Objective To analyze the influence of segmental pedicle screws versus hybrid instrumentation on the correction results in adolescent idiopathic scoliosis patients undergoing posterior selective thoracic fusion. Methods By reviewing the medical records and roentgenograms of adolescent idiopathic scoliosis patients who underwent selective thoracic fusion from February 2000 to January 2007 in our hospital

the patients were divided into 2 groups according to different instrumentation fashions: Group A was hook-screw-rod （hybrid） internal fixation type

Group B was screw-rod （all pedicle screws） internal fixation type

and the screws were used in every segment on the concave side of the thoracic curve. The parameters of the scoliosis were measured and the correction results were analyzed. Results Totally

48 patients （7 males

41 females） were included

with an average age of 14.4 years old and a mean follow-up time of 12.3 months. Thirty and 18 patients were assigned to group A and group B

respectively. The mean preoperative coronal Cobb angles of the thoracic curve were 48.8° and 47.4°

respectively. After surgery

they were corrected to 13.7° and 6.8°

respectively. At final follow-up

they were 17.0° and 9.5°

with an average correction rate of 64.6% and 79.0%

respectively

and the correction rate of group B was significantly higher than that of group A （P=0.003）. The mean preoperative coronal Cobb angles of the lumbar curve were 32.6° and 35.2°

respectively. After surgery

they were corrected to 8.6° and 8.3°

respectively. At final follow-up

they were 10.3° and 11.1°

with an average correction rate of 66.8% and 69.9%

respectively

and the correction rate of group B was significantly higher than that of group A （P=0.003）. The correction loss of the thoracic curve and lumbar curve in the 2 groups were 3.1° and 1.8°

2.4° and 2.4°

respectively. No significant difference was noted （both P>0.05）. The decompensation rate at final follow-up in these 2 groups were 4% （1/25） and 7.1% （1/14） respectively

with no significant difference （P>0.05）.Conclusions Both all pedicle screws and hybrid instrumentation can offer good correction results of the thoracic curve and lumbar curve in posterior selective thoracic fusion in patients with adolescent idiopathic scoliosis. While with all pedicle screws

the correction results of the thoracic curve and lumbar curve are both better than those with hybrid instrumentation without increased decompensation rate.