Two case reports of 'locked spondyloptosis': the most severe traumatic cervical spondyloptosis with locked spinous process and vertebral arch into the spinal canal.

To the best of our knowledge, this is the first report of traumatic 'locked spondyloptosis' of the spinous process and vertebral arch into the spinal canal. Although high-grade compressive-extension injuries are usually repaired using a combined anterior-posterior approach, repair is possible with a posterior approach alone with reliable anchors, such as pedicle screws or multiple lateral mass screws. Urgent open reduction may be required for locked spondyloptosis when closed reduction is invalid due to rigid locking of the cervical spine.