Fluoroscopy-Assisted C1-C2 Posterior Fixation for Atlantoaxial Instability: A Single-Center Case Series of 78 Patients.

Background and Objectives : Posterior C1-C2 fixation, with trans-articular screws (TAS) or screw-rod-construct (SRC), is the main surgical technique for atlantoaxial instability, and can be performed with a fluoroscopy-assisted free-handed technique or 3D navigation. This study aimed to evaluate complications, radiological and functional outcome in patients treated with a fluoroscopy-assisted technique. Materials and Methods : A single-center consecutive cohort study was conducted of all adult patients who underwent posterior C1-C2 fixation, using TAS or CRS, between 2005-2019. Results : Seventy-eight patients were included, with a median follow-up time of 6.8 years. Trauma was the most common injury mechanism (64%), and cervicalgia the predominant preoperative symptom (88%). TAS was used in 33%, and SRC in 67% of cases. Surgery was associated with a significant reduction in cervicalgia (from 88% to 26%, p < 0.001). The most common complications were vertebral artery injury ( n = 2, 2.6%), and screw malposition ( n = 5, 6.7%, of which 2 were TAS and 3 were SRC). No patients deteriorated in their functional status following surgery. Conclusions : Fluoroscopy-assisted C1-C2 fixation with TAS or SRC is a safe and effective treatment for atlantoaxial instability, with a low complication rate, few surgical revisions, and pain relief in the majority of the cases.