Long-term maintenance of cervical alignment after occipitocervical and atlantoaxial screw fixation in young children

Object. Despite decades of surgical experience, the long-term consequences of occipitocervical (OC) and atlantoaxial (C1-2) fusions in children are unknown. The purpose of this study was to determine the long-term effects of these fusions on growth and alignment of the maturing cervical spine. Methods. A retrospective chart review was conducted for patients 6 years of age or younger (mean 4.7 years, range 1.7-6.8 years) who underwent OC or C1-2 fusion at the Primary Children's Medical Center at the University of Utah within the last 10 years. Immediate postoperative plain radiographs and computed tomography (CT) scans were compared with the most recent plain and dynamic radiographs to assess changes in spinal growth and alignment. Seventeen children met entry criteria for the study. All patients had fusion documented on follow-up radiography or CT scans. At a mean follow up of 28 months, there were no cases of sagittal malalignment (kyphotic or swan-neck deformity), subaxial instability (osteophyte formation or subluxation), or unintended fusion of adjacent levels. The lordotic curvature of the cervical spine increased from a mean of 15° postoperatively to 27° at follow up (p = 0.06). A mean of 34% of the vertical growth of the cervical spine occurred within the fusion segment. When data were analyzed pertaining to a subgroup of five patients who underwent follow-up periods for longer than 48 months (mean 50.2 months, range 48-54 months), similar results were seen. Conclusions. Preliminary follow-up results indicate that, compared with older children, children 6 years of age or younger undergoing OC or C1-2 fusion are not at an increased risk of spinal deformity or subaxial instability. Longer follow-up periods, during which measurements of the spinal canal are taken, will be necessary to determine precisely how children's spines grow and remodel after an upper cervical spine fusion.