USE OF AXIAL AND SUBAXIAL TRANSLAMINAR SCREW FIXATION IN THE MANAGEMENT OF UPPER CERVICAL SPINAL INSTABILITY IN A SERIES OF 7 CHILDREN

OBJECTIVE: The management of upper cervical spinal instability in children continues to represent a technical challenge. Traditionally, a number of wiring techniques followed by halo orthosis have been applied; however, they have been associated with a high rate of nonunion and poor tolerance for the halo. Alternatively, C1-C2 transarticular screws and C2 pars/pedicle screws allow more rigid fixation, but they are technically demanding and associated with vertebral artery injuries. Recently, C2 translaminar screws have been added to the armamentarium of the pediatric spine surgeon as a technically simple and biomechanically efficient method of fixation. However, subaxial translaminar screws have not been described in the pediatric population. We describe our experience with axial and subaxial translaminar screws in 7 pediatric patients. METHODS: Seven pediatric patients with the diagnosis of upper cervical spinal instability required surgical fixation (age, 19 months-14 years; sex, 4 boys and 3 girls; follow-up, 4-21 months; etiology, trauma [3 patients], os odontoideum/os terminale [2 patients), hypoplastic dens [2 patients]). All patients underwent axial and/or subaxial translaminar screw insertion. iliac crest bone graft was used for fusion in 4 patients; bone morphogenic protein and cancellous morselized allograft was used for fusion in 3 patients. A rigid cervical collar was applied for 12 weeks postoperatively in all cases. No intraoperative image guidance was used for insertion of the translaminar screws. RESULTS: All patients had a postoperative computed tomographic scan. Two patients underwent placement of bilateral crossing C2 translaminar screws. Two patients had subaxial translaminar screw placement at C3 and the upper thoracic spine, respectively. Hybrid constructs (a C2 translaminar screw combined with a C2 pars screw) were incorporated in 3 patients. No patients were found to have a breach of the ventral laminar cortex. All patients achieved solid fusion. One patient had a perioperative complication: prolonged dysphagia probably related to C1 lateral mass screw insertion rather than C2 translaminar screw placement. CONCLUSION: To our knowledge, this report represents the only series of pediatric patients treated with axial and subaxial translaminar screws. This series shows that axial and subaxial translaminar screw fixation is a viable option for upper cervical spinal fusion in children. The technique is safe and results in adequate fixation with high fusion rates and minimal complications.