Guided-growth implants in the treatment of early onset scoliosis. A pilot study

The aim of treating children with early onset scoliosis is to guide the growth of the spine until the patients reach skeletal maturity. Regardless of its aetiology, progressive early-onset scoliosis requires multiple-stage surgery, usually at 6 to 12 months' intervals. However, precise coordination of the timing of each consecutive surgical procedure with the child's growth pattern is difficult, and the risk of complications that require additional surgery should be taken into account. The aim of this study is to present a new surgical method of treating early onset scoliosis which consists in a single-stage insertion of special implants that enable three-plane correction of spinal deformities, allows the spine to continue growing, does not require multi-stage surgical distractions, and ends after the growth period with a conventional spinal fusion. The results of this pilot study were obtained in a homogeneous group of patients treated identically by insertion of original implants guiding spinal growth.

The study involved 15 females and 2 males aged between 5 and 13 years (mean age: 9.8 years). All children in the study group had single-curve thoracic scoliosis. The duration of follow-up was between 6 and 40 months (mean duration: 18 months). The efficacy of the guided-growth implant treatment was assessed based on standard radiographs by evaluating the angle of the curvature, T1-S1 length, and apical vertebral rotation (AVR) 1. preoperatively, 2. postoperatively, and 3. in long-term follow-up.

After surgery the scoliosis improved significantly in the range of 51% to 80% (mean improvement: 65%). The degree of the correction depended directly on the initial angle of curvature, which ranged from 56 to 95° (mean angle of curvature: 67°). During the entire follow-up period, twelve patients did not show any loss of correction, or the loss was within the bounds of measurement error. Because of a growth spurt, two female patients had to have the rods replaced with longer ones, since there was a risk that they might slide out of the farthest lower screws. In three patients further spontaneous improvement occurred during the follow-up period. Apical vertebral derotation was achieved during the surgery in all patients, and it was maintained throughout the follow-up period. All patients showed an increase in spinal length in the range of 7 to 40 mm (mean increase: 1mm/month).

1. The surgical method described by us provides for very good correction in the first stage of treatment. 2. The maintenance of the correction does not require the use of corrective braces or any indirect multi-stage surgical procedures. 3. The probability of complications during the insertion of the implants is not higher than that seen with conventional multi-stage treatment.