To report all complications that occurred during the 2 to 5-year postoperative period, describe reoperations during this time period, and compare patients who did and did not have major, surgery-related complications and/or reoperations during this time period.The Scoli-RISK-1 study enrolled 272 ASD patients undergoing surgery from 15 centers. Inclusion criteria were Cobb angle of > 80°, corrective osteotomy for congenital/revision deformity, and/or 3-column osteotomy. At each follow-up visit, any neurologic or non-neurologic adverse event(AE) was documented & categorized.77 patients had a minimum 5-year follow-up. 35 surgery-related AE's occurred during the 2 to 5-year period in 25(32.5%) patients. 23/35(65.7%) major, surgery-related complications occurred in 17 patients, 22/35(62.9%) requiring reoperations in 16 patients. Rod fracture and/or pseudarthrosis was the most common complication. The most common minor, surgery-related complication was asymptomatic rod fractures with no alignment changes. Four neurological complications were reported, one of which did not require reoperation. One death occurred at 6.1 years postoperative after multiple reoperations for mechanical complications. 14/17(82.4%) patients with major, surgery-related complication had a preceding AE during the initial 2-year postoperative period. 53 non-surgery-related AEs occurred in 21(27.3%) patients with musculoskeletal(37.7%) occurring most often. No differences were observed in ODI or SRS-22r in those with/without major surgery-related complications or those with/without reoperation.During the study period, 25(32.5%) patients experienced 35 surgery-related complications, of which 23(65.7%) were major. Rod fracture with pseudarthrosis was the most common major, surgery-related complication. Neurologic complications were not found to be major drivers of reoperation. Surprisingly, PROs were similar in those with/without a major, surgery-related complication during the study period. This work has been presented as a podium presentation at the 55th Scoliosis Research Society annual meeting, Sep 9-13, 2020.