Long-term impact of atlantoaxial arthrodesis on the pediatric cervical spine

Background: This study was conducted to elucidate radiographically the long-term impact of atlantoaxial arthrodesis on the pediatric cervical spine. Methods: The records of eight children who underwent atlantoaxial arthrodesis for the treatment of upper cervical spinal disorders and were followed up to their adulthood were retrospectively reviewed. Changes in the curvature of the whole cervical spine, and anteroposterior diameters of the spinal canal at C1 and C2 levels were investigated on lateral radiographs before surgery, at 6 months after surgery, and at the final follow-up. Results: The cervical curvature was lordosis or straight before surgery in all children and became sigmoid in six children at 6 months after surgery. At the final follow-up, three of the six children with postoperative sigmoid curvatures regained some degree of lordosis and became straight. The anteroposterior diameters of the spinal canal at C1 and C2 levels did not increase during the follow-up period. Conclusions: Development of postoperative malalignment of the lower cervical spine and impaired growth of the spinal canal at C1 and C2 levels are common after atlantoaxial arthrodesis in children. Postoperative malalignment diminishes during the follow-up period possibly due to remodeling of the pediatric cervical spine, although remodeling of the spinal canal diameter cannot be expected, suggesting the importance of anatomical reduction before or at the time of surgery.