C1-2 segmental fixation without anterior screw for the motion-preservative treatment of type II dens injuries

Abstract

Objective To observe the preliminary clinical results of temporary atlantoaxial segmental fixation for motion preservation of type II dens fractures not amenable to anterior cancellous screw fixation. Methods Between 2012 and 2013, thirteen patients with type II dens fractures not amenable to anterior screw fixation were enrolled and treated using temporary C1-2 pedicle screw fixation without fusion, including 10 males and 3 females, aging 18-62 years old (mean, 40 years). The internal fixations were removed after the consolidation of the fractures was radiologically confirmed. Functional CT scan was carried out to evaluate residual atlantoaxial rotation and axial neck rotation at least one month after the implant removal. Results All of 52 pedicle screws were successfully placed and satisfactory fracture reduction was achieved and maintained by internal fixation in all of the 13 patients. No major complication was noted. The average follow-up time was 14.2 months (7 to 20 months). The fusion time after the surgery was 6 to 15 months, with an average of 9.0±2.8 months. At 9 months after initial surgery, the consolidation of the fractures was confirmed with no failure of fixation, and then the internal fixations were removed. The neck pain was released significantly, from preoperative VAS of 6 to 9 points (average, 7.5± 1.0) to postoperative 1 to 3 points with an average of 2.3±0.6. The mean axial neck rotation was 59.7° to the left and 56.8° to the right. The mean atlantoaxial rotation was 17.0° to the left and 17.2° to the right. Total axial neck rotation was a mean of 116.5° and total atlantoaxial rotation was 34.2° on average. Atlantoaxial rotation took up about 27.3% of total axial neck rotation. In comparison to age and gender matched normal individuals, total axial neck rotation was reduced to about 78.2%. Conclusion As an alternative to fusion, posterior reduction and temporary segmental fixation could be a feasible technique for the motionpreservative treatment of type II dens fractures not amenable to anterior screw. Key words: Odontoid process; Fractures, bone; Fracture fixation, internal; Treatment outcome