LAUSR

A 44-year-old woman, with a childhood history of motor vehicle accident, was referred to neurosurgery due to progressive tetraparesis, inability to walk, generalized hyperreflexia, and bilateral extensor plantar reflexes (American Spinal Injury Association Impairment Scale D/Japanese Orthopaedic Association score 7), without bowel/bladder dysfunction. Dynamic MRI (Figures 1 and 2) showed spinal cord edema/gliosis at the C1 level and atlanto-axial subluxation. During flexion, severe spinal canal stenosis was observed, confirming atlanto-axial instability. Posterior arthrodesis was performed and resulted in resolution of instability with no neurologic deterioration after 3 months. Dynamic MRI in the supine position can be an accurate technique to unveil occult cervical canal stenosis.1,2 Although most cases are revealed or aggravated during extension, flexion should also be tested.2