The rotational angle differences of 34 patients who have undergone Ahci anterior spinal spinal instrumentation and Aha posterior spinal instrumentation were evaluated by CT. Twentyfour of them were idiopathic, 5 of them congenital and the other 5 were paralythic scoliosis. In idiopathic scoliosis; average preoperative Cobb angle for thoracic curves were 52.4° corrected to 10 for an average correction of 79.4 % while for lumbar curves the preoperative Cobb angle was 36.3° corrected to 2.2° for an average correction of 93 %. In paralythic scoliosis; the average preoperative Cobb angle was 83° corrected to 24° for an average correction of 71 % and in congenital scoliosis the Cobb anlge changed from an average of 57.8° to 21° post-operatively for an average correction of 63.7 %.

The average RA (AN1) preoperatively was 19° which improved to 8.7° postoperatively for an average correction of 44 % in idiopathic scoliosis. RA (AN2) improved from 18.9° preoperatively to 10.8° postoperatively (29 %) RA(SAG) improved from 9° preoperatively to 9.15° postoperatively (34.4 %). In congenital scoliosis the average RA(ANl) correction was 4% with an average RA(AN2) correction of 17.6 % and an average RA(SAG) correction of 0.5 %. In paralythic scoliosis, the average correction of RA (AN1) was 33.4 %, the average correction of RA (AN2) was 19.2 % and the average correction of RA(SAG) was 32.6 %.

The change in rotation and in the sagittal and frontal planes of the patients who have undergone Aha ASI and PSI are evaluted both on conventional radiographs and CT.

Keywords: Scoliosis, Rotation, Aha Spinal Instrumentation.