Cervical spondylotic myelopathy can be misdiagnosed as inflammatory myelitis leading to unnecessary immunotherapy and delayed definitive surgical treatment.

To describe the utility of flexion-extension MRI in inflammatory and undifferentiated myelopathies with spinal cord T2-hyperintensity.

Mayo Clinic patients were identified retrospectively from 12/31/2012-10/24/2023. Inclusion criteria were: 1) Age ≥18 years; 2) Myelopathy; 3) Flexion-extension cervical spine MRI available; 4) Spinal cord T2-hyperintensity on MRI.

Ninety patients that underwent flexion-extension MRI for possible CSM were included, and the median age was 58 years (range, 30-81) with 47 (52%) of male sex. CSM was the final diagnosis in 65 (85% had insidious onset; 12% had accompanying reverse Lhermitte’s phenomenon). Prior to Flexion-Extension MRI being undertaken, 26/65 (40%) with CSM were initially assigned alternative diagnoses and 19 (29%) received immunotherapy for presumed inflammatory myelitis. The median delay to diagnosis in these patients was 15 months (range, 0.5-155). Increased compression on flexion-extension MRI was more likely with a final diagnosis of CSM (55/65 [85%]) than an alternative myelopathy etiology (3/25[12%]: multiple sclerosis, 2; progressive lateral sclerosis, 1). The dynamic changes noted in CSM during flexion-extension MRI included: worse in extension, 47 (85%); worse in flexion, 4 (7.5%); worse in both, 4 (7.5%). Among the 65 patients with CSM, the median length of cord T2-hyperintensity on sagittal sequences was 1 vertebral segment (1-5) and 33/53 (62%) had accompanying enhancement. In 46/65 (71%) decompressive surgery was undertaken at Mayo Clinic and 39/46 (85%) reported some improvement, 4/46 (9%) noted only stability and 3/46 (7%) had some worsening.

Cervical spondylotic myelopathy with spinal cord T2-hyperintensity was frequently misdiagnosed as myelitis in this series often leading to unnecessary immunotherapy and delayed definitive treatment. Flexion-Extension MRI is a straightforward MRI technique which can show positional cord compression and allow more rapid diagnosis and earlier treatment of unrecognized cervical spondylotic myelopathy.