Comparison of the Accuracy of C1 Pedicle Screw Fixation Using Fluoroscopy and Free-Hand Techniques in Patients With Posterior Arch Thickness of Less Than 4 mm.

Abstract

C1 pedicle screw insertion is not easy, and more fluoroscopy can be required for safe insertion. Fluoroscopy is time consuming and increases patient radiation exposure. There have been no studies comparing the accuracy of C1 pedicle screw insertion using the fluoroscopy and free-hand techniques. To describe a free-hand C1 pedicle screw insertion method in patients with the posterior arch thickness of less than 4 mm in the thinnest part of the groove, and to compare the clinical and radiological outcomes of C1 pedicle screw insertion using fluoroscopy vs using the free-hand technique. A total of 25 patients who had atlantoaxial instability with a C1 posterior arch<4 mm and were treated with C1 pedicle screw insertion were included. In 10 patients, fluoroscopy was used for C1 pedicle screw insertion, and 15 patients underwent the free-hand technique. We compared the radiologic and clinical outcomes between the 2 groups. In patients who underwent the free-hand technique, 96.5% of screws were rated as safe (grade A or B), and 80.0% of screws in the fluoroscopy group were rated as safe. Postoperative occipital neuralgia occurred in one patient in the fluoroscopy group and did not occur in the free-hand technique group. There was no significant difference in the improvement of Nurick grade between the 2 groups. C1 pedicle screw insertion using the free-hand technique is feasible and safe in patients with a C1 posterior arch<4 mm.