Upper thoracic spinal cord injury without vertebral bony lesion: a report of two cases.

STUDY DESIGN: Case report. OBJECTIVES: To describe a rarely reported type of upper thoracic spinal cord injury without vertebral bony lesion in two cases with multiple trauma. SUMMARY OF BACKGROUND DATA: Because it is supported by the stiffness of the rib cage, the upper thoracic spine has greater stability than the cervical and lumbar regions, and thus its fracture or fracture dislocation is less frequent. Nevertheless, when fracture or fracture dislocation of upper thoracic spine occurs, spinal cord involvement and severe concomitant injuries are frequently associated. METHODS: Two cases who were suspected to have thoracic spinal cord injuries were referred to our emergency center: a 19-year-old girl presented with paraparesis after her motorcycle collided with a truck, and a 63-year-old male involved in an industrial accident presented with paraplegia. RESULTS: Radiograph and computed tomography scan showed no abnormality or dislocation in the vertebral bodies in these two cases, although the upper thoracic spinal cord injuries were suspected by clinical features. Magnetic resonance images detected abnormal signals, suggesting spinal cord injuries, and these signals each emanated from levels that coincided with the observed clinical features. CONCLUSIONS: Transient subluxation or displacement might have caused the upper thoracic spinal cord injuries after the support of the rib cages was temporarily lost on application of excessive force, although such findings could not be confirmed by imaging procedures.