Attending Texas Children's Hospital Houston, Texas, United States
Introduction: Surgical fixation for occipitocervical instability can be challenging due to limitations in occipital instrumentation. Traditional plating systems require sufficient midline occipital bone for hardware placement. Instrumentation is limited when suboccipital craniectomy has been performed and in pediatric patients with thin skull osteology. Rod placement with an acute bend can also be challenging. Lower profile techniques have been described that include transarticular atlantooccipital and occipital condyle screws. Cadaveric studies have demonstrated the feasibility and biomechanical equivalence to traditional plating systems for these techniques, however clinical applications have been limited to case reports and a single case series. We present the largest case series of pediatric patients undergoing transarticular atlantooccipital or occipital condyle screw fixation for occipital cervical instability.
Methods: Three patients underwent transarticular atlantooccipital screw fixation and three patients underwent occipital condylar screw fixation. Clinical presentation, complications, fusion rates, and outcomes were analyzed.
Results: Occipitocervical instability was secondary to congenital skeletal dysplasia in all patients. Presenting symptoms included dysphagia, gait instability, postural headaches, and neck pain. Four patients had Chiari malformation and underwent suboccipital craniectomy and C1 laminectomy. Neuronavigation was used. Transarticular atlantooccipital screws were placed with an entry point at the center of the C1 lateral mass, angled steeply to cross the occiput-C1 joint. Occipital condyle screws were placed with an entry point 4-5 mm lateral to the medial condylar edge. Cervical fixation was performed using C1-2 transarticular, C2 pars, subaxial lateral mass, or pedicle screw technique. There were no intra- or postoperative complications, all hardware was placed as intended, and all patients demonstrated evidence of fusion on CT at 3 months after surgery. At one year follow up, no patient had hardware failure or return of preoperative symptoms.
Conclusion : Transarticular atlantooccipital and condylar screws are safe alternatives to occipital plate fixation and allow rigid fixation for successful arthrodesis.
