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 atlantoaxial 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.