Abstract Details

Following SCI, lesions of a similar size can result in considerably varying degrees of neurologic recovery. This non-linear relationship between the lesion size and clinical outcome – referred to as the 'anatomical-functional paradox' – has been proposed in preclinical studies to depend on the anatomical localization and orientation of the lesion and injury-spared tissue, but remains understudied in human SCI.

This multi-center study investigated associations between MRI-derived injury-spared spinal cord tissue bridges measured within the first month following spinal cord injury (SCI) and neurologic recovery rates assessed from hospital admission to discharge 3 months post-SCI.

This longitudinal multi-center study includes 134 patients with cervical SCI. Clinical data was assessed at hospital admission and discharge (~3 months post-SCI). Spared spinal cord tissue bridges were quantified from conventional midsagittal T2-weighted images. Tissue bridges' width and localization, patients' age and sex, and center were used in regression models to predict recovery rates of motor, pin-prick, and light touch scores 3 months post-SCI, adjusted for baseline scores.

Width of tissue bridges was positively associated with motor (p<0.0001), pin-prick (p<0.0001), and light touch score (p<0.0001) recovery rates. Per preserved mm of tissue bridges' width, patients gained 4.4 points in motor, 5.8 points in pin-prick, and 5.9 points in light touch score over 3 months post-SCI.

Quantification of midsagittal tissue bridges is a clinically feasible and eloquent tool providing information on the width and localization of spared functional cord tissue post-SCI. These early neuroimaging biomarkers provide predictive value on baseline clinical scores-adjusted neurologic recovery at discharge. Our results support the theory of an anatomical-functional paradox, are valid across sites, and reliably measurable at different magnetic field strengths and by different raters. Tissue bridges have the potential to be implemented in future clinical trials for improved stratification of SCI patients based on the prediction of neurologic recovery.