Comparison of single and dual growing rod techniques followed through definitive surgery - A preliminary study

Study Design. Retrospective analysis of patients treated with single and dual growing rods who had completed their course of treatment, had definitive fusion, and had a minimum of 2 years follow-up. Objectives. To determine which technique was the most effective in the management of severe spinal deformity in young children: control of the spinal deformity, spinal growth, and the incidence of complications. Summary of Background Data. Growing rod techniques provide proximal and distal segmental "claw" foundations, but their overall results through definitive fusion have not been clearly determined. Methods. A total of 28 consecutive patients who had growing rod procedures followed through definitive spinal fusions were analyzed. There were three patient groups: Group 1 (N=5), single submuscular rod and short apical fusion; Group 2 (N=16), single growing rod alone; and Group 3 (N=7), dual growing rods. Results. The interval between initial rod insertion and definitive spinal fusion was similar in all three groups. The best overall results occurred in Group 3, whereas the patients in Group 1 had the worse results. Both Groups 2 and 3 provided good initial correction of the spinal deformity and allowed spinal growth. Group 2 had better frontal and sagittal plane balance and the lowest complication rate. Conclusion. The use of growing rods is effective in controlling severe spinal deformities and allowing spinal growth. Dual rods are stronger than single rods and, therefore, provide better initial correction and maintenance of correction. The use of an apical fusion does not appear to be effective over the course of treatment.