Index (NDI) to assess function. Static and dynamic radiographs of the cervical spine were obtained.ResultsNDI values indicated good clinical and functional outcomes, and fusion was achieved consistently. Adjacent-segment disease was a consistent finding at last follow-up but induced no neurological manifestations. Complete fusion of a level adjacent to the treated level was noted in 2 patients. Revision surgery for adjacent-segment disease was not required in any patient.ConclusionThe causative factors of adjacent-segment disease are controversial. Disc degeneration is a normal manifestation of the ageing process. Nevertheless, disc disease is more prevalent at levels adjacent to interbody fusion than in the normal population, suggesting accelerated disc degeneration due to increased loading of the adjacent levels. Furthermore, lesions that are missed during the pre-operative work-up may play a role, as the available investigations do not always have high negative predictive values.Level of evidenceLevel IV, retrospective study.