Progression of adjacent disc degeneration in the cervical spine over ten years: a co-twin case control study

Objectives A single degenerate intervertebral disc is suggested to promote rapid degeneration in its adjacent discs. We validated this hypothesis using discordant co-twin case-control design. Methods 185 pairs of twins were selected from the TwinsUK database having cervical MRI scans at baseline and at follow-up, after 10 years. Isolated disc degeneration (IDD) was diagnosed in subjects having severe loss in disc height (graded 3/3) in a single disc, whilst discs immediately adjacent manifested little or no degeneration (graded 0 or 1). The controls9 ‘adjacent discs’ were considered at the same levels as their affected co-twins. Results Eight twin pairs fulfilled case/control criteria. At follow-up, no significant difference in adjacent disc degeneration between IDD cases and controls remained (p=0.69). Conclusions Using a highly matched case-control design we did not find evidence that lone IDD has an adverse effect on the natural rate of adjacent disc degeneration in the cervical spine. No conflicts of interest Acknowledgements This study was supported by a grant from Globus Inc. Arthritis Research UK supported the imaging costs. TwinsUK. The study was funded by the Wellcome Trust; European Community9s Seventh Framework Programme (FP7/2007–2013). The study also receives support from the National Institute for Health Research (NIHR)- funded BioResource, Clinical Research Facility and Biomedical Research Centre based at Guy9s and St Thomas9 NHS Foundation Trust in partnership with King9s College London.