Unstable, displaced odontoid fractures of the dens axis (spinal process of the second cervical vertebra) can be fixed and stabilised either from the front (anterior) with one or two tension screws (see also: age-related fractures of the cervical spine) or from the back (posterior) screw fixation, e.g. with the help of a segmental screw and rod system (Fig. D).

The example shows a displaced, trauma fracture of the dens (Type 2 according to Anderson and D'Alonzo). The injury was treated using the surgical technique as first described by Harms. The procedure is suitable for patients - even with reduced bone quality (osteoporosis) - and ensures superior primary stability.

The 74-year-old lady lives at the coast of the Baltic Sea and regularly visits the beach. A heavy roofed wicker beach chair fell on her head. In addition to a laceration at the back of the head, she immediately experiences severe neck pain. Because her neck pain does not improve after three days, she goes to the nearby hospital for examination. After an X-ray examination, it becomes clear that she has broken the second cervical vertebra. A CT shows the findings even more clearly (Fig. A - green arrow). The fracture is displaced. In addition, osteoporosis and severe arthritis of the cervical vertebral joints are present.

In the case of osteoporosis, optimal anterior screw fixation is often not possible and may lead to problems (screw loosening, pseudarthrosis).

Therefore, segmental fusion of the first and second cervical vertebrae (C1-C2) with four polyaxial screws (Fig. B, C) and two rods (Fig. D) is the method of choice in this situation.

In the postoperative X-ray and CT images (Fig. B-D), a bone graft was transplanted between the screws and rods dorsal to the vertebral arches. This offers permanent and stable bridging of the fracture gap.