Posterior rotating rod reduction strategy for irreducible atlantoaxial subluxations with congenital odontoid aplasia.

Study Design: Applying rotating rod techniques to reduce irreducible atlantoaxial dislocation.

Objective: To spare the occipital-C1 motion by the strategy in reduction of before surgery irreducible atlantoaxial dislocation with obvious neurologic symptoms and congenital odontoid aplasia.

Summary Of Background Data: The treatment of atlantoaxial dislocation (AAD) is a challenging problem for most surgeons. Posterior surgical stabilization of C1 and C2 include C1-C2 transarticular screws, or C1 lateral with C2 pars screws. These constructs, however, are based on preoperative reductions. When preoperative skull reduction fails and myelopathic symptoms coexist, long-segment cervico-occipital fusion and decompression are usually the only practical choice.

Methods: The authors explored a different surgical technique to spare the axial occipital joints by rotating rods in polyaxial C1, C3 lateral mass, and C2 pars screws, functioning as a lever analogue. Three before surgery irreducible AAD cases with obvious neurologic symptoms and congenital odontoid aplasia were successfully reduced and fused with this procedure. The authors used intraoperative somatosensory-evoked potential monitoring and intraoperative fluoroscopy. Preoperative skull traction was employed to distract and help extend the atlantoaxial complexes.

Results: Three C1-C2 dislocations were reduced completely without any deterioration of neurologic signs. Cervical myelopathic symptoms recovered soon after the operation. No atlantoaxial subluxation recurred. They returned to their normal work and/or activities.

Conclusion: The rotating rod strategy is a viable option to reduce and fuse C1-C3 for AAD with odontoid aplasia. It spares the occipital-C1 motion.