Motion-Preserving Navigated Primary Internal Fixation of Unstable C1 Fractures

Study Design: Prospective observational study. Purpose: To assess the safety, efficacy, and benefits of computed tomography (CT)-guided C1 fracture fixation. Overview of literature: The surgical management of unstable C1 injuries by occipitocervical and atlantoaxial (M) fusion compromises motion and function. Monosegmental C1 osteosynthesis negates these drawbacks and provides excellent functional outcomes. Methods: The patients were positioned in a prone position, and cranial traction was applied using Mayfield tongs to restore the CD-C2 height and obtain a reduction in the displaced fracture fragments. An intraoperative, CT-based navigation system was used to enable the optimal placement of C1 screws. A transverse rod was then placed connecting the two screws, and controlled compression was applied across the fixation. The patients were prospectively evaluated in terms of their clinical, functional, and radiological outcomes, with a minimal follow-up of 2 years. Results: A total of 10 screws were placed in five patients, with a mean follow-up of 40.8 months. The mean duration of surgery was 77 +/- 13.96 minutes, and the average blood loss was 84.4 +/- 8.04 ml. The mean combined lateral mass dislocation at presentation was 14.6 +/- 1.34 mm and following surgery, it was 5.2 +/- 1.64 mm, with a correction of 9.4 +/- 2.3 mm (p<0.001). The follow-up CT showed excellent placement of screws and sound healing. There were no complications and instances of AA instability. The clinical range of movement at 2 years in degrees was as follows: rotation to the right (73.6 degrees +/- 9.09 degrees), rotation to the left (71.6 degrees +/- 5.59 degrees), flexion (35.4 degrees +/- 4.5 degrees), extension (43.8 degrees +/- 8.19 degrees), and lateral bending on the right (28.4 degrees +/- 10.45 degrees) and left (24.8 degrees +/- 11.77 degrees). Significant improvement was observed in the functional Neck Disability Index from 78 +/- 4.4 to 1.6 +/- 1.6. All patients returned to their occupation within 3 months. Conclusions: Successful C1 reduction and fixation allows a motion-preserving option in unstable atlas fractures. CT navigation permits accurate and adequate monosegmental fixation with excellent clinical and radiological outcomes, and all patients in this study returned to their preoperative functional status.