Usefulness of Somatosensory Evoked Potentials in Non-traumatic Spinal Cord Injury in the Absence of MRI Abnormalities: A Case Report.

Non-traumatic spinal cord injury (ntSCI) in childhood rarely occurs during activities of daily living, such as stretching, surfing, or physical education classes. Its pathogenesis remains to be elucidated; however, excessive spinal extension has been suggested as the causative etiology. A previously healthy 14-year-old Japanese girl ran many shuttles in her physical education class and suddenly experienced back pain, followed by severe muscle weakness in the lower extremities. As she was unable to walk independently, she was admitted to the hospital for investigation. Upon admission, she exhibited left-dominant paralysis of the lower extremities, with an increased left patellar tendon reflex, although the deep sensory and cranial nerves were preserved. Spinal MRI, including diffusion-weighted imaging, revealed no abnormalities on days 1 and 24. However, somatosensory evoked potentials (SEPs) on day 22 showed significant left-sided prolongation of the central conduction time (CCT) between N20 and P38, which was clinically consistent with the side of her left-dominant paralysis. We diagnosed the patient with non-traumatic acute spinal cord injury associated with excessive exercise and initiated rehabilitation immediately. She was gradually able to walk without support, but the abnormality of the SEPs - as the left side prolonged the CCT between N20 and P38 - remained on day 116. We consider that SEPs could be an alternative method for detecting occult spinal lesions in children, especially in cases where spinal MRI fails to demonstrate the lesion responsible for ntSCI.