Posterior pedicle screw fixation for complex atlantoaxial fractures with atlanto-dental interval of ≥5 mm or C2-C3 angulation of ≥11°

OBJECTIVE Previous studies have demonstrated that the posterior pedicle screw fixation is an effective and safe method to treat atlantoaxial fractures. However, no report focuses on only the complex atlantoaxial fractures with atlanto-dental interval (ADI) of ≥ 5 mm or C2-C3 angulation of ≥ 11°. METHODS This study was to retrospectively evaluate the outcome of 15 patients (six females and nine males; age, 27-55 years) who underwent posterior pedicle screw fixation for the above complex atlantoaxial fractures between July 2006 and March 2011. Fracture combinations included three Jefferson-type II odontoid, four anterior ring-type II odontoid, two posterior ring-type II odontoid, one lateral mass-type II odontoid, one Jefferson-hangman's fracture, three anterior ring-hangman's fracture, and one lateral mass-hangman's fracture. Fracture healing and bone fusion were determined on X-ray scan. Upper limbs, lower limbs, and sphincter functions were assessed using the Japanese Orthopaedic Association (JOA) score. The Frankel grading system was used to determine the neurological situation. RESULTS The mean operative time, blood loss, and hospital stays were 108.9 ± 25.8 min, 508.0 ± 209.6 ml, and 13.3 ± 2.0 days. Fracture healing and graft fusion were obtained in all patients within 9 months. The ADI or C2-C3 angulation was reduced to ≤ 5 mm or ≤ 11°. The JOA score was significantly improved from 7.27 ± 1.10 preoperatively to 15.7 ± 2.1 postoperatively (P < 0.001), with 88.1 ± 18.3% recovery rate and 93.3% excellent and good rate. The neurological situation was improved in all patients by at least 1 grade in the Frankel scale. After a mean of 36.5 months of follow-up (range, 18 to 58 months), no operative complications (spinal cord injury, vertebral artery injury, or cerebrospinal fluid leakage) were observed. CONCLUSION Posterior pedicle screw fixation is a reliable, effective, and minimally invasive procedure for patients suffering from complex atlantoaxial fractures.