Application of “key and lock” principle in the treatment of traumatic cervical Spondyloptosis of c6-7: Case report and literature review

Purpose: Traumatic cervical spondyloptosis is a rare clinical pathology that often causes complete paralysis. When a patient presents neurologically intact or incomplete paralysis, the management becomes more complicated. Preservation of neural function and restoration of anatomic alignment collectively remain the golden goals of therapy. There are still few reports on this issue, however, the existing literature did not clearly define severity of injuries and the treatment strategy in such cases. On the occasion of reporting one treated traumatic C6-7 spondyloptosis case, we reviewed existing literatures.

Material and Methods: The patient was a 48-year-old man who had motorcycle accident and was presented with post-operation for right frontal epidural hematoma in 3 days before admitting to hospital. Neurological assessment showed motor strength grade 3/5 in the proximal upper and lower-extremity muscle groups on the right side, and 1/5 on the left side with incontinence of sphincters. X-rays and computed tomography (CT) scan revealed a three-column ligamentous injury with complete anterior displacement of C6 to C7 vertebral body. We applied the “Key - Lock” principle for better understanding of the biomechanics of the injury and found out the favorable strategy. The patient underwent posterior approach with decompression and anterior approach with reduction and anterior cervical discectomy fusion for C6-7.

Results: After 8 months follow-up, the patient had recovered muscular strength in bilateral upper and lower-extremities muscle groups, sphincter function had fully recovered, and he was able to ambulate by himself. Plain radiograph and CT scan showed good aligment and progressive maturation of his fusion procedure.

Conclusion: Traumatic cervical spondyloptosis of C6-7 is a high-energy unstable fracture and rare. This report develops a new principle called “Key and Lock” for more understand the biomechanics of the injury and treatment. Our patient was successfully treated with open reduction, decompression, and anterior cervical discectomy fusion.