Transarticular screws in the management of C1-C2 instability in children.

C1-C2 instability is a challenging problem in the pediatric population. Small patient size and poor healing potential in the at-risk groups, such as patients with Down syndrome and os odontoideum, make fixation difficult. Instability in patients with Down syndrome is a common problem, and traditional methods of fixation have a high complication rate and are a challenge given the frequent anatomic abnormalities such as an incomplete or hypoplastic arch, os odontoideum, and incomplete passive reduction. The purpose of this study was to review our experience of transarticular screw use in pediatric patients and to define the potential applications of this technique in pediatric C1-C2 instability. Twelve patients, with C1-C2 instability managed with transarticular screws at the authors' institution, were reviewed. The youngest patient treated was 5 years old with a mean age for the group of 11.5 years. The group consisted of 3 patients with Down syndrome and 9 patients with os odontoideum. Three of the patients with os odontoideum failed previous posterior wiring. Two patients presented with an acute spinal cord injury in the setting of chronic instability. Preoperative computed tomography or magnetic resonance imaging was used in all patients to define the vascular and bony anatomy. No further surgery has been required at a mean follow-up of 5.1 years in all patients. Although vertebral size and congenital anomalies may make screw positioning challenging, the technique allows fixation in the absence of a complete posterior arch of C1 and eliminates the need for instrumentation in the canal. This technique also provides a high fusion rate in a complicated patient population.