Objective:To evaluate the preliminary clinical application of our self-designed posterior reduction forceps for atlantoaxial dislocation in the reduction and fixation of irreducible atlantoaxial dislocation with simple posterior screw-rod system.Methods:Our posterior reduction forceps was self-designed and developed to assist simple posterior screw-rod system in the treatment of irreducible atlantoaxial dislocation based on the posterior atlantoaxial screw-rod system. A retrospective study was conducted to analyze the clinical data of 5 patients with irreducible atlantoaxial dislocation who had been treated from January 2021 to October 2022 at Department of Spine Surgery, General Hospital of Southern Theatre Command of PLA with our self-designed posterior reduction forceps. There were 2 males and 3 females, aged 53, 62, 45, 32 and 48 years, respectively. Diagnosis: 1 case of free odontoid process combined with atlantoaxial dislocation, 2 cases of atlantoaxial dislocation, and 2 cases of old odontoid process fracture combined with atlantoaxial dislocation. Respectively, their preoperative Japanese Orthopaedic Association (JOA) scores were 9, 11, 12, 13 and 10 points and their atlanto-dental intervals (ADI) 9.8, 7.4, 6.6, 6.4 and 8.5 mm. Postoperatively, atlantoaxial reduction and spinal cord compression were evaluated by X-ray, CT, and MRI examinations, and internal fixation, atlanto-axial sequence, and bone graft fusion by X-ray and CT examinations. One week after surgery, the JOA scores were used to evaluate the patients' neurological function and the ADI was measured to evaluate the atlantoaxial reduction.Results:The surgery was successfully performed in the 5 patients, with no intraoperative complications like neurovascular injuries to the spinal cord. The postoperative atlantoaxial reduction was satisfactory, the position of internal fixation was good, the compression to the spinal cord was relieved, and the clinical symptoms were significantly improved. At 1 week after surgery, respectively, the JOA score: 13, 14, 14, 15 and 13; the ADI: 2.6, 2.1, 1.8, 1.5 and 2.2 mm; the follow-up time: 3, 6, 12, 9 and 6 months; the bone fusion time: 3, 3, 6, 6 and 3 months. Follow-ups revealed no loosening or fracture of internal fixation, good atlanto-axial sequence, and no recurrence of dislocation.Conclusion:Our self-designed posterior reduction forceps for atlantoaxial dislocation can assist the simple posterior screw-rod system to treat irreducible atlantoaxial dislocation, leading to good preliminary clinical outcomes.