Anatomical suitability of C1-2 transarticular screw placement in pediatricpatient

Object. Craniovertebral instability is a challenging problem in pediatric s pinal surgery. Recently, C1-2 transarticular screw fixation has been used t o assist in craniovertebral joint stabilization in pediatric patients. Curr ently there are no available data that define the anatomical suitability of this technique in the pediatric population. The authors report their exper ience in treating 31 pediatric patients with craniovertebral instability by using C1-2 transarticular screws. Methods. From March 1992 to October 1998, 31 patients who were 16 years of age or younger with atlantooccipital or atlantoaxial instability, or both, were evaluated at our institution. There were 21 boys and 10 girls. Their a ges ranged from 4 to 16 years (mean age 10.2 years). The most common causes of instability were os odontoideum (12 patients) and ligamentous laxity (e ight patients). Six patients had undergone a total of nine previous attempt s at posterior fusion while at outside institutions. All patients underwent extensive preoperative radiological evaluation inclu ding fine-slice (1-mm) computerized tomography scanning with multiplanar re construction to evaluate the anatomy of the C1-2 joint space. Preoperativel y, of the 62 possible C1-2 joint spaces in 31 patients, 55 sides (89%) were considered suitable for transarticular screw placement. In three patients the anatomy was considered unsuitable for bilateral screw placement. In thr ee patients the anatomy was considered inadequate on one side. Fifty-five C 1-2 transarticular screws were subsequently placed, and there were no neuro logical or vascular complications. Conclusions. The authors conclude that C1-2 transarticular screw fixation i s technically possible in a large proportion of pediatric patients with cra niovertebral instability.