Combined Halo Gravity Traction and Dual Growing Rod Technique for the Treatment of Early Onset Dystrophic Scoliosis in Neurofibromatosis Type 1

OBJECTIVE: To determine the safety and effectiveness of the combined halo gravity traction and dual growing rod technique in achieving and maintaining scoliosis correction while allowing spinal growth. METHODS: From January 2014 to July 2017, 11 patients with dystrophic neurofibromatosis type 1 (NF1)-associated scoliosis, including 7 men and 4 women, underwent combined halo gravity traction and dual growing rod technique procedures. Diagnoses were all dystrophic NF1-associated scoliosis. Patients with a Cobb angle of major curve >60 degrees and flexibility of spine <30% were included in our research. Analysis included age at the time of treatment, levels of instrumentation, number and frequency of lengthening, lengthening distance, and complications. The changes in Cobb angle of scoliosis and T1-S1 length of spine over the treatment period were measured by radiographic evaluation. RESULTS: The average age of treated patients was 7.2 years (range, 5-9 years). Growing rods were lengthened every 6 months through exposure. The mean number of times of lengthening was 3.9 (range, 3-5). The distance of each extension was 1.6 cm (range, 1.0-2.0 cm). The Cobb angle was corrected 41.7% on average after traction, 48.4% after initial surgery, and 53.3% at the last follow-up. T1-S1 length increased 3.4 cm (range, 1.2-5.1 cm) on average over a mean treatment period of 2.2 years, with an average of 1.5 cm/y (range, 0.5-2.3 cm/y). During the treatment period, complication of hook dislodgement occurred in 1 of 11 patients (9.1%). CONCLUSIONS: The combined halo gravity traction and dual growing rod technique can safely and effectively correct NF1-associated scoliosis. This is an ongoing study that requires long-term follow-up.