gms | German Medical Science

Background: Fractures of the C1/2 region can be complicated by osteoporosis, tumors, congenital abnormalities or additional injuries. Even in straight forward Anderson 2 dens fractures there is a considerable rate of pseudoarthrosis. This requires different strategies and instrumentations.

Materials and methods: From 1994 to 2014 64 patients were treated by the senior author. 16 had dens fractures associated with severe osteoporosis, 15 with C1-fractures, 7 with joint fractures, 6 with tumors, 3 with Os odontoideum, 4 with trauma to the C4-7 level, and 11 had pseudoarthrosis after previous surgeries. 2 Patients had a C0-C1 dislocation. 45 patients were neurologically asymptomatic, 14 had myelopathy and 3 a complete transverse syndrome.

Results: Treatment was surgical instrumentation from ventral (27), dorsal (31), or both (6). In osteoporosis patients with Anderson 2 fracture or additional C1 fractures we perform a ventral triple screw fixation with a longitudinal dens screw and 2 ventral placed transarticular C1/2 screws. Fractures with non union of the ventral instrumentation are treated with dorsal transarticular screws combined with a modular C1 claw (Olerud-fixateur). If the C1-arch is also fractured we perform a transpedicular C1-2 Fusion. Plasmocytomas were resected and stabilized by additional vertebroplasty. In 5 patients we performed a transoral resection of pannus or tumor, in 1 patient a direct single screw osteosynthesis of a C1 joint-fracture was sufficient. 1 patient suffered from a large clivus meningioma and C1/2-fracture and was treated by craniotomy, tumor removal and transpedicular C1/2-fusion in semisitting position. 3 patients refused surgery due to the risks. Complications were remaining instability in 7 patients, screw dislocations in 3 patients, injuries to the vertebral artery in 2 patients and prolonged intensive care treatment in 3 patients. We had no mortality and no wound infection.

Conclusion: Ventral triple screw osteosynthesis of dens and C1/2 joints is a good option in patients with severe osteoporosis or dens fractures associated with C1 arch fractures. Spinal canal stenosis may be severe, worsen over time and can be treated by transoral resection of the compressing tissue followed by dorsal fusion. If the C1 arch is intact, an Olerud fixateur with transarticular C1/2 screws, fixed C1-clamp and bone grafting leads to a reliable solid fusion. Modular mini-fixateur-interne systems are easier to implant and the better alternative if there are additional fractures of the C1-arch or other levels. Tumors should be removed, histologically evaluated and treated by radiation or chemotherapy if necessary.