Endoscopic-assisted transoral atlantoaxial joint release using plasma radiofrequency ablation in management of irreducible atlantoaxial dislocation: a proof-of-concept case series with technical notes

Irreducible atlantoaxial dislocation (IAAD) is a potentially life-threatening condition and remains surgically challenging. In selected patients, anterior C1-2 release followed by posterior reduction and fusion is effective, but traditional transoral anterior release is technically demanding. Endoscopy and plasma radiofrequency ablation (PRA) may improve visualization and soft tissue handling in a confined corridor, but their combined use for IAAD has been rarely reported. This study aimed to describe an endoscopic-assisted transoral atlantoaxial joint release using PRA and to report preliminary feasibility, procedural safety, and clinical/radiographic outcomes in patients with IAAD. We retrospectively reviewed five consecutive patients with IAAD who underwent endoscopic-assisted transoral C1–2 release using PRA, followed by posterior reduction and fusion. Clinical outcomes were assessed with the Japanese Orthopaedic Association (JOA) score and Odom criteria. Radiographic correction was evaluated using the clivus–axial angle (CAA) and cervicomedullary angle (CMA). Perioperative outcomes included operative time, blood loss, airway management, wound healing, and approach-related complications. Fusion was assessed on follow-up computed tomography. The mean age was 57.4 years, and the mean follow-up was 33 months. Two patients had restricted mouth opening. Mean total operative time was 229 min (transoral stage 130 min), with a mean estimated blood loss of 170 mL. All patients were extubated in the operating room; none required reintubation, tracheostomy, or intensive care. No cerebrospinal fluid leak, neurological deterioration, posterior pharyngeal wound complication, surgical site infection, dysphagia, or implant-related failure occurred. CAA improved from 117.9° to 143.0°, and CMA improved from 128.5° to 152.9°. Solid fusion was achieved in all cases. JOA scores improved from 8.2 to 14.2, and 80% of patients were rated excellent/good by Odom criteria. This proof-of-concept series suggests that endoscopic-assisted transoral C1–2 release using PRA can facilitate subsequent posterior reduction and fusion in selected IAAD patients, including those with restricted mouth opening, with encouraging early safety and clinical/radiographic improvement. Given the small retrospective, non-comparative design and the inability to disentangle PRA-related effects from adjunctive drilling, larger multicenter comparative studies are needed to validate these preliminary findings and clarify the specific contribution of PRA within the procedure.