Cervical atrophy following complete thoracic spinal cord injury: Insights from a multinational cohort

BackgroundSpinal cord injury (SCI) results in neurodegeneration both at and above the lesion site. While cervical cord atrophy is well characterized in populations of mixed cervical, thoracic and/or lumbar injuries, the remote morphological changes in cervical cord following thoracic SCI remain unclear. The present study aimed to quantify cervical spinal cord morphology at C2-C3 in individuals with thoracic SCI and compare these metrics to matched controls. MethodsParticipants were 60 adults with chronic thoracic SCI and 60 neurologically healthy controls matched for age and sex. Extracted cervical metrics included mean cross-sectional area (CSA), antero-posterior (AP) and right-left (RL) diameters, eccentricity, solidity, orientation, and cord length. Group differences were assessed using linear mixed models adjusted for age, sex and scanning sites. Impacts of experiencing SCI-related chronic neuropathic pain on these metrics were explored. ResultsCompared to controls, the thoracic SCI group showed significantly reduced cervical CSA, along with smaller AP and RL diameters, consistent with remote atrophy. Eccentricity was increased, indicating a more flattened cord profile. Solidity, orientation, and cord length showed no group differences, supporting metric reliability and the absence of segmentation artefacts. Compared to controls, increased eccentricity was driven by people with SCI who experience chronic neuropathic pain. The presence of chronic neuropathic pain did not significantly influence other morphometric outcomes. ConclusionsThoracic SCI is associated with significant remote cervical cord degeneration, even in the absence of direct cervical injury. Results highlight that neurodegenerative processes propagate along ascending and descending spinal pathways. Cervical morphometry metrics, particularly CSA and eccentricity, may represent biomarkers of distal neurodegeneration following thoracic SCI, and inform future therapeutic strategies.