Surgical treatment of atlantoaxial dislocation using a novel posterior atlantoaxial screw-rod fixation system: a retrospective controlled study.

Abstract

We developed a novel posterior atlantoaxial screw-rod (PASR) fixation system to manage atlantoaxial dislocation (AAD) and compared it with a conventional PASR fixation system. The novel system was designed to simplify the fixation procedure and achieve direct reduction of irreducible AAD without the need for surgical release. To perform a comparative assessment of clinical and radiological outcomes between our novel PASR fixation system and a conventional PASR fixation system. The current literature provides limited evidence on the efficacy of this novel PASR fixation system for managing irreducible AAD. A novel PASR fixation system was designed to address the limitations of a conventional PASR fixation system, and it included C1 reduction screws, C2 fulcrum screws, and antirotation rods. From June 2016 to June 2021, 39 patients with AAD underwent a single posterior approach. Of these 39 patients, 21 were treated with the conventional PASR fixation system and 18 were treated with the novel PASR fixation system. The imaging and clinical data before and after the surgery were retrospectively analyzed. All 39 patients were successfully treated, and there were no vascular or neurological complications. Both groups demonstrated significant improvements in the atlantodental interval (ADI), Japanese Orthopaedic Association (JOA) score, visual analog scale pain score, and Neck Disability Index at the final follow-up. The operative time was shorter, postoperative ADI was better, and JOA score at follow-up was higher in the novel PASR group than in the conventional PASR group. No cases of implant loosening or screw fracture were observed. All patients achieved complete anatomical reduction postoperatively, and there was radiographic evidence of solid bony fusion within 12 months. A posterior approach with our novel PASR fixation system is safe and effective for the treatment of AAD. Compared with a conventional PASR fixation system, our novel PASR fixation system can simplify the operation and provide a better reduction effect. This novel fixation system is expected to facilitate the procedure of atlantoaxial fixation and achieve reduction of irreducible AAD without release.