Aim:Lenke Type 1, the main thoracic curve type, is the most common spinal curve pattern in adolescent idiopathic scoliosis (AIS). The aim of this study was to compare the postoperative changes of both sagittal spinal and spinopelvic parameters in patients with Lenke Type 1 AIS who underwent selective and non-selective fusion surgery. Material and Methods: We conducted a retrospective study among 53 Lenke Type 1 AIS patients who underwent corrective surgery at our centre between 2006 and 2012. Patients were classified as group 1 if they underwent selective surgery and as group 2 if they underwent non-selective surgery. Surgical results of preoperative and postoperative sagittal and spinopelvic measurements, pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis (LL) and thoracic kyphosis (TK) values were analysed using the SURGIMAP Software (Nemaris İnc. USA) (https://www.surgimap.com/) measurement system. Results:In both groups, a comparison of pre- and postoperative sagittal spinal parameters did not show a statistically significant difference. In both groups, pre- and postoperative measurements of LL and TK did not show a statistically significant difference. Conclusion:After selective and non-selective surgery, sagittal spinal and spinopelvic parameters are not affected in the middle term. We think that the long-term studies to be done in this regard will increasingly require the necessity of keeping pelvis in mind while evaluating the sagittal plan in the AIS surgery.