Identification and measurement of cervical spinal cord atrophy in neuromyelitis optica spectrum disorders (NMOSD) and correlation with clinical characteristics and cervical spinal cord MRI data

Introduction The spinal cord is one of the two main targets of neuromyelitis optica (NMO). The aim of this study was to highlight cervical spinal cord atrophy in NMO patients as compared to controls and to assess correlations between atrophy and clinical characteristics and cervical spinal cord MRI data. Methods This prospective study investigated 15 patients with a diagnosis of NMOSD and 15 healthy controls. The whole cervical spinal cord was explored by MRI. The cross-sectional area (CSA) was estimate at every level of cup. This measurement was then averaged on the whole cervical spinal cord, providing a single measurement for every subject, denoted as mean CSA. Results Mean CSA was 68.5 mm2 in the population of NMO patients and 72.8 mm2 in the population of healthy subjects. NMO patients had significantly smaller cervical spinal cord area than healthy controls (T test = 0.009). Cervical spinal cord atrophy was associated with clinical signs of medullary involvement (T test = 0.0006). There was a tendency toward a relation between cervical spinal cord atrophy and the Expanded Disability Status Scale (EDSS) (T test = 0.07). This correlation seems statistically significant (T test Conclusion This study provides the first evidence of cervical spinal cord atrophy in NMOSD by studying the entire cervical spinal cord. Upper cervical spinal cord atrophy was substantially correlated to clinical disability and seems more involved in the development of clinical disability in NMOSD patients in comparison to the lower cervical spinal cord.