Reducible Nonunited Type II Odontoid Fracture with Atlantoaxial Instability: Outcomes of Two Different Fixation Techniques

Abstract

Displaced nonunited type II odontoid fracture can result in atlantoaxial instability, causing delayed cervical myelopathy. Both Magerl's C1-C2 transarticular screw fixation technique and Harms-Goel C1-C2 screw-rod segmental fixation technique are effective techniques to provide stability. This study aimed to demonstrate the results of two surgical fixation techniques for the treatment of reducible nonunited type II odontoid fracture with atlantoaxial instability. Medical records of patients with reducible nonunited type II odontoid fracture hospitalized for spinal fusion between April 2007 and April 2018 were reviewed. For each patient, specific surgical fixation, either Magerl's C1-C2 transarticular screw fixation technique augmented with supplemental wiring or Harms-Goel C1-C2 screw-rod fixation technique, was performed according to our management protocol. We reported the fusion rate, fusion period, and complications for each technique. Of 21 patients, 10 patients were treated with Magerl's C1-C2 transarticular screw fixation technique augmented with supplemental wiring, and 11 were treated with Harms-Goel C1-C2 screw-rod fixation technique. The bony fusion rate was 100% in both groups. The mean time to fusion was 69.7 (95%CI 53.1, 86.3) days in Magerl's C1-C2 transarticular screw fixation technique and 75.2 (95%CI 51.8, 98.6) days in Harms-Goel C1-C2 screw-rod fixation technique. No severe complications were observed in either group. Displaced reducible, nonunited type II odontoid fracture with cervical myelopathy should be treated by surgery. Both fixation techniques promote bony fusion and provide substantial construct stability.

Keywords: atlantoaxial instability; nonunited odontoid fracture; posterior atlantoaxial fusion.

Figure 1

Radiographic images of nonunited type II odontoid fracture with atlantoaxial instability. Atlantoaxial instability with cervical myelopathy caused by nonunited type II odontoid fracture (Red arrows): (A) lateral plain radiograph; (B) coronal CT image; (C) sagittal MR image.

Figure 2

Patient management protocol at Chiang Mai University Hospital.

Figure 3

Radiographic images of patients with reducible nonunited type II odontoid fracture with myelopathy treated with (A) Magerl’s C1-C2 transarticular screw fixation technique augmented with supplemental wiring and (B) Harms-Goel C1-C2 screw-rod segmental fixation technique. Coronal CT scan imaging (C) shows C1-C2 complex screw construction with solid fusion mass in Harms-Goel C1-C2 screw-rod segmental fixation technique at 3-month follow-up.

Figure 4

Kaplan-Meier curves for fusion probability in both study groups. The blue line depicted the fusion probability of patients in Magerl’s C1-C2 transarticular screw fixation technique group. The red line depicted the fusion probability of patients in the Harms-Goel C1-C2 screw-rod segmental fixation technique group.