Dual growing rod technique for the treatment of progressive early-onset scoliosis - A multicenter study

Study Design. A retrospective case review of children treated with dual growing rod technique at our institutions. Patients included had no previous surgery and a minimum of 2 years follow-up from initial surgery. Objectives. To determine the safety and effectiveness of the previously described dual growing rod technique in achieving and maintaining scoliosis correction while allowing spinal growth. Summary of Background Data. Historically, the growing rod techniques have used a single rod and the reported results have been variable. There has been no published study exclusively on the results of dual growing rod technique for early-onset scoliosis. Methods. From 1993 to 2001, 23 patients underwent dual growing rod procedures using pediatric Isola instrumentation and tandem connectors. Diagnoses included infantile and juvenile idiopathic scoliosis, congenital, neuromuscular, and other etiologies. All had curve progression over 10 degrees following unsuccessful bracing or casting. Of 189 total procedures within the treatment period, 151 were lengthenings with an average of 6.6 lengthenings per patient. Analysis included age at initial surgery and final fusion (if applicable), number and frequency of lengthenings, and complications. Radiographic evaluation included measured changes in scoliosis Cobb angle, kyphosis, lordosis, frontal and sagittal balance, length of T1-S1 and instrumentation over the treatment period, and space available for lung ratio. Results. The mean scoliosis improved from 82 degrees (range, 50 degrees-130 degrees) to 38 degrees (range, 13 degrees-66 degrees) after initial surgery and was 36 degrees (range, 4 degrees-53 degrees) at the last follow-up or post-final-fusion. T1-S1 length increased from 23.01 (range, 13.80-31.20) to 28.00 cm (range, 19.50-35.50) after initial surgery and to 32.65 cm (range, 25.60-41.00) at last follow-up or post-final fusion with an average T1-S1 length increase of 1.21 cm per year (range, 0.13-2.59). Seven patients reached final fusion. The space available for lung ratio in patients with thoracic curves improved from 0.87 (range, 0.7-1.1) to 1.0 (range, 0.79-1.23, P = 0.01). During the treatment period, complications occurred in 11 of the 23 patients (48%), and they had a total of 13 complications. Four of these patients (17%) had unplanned procedures. Following final fusion, 2 patients required extensions of their fusions because of curve progression and lumbosacral pain. Conclusion. The dual growing rod technique is safe and effective. It maintains correction obtained at initial surgery while allowing spinal growth to continue. It provides adequate stability, increases the duration of treatment period, and has an acceptable rate of complication compared with previous reports using the single rod technique.