Transoral Osteosynthesis C1 as a Function-Preserving Option in the Treatment of Bipartite Atlas Deformity A Case Report

Study Design. A case report about transoral osteosynthesis C1 as a function-preserving option in the treatment of bipartite atlas deformity. Objective. To illustrate a new method, which preserves the function of the C1-C2 joint in young patients. Summary of Background Data. To the authors, knowledge, bipartite atlas deformity are usually treated conservatively by immobilization or traction or surgically by posterior fusion C1-C2. Methods. A 20-year-old man, who complained about occipitocervical pain and cervical activities limitation, and presented with a 3-month history of weakness and numbness of all 4 limbs after sustaining a minor head trauma. Computed tomography scan showed anterior arch midline defect, posterior arch midline aplasia. Steel plate fixation by transoral approach was performed to repair bipartite atlas deformity. Results. In 1-month follow-up, occipitocervical pain disappeared. The patient had significant improvement over next 3 months. In 6-month follow-up, we observed bony union of anterior arch of atlas without abnormal manifestations. The postoperative rotation in the atlanto-axial joint was returned to normal. The patient had no symptoms of postoperative instability of C1-C2. Conclusion. We described a rare association of an anterior arch midline defect, posterior arch midline aplasia. The natural history of patients with bipartite atlas deformity suggests that these people have a potentially precarious existence. Transoral osteosynthesis of the anterior ring and the lateral masses of C1 is a new technique that allows maintenance of rotatory mobility in the C1-C2 joint and restoration of congruency in the atlanto-occipital and atlantoaxial joints.