Laminar screw fixation of the axis in the pediatric population: a series of eight patients.

Abstract

Instability of the atlantoaxial spine is a recognized problem in children. Safe passage of pedicle screws at C2 poses challenges because of the proximity to the vertebral artery, size of the pedicles, and variations in the location of the foramen transversarium. The C2 translaminar technique is a useful option and its stability is comparable to that offered by C2 pedicle screws. In this follow-up from our previously published study, we wanted to verify the safety and suitability of the C2 laminar screw in the treatment of cervical instability in the pediatric population. We present a case series of eight pediatric patients who underwent laminar screw fixation of the axis as part of their operative procedure. There were five girls and three boys, with a mean age of 7 years (range 2-17 years) who underwent this procedure. Surgical indications included atlantoaxial instability, atlanto-occipital disassociation, multilevel cervical instability, and high cervical stenosis. Seven patients had underlying dysplastic syndromes. We studied the technical feasibility of passing laminar screws at C2 in eight consecutive patients, paying attention to screw length and diameter, vascular or neurologic complications, and stability of fixation. This retrospective study was funded by our institution and there was no potential conflict of interest. All patients were placed prone. The posterior aspect of the cervical spine and craniocervical junction were exposed subperiosteally. We report our modification of the Wright technique, which allowed us to safely pass 3.5-mm screws into both laminae of the second cervical vertebra. A total of 15 laminar screws were passed at C2. The follow-up period ranged from 1 to 24 months (mean 8 months). There were no vascular or neurologic complications, no infection, and no instances of hardware failure either by lamina fracture or screw pullout. All patients maintained stable constructs on imaging studies at the last follow-up evaluation. Children as young as 2 years can undergo safe and rigid fixation of the axis. The technique is especially valuable in patients with dysplastic bone and distorted anatomy where more traditional methods of C2 fixation cannot be safely used. To our knowledge, this is the largest reported series of C2 laminar screw fixation in a pediatric population.