Irreducible anterior atlantoaxial dislocation - One-stage treatment with a transoral atlantoaxial reduction plate fixation and fusion. Report of 5 cases and review of the literature

Study Design. Retrospective report of five surgical cases and review of the literature. Objectives. To report the clinical application of a novel internal fixation device in the treatment of irreducible atlantoaxial dislocation with ventral spinal cord compression. Summary and Background Data. Irreducible atlantoaxial dislocation with ventral spinal cord compression is difficult to treat. Traction is not uniformly successful at either reducing the dislocation or decompressing the spinal cord. Direct anterior decompression of the spinal cord may be necessary, in addition to the need for surgical stabilization of the upper cervical spine. Numerous methods have been described for surgical stabilization following transoral decompression, which generally require a second-stage posterior instrumentation and fusion procedure. Complication rates remain noteworthy for any of these strategies. Methods. A novel transoral atlantoaxial reduction plate (TARP) system was designed to facilitate a one-stage anterior operation capable of simultaneously decompressing the ventral spinal cord as well as reducing and fusing the atlantoaxial segment. The procedure and TARP implant has been employed for five patients with irreducible atlantoaxial dislocation because of trauma or congenital disorders. Following transoral decompression and excision of scar, ligament and osteophytes, the TARP was used to affect reduction and fixation of the atlantoaxial joints. The decorticated atlantoaxial joint surfaces were grafted with autogenous iliac crest bone. The histories of these cases were reported in detail. Results. The five case examples demonstrate the efficacy of this one-stage approach to the surgical treatment of irreducible anterior atlantoaxial dislocation with spinal cord compression. The role of the TARP in affecting and maintaining the reduction while promoting successful fusion is illustrated. Conclusion. The authors' one-stage anterior procedure employing their TARP for the surgical treatment of irreducible anterior atlantoaxial subluxation was effective in these five cases. This method was able to avoid theneed for interval traction and/or a second stage posterior instrumentation and fusion procedure.