Abstract
Background Anderson and D'Alonzo type II odontoid fractures often require surgical intervention.
Our goal was to understand the pattern of healing in patients who had a posterior
atlantoaxial fusion for a type II odontoid fracture.
Methods We conducted a retrospective study of patients who underwent posterior atlantoaxial
instrumentation and fusion for a type II odontoid fracture at our institution between
1987 and 2011. Patients who had fusion evaluation by computed tomography (CT) scan
≥3 months after surgery were included. Surgical technique included placement of a
posterior bone graft with transarticular screws, C1 lateral mass and C2 pars/pedicle
screw construct, or a combination of screw fixation techniques. Postoperative CT scans
were reviewed to determine the site where fusion occurred.
Results Sixty-four patients underwent posterior atlantoaxial instrumentation and fusion for
type II odontoid fractures, 12 of whom had fusion evaluation by CT scan. A total of
11 of 12 patients had fusion across the fracture site, 2 across the C1–C2 joint, and
11 at the posterior graft site. All 12 patients had at least one site of fusion.
Conclusions There is a high rate of fusion across the fracture site of a type II odontoid fracture
after posterior atlantoaxial fixation. In young patients with acute type II fractures
who are not candidates for anterior screw fixation, posterior atlantoaxial instrumentation
without fusion may be sufficient for fracture healing, thus allowing for the possibility
of implant removal and preservation of C1–C2 motion.
Keywords
type II odontoid fracture - C1–C2 - posterior atlantoaxial fusion - bone graft
