[Long-term follow-up of C(1)-C(2) pedicle screw fixation for pediatric atlantoaxial dislocation]

Objective: To investigate the clinical curative effect of C(1)-C(2) pedicle screw fixation for pediatric atlantoaxial dislocation after a long-term follow-up. Methods: From March 2005 to April 2011, a total of 12 male and 9 female patients were included, with age from 3 to 9 years old (mean, 6.1 years old). Among them, 14 cases (67%) had typeⅠinstability atlantoaxial dislocation, 7 cases (33%) had type Ⅱ reducible atlantoaxial dislocation. All 21 pediatric patients with atlantoaxial dislocation underwent posterior pedicle screw fixations. Frankel Grade was used to evaluate function before and after treatment. Furthermore, the information of C(1)-C(2) bony fusion, cervical spine alignment, angle of sagittal curvature, and instability of the subaxial spine were collected from all patients preoperatively, immediately postoperatively and during follow-up period. Results: All 21 patients had regular follow-up with an average duration of 96.4 months (range, 65 to 127 months). All children had good bony fusion within 6 months after treatment. There were 9 patients with lordotic alignment and 12 patients with straight alignment before surgery. After surgery, there were 12 patients with lordotic alignment and 9 patients with straight alignment. At the time of the last follow-up, 17 patients had lordotic alignment and 4 patients had straight alignment. No difference was found between pre- and post-operation (P=0.354). The same result was found between post-operation and last follow-up (P=0.095). Neither kyphotic nor swan-neck deformity was found in any of the 21 patients. The mean angle of sagittal curvature decreased from 31.7°±4.3°preoperatively to 15.5°±2.5°postoperatively (P<0.001). The mean angle of sagittal curvature increased from 15.5°±2.5°postoperatively to 19.1°±2.7°at the final follow-up (P=0.343). No spinal deformities or subaxial instabilities were found. Of the four patients with preoperative neurological defects, Frankel Grade was significantly improved at 3 months follow-up compared with pretreatment values. None of the patients experienced worsening neurological symptoms or injury to the vertebral artery. Conclusion: The results demonstrate that C(1)-C(2) pedicle screw fixation could achieve satisfactory clinical effects for the management of pediatric atlantoaxial dislocation with long-term follow-up.