Aim of the Study: The aim of this work is to radiologically evaluate the postoperative outcomes of spinal instrumentation performed as a treatment for Adolescent Idiopathic Scoliosis (AIS) on 5-year follow up basis, and to correlate with different clinical scenarios. Materials and Methods: One hundred (100) AIS consecutive patients treated with spinal instrumentation were included in this study. The study period was from 2012 to 2017. All patients had radiological evaluations including total spine x-rays, low dose CT scan using Orthopedic Metal Artifact Reduction (OMAR) software and MRI, after obtaining the informed consents and approval of the institution ethical board. Radiological evaluation included Cobb angle measurement assessed pre, postoperatively and at regular intervals within the 5-year period. Results: Of the 100 patients included, 24 were females and 76 were males. The average age at operation was 16.5 years. Sixty seven (67%) patients showed good correction and maintenance of the spinal curves where the mean Cobb angle was 68°?preoperatively and 21°postoperatively, representing a correction rate of 74%. Thirty three (33%) patients showed complications including postoperative infection (13), surgical revision (4), pseudarthrosis (3), neurological deficits (5), screw loosening (7) and complete hardware failure (1);in whom the preoperative mean Cobb angle was 56°compared to the patients with no complications (p = 0.288). In males, there were postoperative complications in 27 out of 76 and in females 5 out of 24, (p = 0.027). The average duration of follow-up was 3.7 years for all cases. Conclusion: Five-year follow up of patients with AIS treated with spinal instrumentation demonstrates good improvement and maintenance of the corrected spinal curves in two thirds of patients, one third showed variable minor and major complications. Low dose CT scan with OMAR provided an effective modality for evaluation.