Background & Aims: Idiopathic scoliosis is the most common type of lateral curvature of the spine.�2-3% of children under 16 years old have idiopathic scoliosis greater than 10 degrees, but less than 10% of them require treatment. One treatment method is surgical correction and fusion and different types of instrumentation have been used. The purpose of this study was to evaluate the results of segmental fixation of the spine with Cotrel - Dubousset (CD) instrumentation that we have used in adolescent idiopathic scoliosis patients since 1999.

Materials & Methods:�Thirty patients (22 girls and 8 boys) with the average age of 10-18 years, had gone under one or two stages of the operation from 1999 to 2004. The amount of curves in sagital and coronal plans were measured on standing radiographs with cobb method. Control radiographs were taken immediately after the operation, then 3 month ,6 month later, and  then yearly until 4 years.

Results:�The patients were followed up for 21 months. Average correction was 44.8% in coronal and 10.6 degrees in sagital plans. Apical vertebral rotation didn’t correct significantly, and average rate of it was 0.46 degree. The average correction of apical vertebral translation was 3 cm (1.5-4 cm). Standing and sitting height was increased to 5 cm averagely.

Conclusion: CD instrumentation is a suitable method for correction of spinal deformities in both coronal and sagital plans, specially to preserve thoracic kyphosis and lumbar lordosis, and there is no requirement for post operative external immobilization.