Trivial trauma with atlantoaxial instability in Os odontoideum: Need for cervical fusion

Background: Os odontoideum is a congenital anomaly or a posttraumatic event of the C2 vertebra (dens), in which the odontoid process is separated from the body of the axis by a transverse gap. Trivial trauma aggravates the condition resulting in atlantoaxial dislocation (AAD) which needs stabilization. Materials and Methods: In our study, we have five patients with os odontoideum, who had developed quadriparesis after minor cervical trauma. All of them underwent C1–C2 posterior stabilization by Harms technique (C1 lateral mass screw and C2 pedicle screw with rod reconstruction), and postoperatively, all the five patients showed a significant improvement from the quadriparesis. Results: All the patients in this case series showed significant improvement in motor power following posterior C1 C2 stabilization. Conclusion: AAD following a trivial trauma in cases of os odontoideum needs to be stabilized to form solid fusion. To achieve that, the Harms technique of C1–C2 fusion is a very effective method.