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

Abstract

Introduction: Traumatic cervical spondyloptosis, including compressive-extension stage 5 of Allen's classification of cervical spine injuries, is commonly observed; however, cases involving locked spinous process and vertebral arch into the spinal canal are extremely rare.

Case presentation: We present two individuals with spondyloptosis of C7 with locked spinous process of C6 and the vertebral arch into the spinal canal. Closed reduction was unable to be performed due to rigid locking of the cervical spine in the first case, whereas preoperative closed reduction was achieved with mild traction in a prone position after general anaesthesia in the second case. These two individuals underwent spinal fusion via a posterior approach after open or closed reduction. Six months after surgery, both individuals exhibited significant neurological recovery and acquired a stable gait.

Discussion: 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.

Fig. 1. Preoperative computed tomography (CT) scans of the cervical spine.

Three-dimensional reconstruction (a), sagittal (b), and axial (c) CT scans showed C7 spondyloptosis locked C6 spinous process and vertebral arch into the spinal canal. The spinous processes of C5 and C6 had been fractured. The C2–7 lordotic angle was 37°.

Fig. 2. Intraoperative photographs.

a Photograph of the intraoperative cervical spine before reduction. The C6 spinous process and vertebral arch could not be confirmed clearly because they were behind the C7 vertebral arch (white arrow). b Photograph of the intraoperative cervical spine after reduction. The C6 spinous process, vertebral arch, and bilateral facet joint were released from rigid locking. c Photograph of the intraoperative cervical spine after instrumentation and autologous bone grafting.

Fig. 3. Postoperative images.

Postoperative lateral radiograph (a) and computed tomography (CT) scans (b) of the cervical spine. Stabilisation was performed from the C5 to T1 vertebrae with a pedicle screw and lateral mass screws.

Fig. 4. Preoperative images of case 2.

Preoperative sagittal (a) and axial (b) computed tomography (CT) scans of the cervical spine. The C7 vertebra was completely dislocated and the C6 spinous process was locked by the C7 vertebral arch. The spinous process of C6 had been fractured. The C2–7 lordotic angle was 18°.

Fig. 5. Postoperative images of case 2.

Postoperative lateral radiograph (a) and magnetic resonance image (MRI) (b) of the cervical spine. The patient underwent spinal fusion surgery from C5 to T1 vertebra with a pedicle screw and lateral mass screws.