Endoscopic-Assisted Posterior Atlantoaxial Fusion: Technical Innovation and Clinical Experience

Atlantoaxial instability or dislocation requires reliable posterior stabilization and fusion to prevent neurological deterioration. Although conventional Goel-Harms posterior fixation provides effective biomechanical stability, it usually requires extensive posterior cervical muscle dissection and may be associated with substantial blood loss, postoperative axial pain, and soft-tissue morbidity. Despite the advantages of minimally invasive endoscopic techniques in spinal surgery, clinical evidence regarding their application in the management of AAI/D remains limited. In this study, we report a clinical series of endoscopic-assisted atlantoaxial lateral mass fusion, provide a detailed description of the key surgical steps, and evaluate its technical feasibility, safety, and early clinical outcomes.

Sixteen patients diagnosed with AAI/D underwent endoscopic-assisted posterior atlantoaxial fusion. The procedure utilized a uniportal endoscopic system through a 2.5-3.0 cm incision, enabling direct visualization of the C1-C2 lateral mass joint, precise screw placement, and intra-articular bone grafting under continuous irrigation. Radiographic parameters, neurological function (JOA), pain (VAS), and neck disability (NDI) scores were assessed pre- and postoperatively.

All surgeries were successfully completed without intraoperative neurovascular injury or hardware malposition. The mean operative time was 103.06 ± 9.55 min, and the mean blood loss was 40.06 ± 9.28 mL. The atlantodental interval (ADI) decreased from 5.14 ± 1.51 mm preoperatively to 3.37 ± 0.52 mm postoperatively (p < 0.001), and C1-C2 joint height increased from 2.98 ± 0.27 mm to 4.37 ± 0.49 mm (p < 0.001). At 3 months, bone fusion was achieved in 93.8% of patients. Clinical outcomes improved compared with preoperative values, including JOA score (8.44 ± 0.89 to 13.31 ± 1.20), VAS score (8.00 ± 0.73 to 2.25 ± 0.45), and NDI score (31.88 ± 1.93 to 12.88 ± 1.26).

This study introduces a novel minimally invasive technique for managing atlantoaxial instability using uniportal endoscopic-assisted posterior fusion. The combination of direct endoscopic visualization, accurate screw-rod fixation, and controlled intra-articular bone grafting offers reliable joint stabilization with reduced tissue disruption. Clinical outcomes suggest this approach may facilitate rapid recovery and improved perioperative safety, offering a valuable addition to current surgical strategies for AAI/D.